GENERAL STATEMENT OF THE CLASS SUBJECT MATTER
This is the generic class for electrical apparatus and corresponding methods for performing calculation operations.
SCOPE OF THE CLASS
(1) Note. This class is limited to electrical and calculating computer apparatus and corresponding methods wherein a calculation operation is performed on information carried by wave propagation (either electromagnetic or compressional waves) provided that input to and output from the apparatus is electrical. Note: where the apparatus performing the calculation operation is electrically responsive but the data is not presented to and output from the apparatus as electrical signals, classification is with the appropriate wave energy subject matter, as per one of the optical classes.
(2) Note. Significantly claimed apparatus external to this class, claimed in combination with apparatus under the class definition, which perform data processing or calculation operations are classified in the class appropriate to the external device unless specifically excluded therefrom.
(3) Note. Nominally claimed apparatus external to this class in combination with apparatus under the class definition is classified in this class unless provided for in the appropriate external class.
THIS CLASS IS STRUCTURED INTO THREE MAIN DIVISIONS:
A. Electrical Hybrid Calculating Computers
B. Electrical Digital Calculating Computers
C. Electrical Analog Calculating Computers

REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:
235, Registers, various subclasses for basic machines and associated indicating mechanisms for ascertaining the number of movements of various devices and machines, plus machines made from these basic machines alone (e.g., cash registers, voting machines)or in combination with various perfecting features, such as printers and recording means, as well as for various data bearing record controlled systems.
307, Electrical Transmission or Interconnection Systems, various subclasses for generic residual electrical
transmission or interconnection systems and miscellaneous circuits.
326, Electronic Digital Logic Circuitry, various subclasses for digital logic devices.
327, Miscellaneous Active Electrical Nonlinear Devices, Circuit, and Systems, various subclasses for miscellaneous active device analog circuits.
340, Communications: Electrical, various subclasses for residual electrical communication systems.
341, Coded Data Generation or Conversion, various subclasses for electrical pulse and digital code converters.
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, various subclasses for the selective control of two or more light generating or light controlling display elements in accordance with a received image signal.
359, Optics: Systems (Including Communication) and Elements, subclasses 107+ for optical computing without diffraction and subclasses 237+ for optical modulators.
360, Dynamic Magnetic Information Storage or Retrieval, appropriate subclasses for record carriers and systems wherein information is stored and retrieved by interaction with a medium and there is relative motion between a medium and a transducer, for example, magnetic disk drive devices and control thereof, per se.
361, Electricity: Electrical Systems and Devices, subclasses 679+ for housing or mounting of electronic device or system which may provide keyboard or computer support.
364, Electrical Computers and Data Processing Systems, subclasses 130+ for data processing control systems, subclasses 400+ for particular application of electrical computers and data processing systems.
365, Static Information Storage and Retrieval, various subclasses for addressable static singular storage elements or plural singular storage elements of the same type.
369, Dynamic Information Storage or Retrieval, various subclasses for record carriers and systems wherein information is stored and retrieved by interaction with a medium and there is relative motion between a medium and a transducer.
370, Multiplex Communications, various subclasses for generic multiplexing and demultiplexing systems.
375, Pulse or Digital Communications, various subclasses for generic pulse or digital communication systems.
377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems, various subclasses for generic circuits for pulse counting.
379, Telephonic Communications, various subclasses for two-way electrical communication of intelligible audio information of arbitrary content over a link including an electrical conductor.
382, Image Analysis, appropriate subclasses for operations performed on image data with the aim of measuring a characteristic of an image, detecting variations, detecting structures, or transforming the image data, and for procedures for analyzing and categorizing patterns present in image data.
395, Information Processing System Organization, subclasses 80+ for robot control, subclasses 101+ for static data presentation processing, and subclasses 500 and 527 for simulation, emulation, or compatability of system components.
701, Data Processing: Vehicles, Navigation, and Relative Location, appropriate subclasses for vehicular or navigational data processing.
702, Data Processing: Measuring, Calibrating, and Testing, appropriate subclasses for measuring or testing data processing.
704, Data Processing: Speech Signal Processing, Linguistics, Language Translation, and Audio Compression/Decompression for speech, language or audio compression/decompression processing.
705, Data Processing: Financial, Business Practice, Management, or Cost/Price Determination, appropriate subclasses for data processing related to business, finances, management, or cost/price determining.
706, Data Processing: Artificial Intelligence, appropriate subclasses for processing of artificial intelligence.
707, Data Processing: Databases and File Management, Data Structures, and Document Processing appropriate subclasses for database structure, database/file management, or document processing.
709, Electrical Computers and Digital Processing Systems: Multiple Computer or Process Coordinating, appropriate subclasses for computers and digital processing related to plural computers or plural process coordinating.
710, Electrical Computers and Digital Processing Systems: Input/Output, appropriate subclasses for input/output processing (e.g., bus processing) in a computer or digital
data processing system.
711, Electrical Computers and Digital Processing Systems: Memory, appropriate subclasses for storage accessing, control, or addressing in a computer or digital processing system.
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing (e.g., Processors), appropriate subclasses for computer or digital processing system architecture or instruction processing.
713, Electrical Computers and Digital Processing Systems: Support, appropriate subclasses for computer or digital processing system support ( e.g., security, power supply, and timing, etc. )
714, Error Detection/Correction and Fault Detection/Recovery, appropriate subclasses for error or fault detection or compensation in a computer or digital processing system.
III
CALCULATION OPERATIONS
Arithmetic or some limited logic operations performed upon or with signals representing numbers or values. These include arithmetic and related logic operations. A related logic operation is one that is associated with arithmetic computations.
DISCRETE ELECTRICAL SIGNAL
Discontinuous signals which can assume only a finite number of states.
NUMERICAL DIGITS
Symbols that represent a specific quantity or amount of units.

ELECTRICAL HYBRID CALCULATING COMPUTER:
This subclass is indented under the class definition. Subject matter wherein a calculation operation is performed either simultaneously or sequentially upon at least one analog and at least one digital signal or wherein either the analog or digital signal is involved in a calculation operation on the other signal.
(1) Note. This subclass does not include the mere
conversion from one signal format to another, which conversion has no part in the above calculation operation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 100+ for electrical digital calculating computers.
subclasses 800+ for electrical analog calculating computers.

Plural complete computers:
This subclass is indented under subclass 1. Subject matter which includes at least one complete analog computer and one complete digital computer.

Particular function performed:
This subclass is indented under subclass 1. Subject matter directed to a particular function performed by hybrid computer or subcombination thereof in making computation.
(1) Note. For classification herein, the function performed must be significantly claimed in making a computation.

Evaluation of trigonometric function:
This subclass is indented under subclass 3. Subject matter wherein the function performed is the processing of signal to either determine a trigonometric relationship or to operate on a signal in accordance with a trigonometric relationship.

SEE OR SEARCH THIS CLASS, SUBCLASS:
440 and 811+ for electrical digital or electrical analog computers which perform the function of evaluation of trigonometric functions.

Correlation, convolution, or transformation:
This subclass is indented under subclass 3. Subject matter wherein the function performed is cross-correlation, autocorrelation, cross-convolution, autoconvolution or transforming a given representation of a data signal to another representation without loss of information by an orthogonal transformation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 400+ 420+, 422+, 813+, and 820+ for electrical digital or analog computers which perform the function of correlation, convolution or transformation.

Integration or differentiation:
This subclass is indented under subclass 3. Subject matter wherein the function performed is integration or differentiation of at least one of a plurality of input signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:
443 and 444, for electrical digital calculating differentiation and integration, respectively computers which perform.
822 and 823+, for electrical analog computers which perform differentiation and integration, respectively.

Multiplication or division:
This subclass is indented under subclass 3. Subject matter wherein the function performed is multiplication or division to produce a product or quotient from at least two input signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 620+ and 650+, for electrical digital computers for performing the function of multiplication or division.
subclasses 835+ and 844, for electrical analog computers for performing the function of multiplication or division.

Function generation:
This subclass is indented under subclass 3. Subject matter wherein the function performed is the generation of at least one signal by mathematical operation or as part of a mathematical operation generates a signal representing a function of at least one variable input parameter.
(1) Note. This subclass includes a waveform synthesizer wherein the waveform is internally generated.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 270+ and 845+, for electrical digital or electrical analog computers which perform the function of function generation.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclasses 100+ for miscellaneous signal converting, shaping, or generating circuits.

Piece-wise linear synthesis:
This subclass is indented under subclass 8. Subject matter wherein the desired function is approximated by a series of segments of straight lines.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 846+ for analog computer piece-wise linear synthesis.

ELECTRICAL DIGITAL CALCULATING COMPUTER:
This subclass is indented under the class definition. Subject matter wherein a calculation operation is performed upon discrete electrical signals representing a value normally described by numerical digits.
(1) Note. The value described includes a value represented by a pulse repetition rate.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 1+ for electrical hybrid calculating computers.
subclasses 800+ for electrical analog calculating computers.

SEE OR SEARCH CLASS:
326, Electronic Digital Logic Circuitry, appropriate subclasses for digital logic devices.

Pulse repetition rate:
This subclass is indented under subclass 100. Subject matter wherein quantities are determinable from the pulse repetition frequency of the discrete electrical signal.

SEE OR SEARCH CLASS:
341, Coded Data Generation or Conversion, subclasses 54+ for digital conversion where a bit is represented by a discrete frequency.

Digital differential analyzer:
This subclass is indented under subclass 101. Subject matter utilized as a digital differential analyzer.

SEE OR SEARCH THIS CLASS, SUBCLASS:
804 for analog differential analyzers.

Multiplication or division:
This subclass is indented under subclass 101. Subject matter wherein the operation performed on an electrical signal is multiplication or division.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclasses 113+ for miscellaneous frequency control.
332, Modulators, subclasses 112+ for pulse frequency modulators.
377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems, appropriate subclasses for pulse dividing and multiplying circuits.

Plural complete computers:
This subclass is indented under subclass 100. Subject matter which includes at least two complete digital computers.

SEE OR SEARCH THIS CLASS, SUBCLASS:
2 for a hybrid computer formed from plural complete computers.

SEE OR SEARCH CLASS:
364, Electrical Computers and Data Processing Systems, subclasses 131+, for plural programmable computers used in a control system.

Combined with diverse art device:
This subclass is indented under subclass 100. Subject matter which includes a diverse art device having a noncalculating function, with common structure utilized in performing the calculating and the noncalculating functions, or an integrated unit into which the computer and diverse art device are embodied.
(1) Note. Search the art area of the diverse device for the details of the diverse device which are claimed.

Checkbook:
This subclass is indented under subclass 105. Subject matter where the diverse device is a checkbook.

SEE OR SEARCH CLASS:
283, Printed Matter, subclass 58 for banking checks, per se.

Writing instrument (e.g., pen):
This subclass is indented under subclass 105. Subject matter where the diverse device is utilized for a hand-held marking purpose.

SEE OR SEARCH CLASS:
401, Coating Implements With Material Supply, appropriate subclasses for pens or pencils, per se.

Tape recorder:
This subclass is indented under subclass 105. Subject matter where the diverse device is a tape recorder.

SEE OR SEARCH CLASS:
360, Dynamic Magnetic Information Storage or Retrieval, appropriate subclasses, for detail of a magnetic tape recorder, per se.

Communication device (e.g., telephone, radio, television):
This subclass is indented under subclass 105. Subject matter where the diverse device transfers information between distant points.

SEE OR SEARCH CLASS:
348, Television, subclass 552 for particular television structure combined with a calculator.
379, Telephonic Communications, subclass 110.01 for particular telephonic substation structure combined with a calculator.
455, Telecommunications, subclasses 344+ for particular receiver or analog modulated signal frequency converter structure combined with a calculator.

Business device (e.g., billing, memorandum):
This subclass is indented under subclass 105. Subject matter where the diverse device is used in the conducting of trade.
(1) Note. Typical of subject matter found here would be a calculator of generic utility combined with a customer billing device.

SEE OR SEARCH CLASS:
705, Data Processing: Financial, Business Practice, Management, or Cost/Price Determination, appropriate subclasses for data processing systems exclusively designed for or utilized in a business environment.

Horological device:
This subclass is indented under subclass 105. Subject matter where the diverse device measures or indicates time.

SEE OR SEARCH CLASS:
368, Horology: Time Measuring Systems or Devices, subclass 10 for a nominal digital calculating computer in combination with a horological device.

Calendar:
This subclass is indented under subclass 111. Subject matter where the horological device provides indication of a day of the week or a date.

SEE OR SEARCH CLASS:
368, Horology: Time Measuring Systems or Devices, subclasses 28+ for a calendar indicator, per se.

Programmable calculator:
This subclass is indented under subclass 100. Subject matter which includes a calculator that is programmable.
(1) Note. Calculator does not include general purpose computers but is restricted to the limited capacity calculator such as desk calculator or a pocket calculator.

SEE OR SEARCH CLASS:
713, Electrical Computers and Digital Processing Systems: Support, subclass 321 for a programmable calculator with power saving feature.

Having specialized input:
This subclass is indented under subclass 100. Subject matter with specialized input in conjunction with calculation portion.
(1) Note. For classification herein, the calculating portion must be a significant component and the input to the calculating portion must be more than nominally recited.

SEE OR SEARCH CLASS:
200, Electricity: Circuit Makers and Breakers, subclass 5 for a multiple switch assembly, per se.
235, Registers, subclasses 145+ for keyboards.
341, Coded Data Generation and Conversion, subclasses 22+ for a keyboard controlled code transmitting device.
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, subclasses 156+ for display peripheral interface input device.
348, Television, subclass 552 for video input devices for computers.
710, Electrical Computers and Digital Processing Systems: Input/Output, appropriate subclasses for input/output and bus data processing.

Having supplemental environment related input:
This subclass is indented under subclass 131. Subject matter where input unique to a particular art area can be provided in addition to normal calculator input.
(1) Note. Typically found here is non-numeric environment related input.

Cooking:
This subclass is indented under subclass 132. Subject matter where the supplemental input relates to the preparation of food for consumption.
(1) Note. Typical of subject matter found here is nonnumeric input designating a particular food to be cooked.

SEE OR SEARCH CLASS:
99, Foods and Beverages: Apparatus, subclasses 324+ for particular cooking apparatus.

Business:
This subclass is indented under subclass 132. Subject matter where the supplemental input relates to the conduct of trade.

SEE OR SEARCH CLASS:
705, Data Processing: Financial, Business Practice, Management, or Cost/Price Determination, appropriate subclasses for data processing systems exclusively designed for or utilized in a business environment.

For security:
This subclass is indented under subclass 131. Subject matter where a specialized input controls accessing of the calculating computer.

Input verification:
This subclass is indented under subclass 131. Subject matter where the specialized input provides a check of intended versus actual input.

Fraction input:
This subclass is indented under subclass 131. Subject matter where the specialized input permits entry of a fraction.

Flexible input:
This subclass is indented under subclass 131. Subject matter in which some portion of the input is made nonrigid to facilitate data entry.

Including specific computing system interconnection:
This subclass is indented under subclass 131. Subject matter for specific structure within the specialized input serving as an interface between the device actually manipulated by the operator and computing circuitry.
(1) Note. Included here would be keyboard input which includes specific structure linking the keyboard, per se, with computing circuitry, for example.

Modular or overlay:
This subclass is indented under subclass 131. Subject matter where plug-in modules or overlays are utilized to effect data input.

Including specific nonkeyboard-type information entry:
This subclass is indented under subclass 131. Subject matter where information ultimately conveyed to the calculating portion is produced by a particular device not having plural individually actuatable keys.

Including specific keyboard-type information entry:
This subclass is indented under subclass 131. Subject matter where information ultimately conveyed to the calculating portion is produced by a particular device having plural individually actuatable keys.

SEE OR SEARCH CLASS:
200, Electricity: Circuit Makers and Breakers, appropriate subclasses for switches, per se.
341, Coded Data Generation or Conversion, subclasses 22+ for a keyboard controlled code transmitting device.
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, subclasses 168+ for display peripheral interface input device including keyboard.

Nonmechanical key actuation:
This subclass is indented under subclass 142. Subject matter where input keys are operated by other than a push and release sequence (e.g., magnetic activation).

SEE OR SEARCH CLASS:
335, Electricity: Magnetically Operated Switches, Magnets, and Electromagnets, appropriate subclasses for magnetic switches, per se.
337, Electricity: Electrothermally or Thermally Actuated Switches, appropriate subclasses for thermal switches per se.

User definable key:
This subclass is indented under subclass 142. Subject matter in which the user defines the function associated with a keyboard key.

SEE OR SEARCH CLASS:
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, subclass 172 for a display peripheral keyboard having a programmable function key.

Plural function key:
This subclass is indented under subclass 142. Subject matter where a keyboard key has plurality of selectable predetermined functions associated with it.

Key sequencing (i.e., sequence defines function):
This subclass is indented under subclass 142. Subject matter where the order in which a plurality of keys is actuated determines the function to be performed.

Having specialized output:
This subclass is indented under subclass 100. Subject matter with specialized output in conjunction with calculating portion.
(1) Note. For classification herein, the calculating portion must be a significant component and the output from the calculating portion must be more than nominally recited.

SEE OR SEARCH CLASS:
340, Communication: Electrical, subclass 815.4 for visual indicators.
345, Computer Graphics Processing, Operator Interface Processing, and Selective Visual Display Systems, appropriate subclasses for selective visual display systems and computer graphics processing.
710, Electrical Computers and Digital Processing Systems: Input/Output, appropriate subclasses for input/output and bus
data processing.

Having supplemental environment related output:
This subclass is indented under subclass 160. Subject matter where output unique to a particular art area can be provided in addition to normal calculator output.
(1) Note. Typically found here is non-numeric environment related output.

Teaching:
This subclass is indented under subclass 161. Subject matter where the supplemental output relates to education.

SEE OR SEARCH CLASS:
434, Education and Demonstration, appropriate subclasses for instructional devices, per se.

Business:
This subclass is indented under subclass 161. Subject matter where the supplemental output relates to the conduct of trade.

SEE OR SEARCH CLASS:
705, Data Processing: Financial, Business Practice, Management, or Cost/Price Determination, appropriate subclasses for data processing systems exclusively designed for or utilized in a business environment.

Output verification:
This subclass is indented under subclass 160. Subject matter in which the output is provided in a form permitting checking thereof (e.g., trace).

Blanking:
This subclass is indented under subclass 160. Subject matter where the specialized output has provision for suppressing a selected portion of the output.

Zero suppression:
This subclass is indented under subclass 165. Subject matter wherein the blanking means has zero suppression capability.

Prompting:
This subclass is indented under subclass 160. Subject matter where the specialized output provides the user with guidance regarding future information entry.

Selective output:
This subclass is indented under subclass 160. Subject matter where the specialized output permits choosing the desired output from a plurality of candidates.

SEE OR SEARCH THIS CLASS, SUBCLASS:
174 for multiple simultaneous outputs.

Sequential output:
This subclass is indented under subclass 160. Subject matter where the specialized output provides successive portions of a desired output one at a time.

Using particular format:
This subclass is indented under subclass 160. Subject matter where the specialized output provides the output in a specified form.
(1) Note. The particular format might be engineering notation or floating point, for example.

Symbol accompanying output:
This subclass is indented under subclass 160. Subject matter in which the specialized output provides a special symbol with the output representation.

Audio:
This subclass is indented under subclass 160. Subject matter where the specialized output is in audible form.

SEE OR SEARCH CLASS:
364, Electrical Computers and Data Processing Systems, subclasses 131+, for plural programmable computers used in a control system.
381, Electrical Audio Signal Processing Systems and Devices, appropriate subclasses for electrical audio signal processing in general.

Printer:
This subclass is indented under subclass 160. Subject matter in which the specialized output provides the output representation in permanent readable form.

SEE OR SEARCH CLASS:
347, Incremental Printing of Symbolic Information, appropriate subclasses for incremental printing (e.g., ink jet printing).
395, Information Processing System Organization, subclasses 101+ for static presentation processing (e.g., for a printer).

Multiple simultaneous outputs:
This subclass is indented under subclass 160. Subject matter where a plurality of output representations are made available by the specialized output at the same time.

SEE OR SEARCH THIS CLASS, SUBCLASS:
168 for selective output.

Integrated circuit:
This subclass is indented under subclass 100. Subject matter wherein the calculating is effected by an integrated circuit or chip, the use or specific structure or arrangement of which significantly affects or directs the handling of information.

SEE OR SEARCH CLASS:
257, Active Solid-State Devices (e.g., Transistors, Solid-State Diodes), appropriate subclasses for integrated circuit structure with active solid-state devices, subclass 446 and 499+ for integrated circuit devices with electrically isolated components, in general, and other appropriate subclasses for specific type devices in integrated circuits.
326, Electronic Digital Logic Circuitry, subclasses 101+ for electronic logic with significant integrated structure.
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclasses 564+ for miscellaneous circuits with integrated structure.

Electro-optical:
This subclass is indented under subclass 100. Subject matter wherein the calculating is effected by electro-optical devices.

SEE OR SEARCH CLASS:
359, Optics: Systems (Including Communication) and Elements subclasses 107+ for optical computing without diffraction
and subclasses 237+ for optical modulators.

Bubble-domain:
This subclass is indented under subclass 100. Subject matter wherein the calculating is effected by bubble-domain devices.

SEE OR SEARCH CLASS:
365, Static Information Storage and Retrieval, subclasses 1+ for magnetic bubble-domain devices used for storage of information.

Particular function performed:
This subclass is indented under subclass 100. Subject matter having a particular function involving a calculation performed by digital computer or subcombination thereof.
(1) Note. For classification herein, the calculating performed in effecting the function must be significantly claimed.

SEE OR SEARCH CLASS:
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing ( e.g., Processors) subclasses 1+ for particular processing architecture which could be utilized in performing the particular function.

Absolute value or magnitude:
This subclass is indented under subclass 200. Subject matter wherein the particular function determines the absolute value or magnitude of a result from an arithmetic operation.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclass 354 for a specific input-to-output function performed by an absolute value.

Median:
This subclass is indented under subclass 200. Subject matter wherein the particular function provides the middle value in a series.

Compression/decompression:
This subclass is indented under subclass 200. Subject matter for representing a number or group of numbers by a smaller number of digits than that possessed originally or the inverse operation.

SEE OR SEARCH CLASS:
341, Coded Data Generation or Conversion, subclass 60 for digital conversion to or from a packed format.
348, Television, subclasses 384+ for a bandwidth reduction system.
382, Image Analysis, subclasses 232+ for data compression in an image processing system.
709, Electrical Computer and Digital Processing Systems: Multiple Process or Process Coordinating subclasses 247+ for data compressing/decompressing in computer data transfer.

Format conversion:
This subclass is indented under subclass 200. Subject matter for changing a number having a representation in one form to a representation in another form.

SEE OR SEARCH CLASS:
341, Coded Data Generation or Conversion, subclasses 50+ for digital-to-digital converters.

Normalization:
This subclass is indented under subclass 204. Subject matter in which the number in final form includes a single nonzero digit to the left of a radix point.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 495+ for floating point systems.

Unit conversion:
This subclass is indented under subclass 200. Subject matter where a number reflecting a first system of measurement is changed to reflect a second system of measurement.
(1) Note. Included here are such conversions as English to metric.

Maximum/minimum determination:
This subclass is indented under subclass 200. Subject matter in which the largest or smallest of a group of numbers is found.

Scaling:
This subclass is indented under subclass 200. Subject matter where a number is modified by a predetermined multiplicative factor.

Shifting:
This subclass is indented under subclass 200. Subject matter where a number is changed by moving each digit therein simultaneously a specified number of positions in a specified direction.
(1) Note. Digits that are shifted beyond the confines of the number may or may not be recirculated into the opposite end of the number. Fixed digits may be inserted there
instead.

SEE OR SEARCH CLASS:
377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and systems, appropriate subclasses for shift registers.
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing (e.g., Processors), subclass 898 for byte word order rearranging.

Determining number of like-valued bits in word:
This subclass is indented under subclass 200. Subject matter where the number of 1's or the number of 0's in a binary word is determined.

Determining number of like-valued leading or trailing bits:
This subclass is indented under subclass 200. Subject matter where the number of consecutive leading or trailing 1's or 0's in a binary word is determined.

Detecting particular sequence of bits:
This subclass is indented under subclass 200. Subject matter for locating a particular string of bits in a larger string of bits.

SEE OR SEARCH CLASS:
375, Pulse or Digital Communications, subclasses 354+ for synchronizers, per se.
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing (e.g., Processors), subclass 898 for byte-word sequence detecting.

Multifunctional:
This subclass is indented under subclass 200. Subject matter wherein the electric digital calculating computer provides for selectively performing at least one logical operation as well as at least one arithmetical operation relative to operands (e.g., a programmable logic circuit with computational means).

SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, subclasses 407+ for nonlinear reactor logic circuits.
326, Electronic Digital Logic Circuitry, subclasses 37+ for programmable logic circuits not performing arithmetic calculations and which are typically solid state.
365, Static Information Storage and Retrieval, appropriate subclasses for programmable logic circuits which include storage and retrieval of information.

Microprocessor:
This subclass is indented under subclass 230. Subject matter wherein the multifunctional operation is performed by a microprocessor.

SEE OR SEARCH THIS CLASS, SUBCLASS:
303 for a particular microprocessor used in a filtering operation.
510 for a particular microprocessor used in floating point.

SEE OR SEARCH CLASS:
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing (e.g., Processors), subclasses 32+ for particular microprocessor architecture.

Array of elements (e.g., AND/OR array, etc.):
This subclass is indented under subclass 230. Subject matter wherein the multifunctional operation is performed by a group of many similar, basic, complex, or integrated elements without separated enclosures, such as AND/OR arrays, etc.

Pipeline:
This subclass is indented under subclass 230. Subject matter wherein the multifunctional operation is performed in a pipeline where the output of one task is input to another until a desired sequence of tasks has been carried out.

SEE OR SEARCH THIS CLASS, SUBCLASS:
406 for Fourier transformation performed in a particular pipeline.
508 for floating point performed in a particular pipeline.
521 for arithmetical pipeline operation in general.
631 for multiple digit binary multiplication performed in a particular pipeline.

Parallel bit input of operand:
This subclass is indented under subclass 230. Subject matter wherein the multifunctional operation is performed in bit level and the bits of operands are input in parallel.

Uses look-up table:
This subclass is indented under subclass 230. Subject matter wherein the operation involves a look-up table to search for a desired item of information.

More than two operands:
This subclass is indented under subclass 230. Subject matter wherein the operations involve three or more operands.

Random number generation:
This subclass is indented under subclass 200. Subject matter
wherein the computer generates a number or sequence of numbers characterized by unpredictability so that no number is any more likely to occur at a given time or place in a sequence than any other.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclass 164 for a miscellaneous circuit producing a rectangular waveform having a random characteristic (e.g., random width).
331, Oscillators, subclass 78 for electrical noise or random wave generation by oscillators (e.g., random pulse generators).

Oscillator controlled:
This subclass is indented under subclass 250. Subject matter wherein the generation is effected by an oscillator or clock.

Linear feedback shift register:
This subclass is indented under subclass 250. Subject matter wherein the generation is performed by a feedback shift register in which a proportional relationship exists between an input and output.

SEE OR SEARCH CLASS:
377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems, appropriate subclasses for a shift register, per se.

Plural parallel output bits:
This subclass is indented under subclass 250. Subject matter wherein the generation produces plural bits of a sequence in parallel.

SEE OR SEARCH THIS CLASS, SUBCLASS:
256 for plural parallel outputs.

Seed value controls:
This subclass is indented under subclass 250. Subject matter wherein seed value is used as an initial value in the generation.

Truly random number:
This subclass is indented under subclass 250. Subject matter wherein the generation produces a random sequence which is not repeated.

Plural parallel outputs:
This subclass is indented under subclass 250. Subject matter wherein the generation produces plural sequences in parallel.

SEE OR SEARCH THIS CLASS, SUBCLASS:
253 for plural parallel output bits.

Function generation:
This subclass is indented under subclass 200. Subject matter wherein a sequence of discrete values is generated to represent a desired waveform.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 8+ and 845+, for electrical hybrid or electrical analog computers which perform the function of function generation.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclasses 100+ for miscellaneous signal converting, shaping, or generating circuits.

Direct digital frequency synthesizer:
This subclass is indented under subclass 270. Subject matter wherein the generation is performed by a digital frequency source capable of producing a multitude of output frequencies from the desired frequency of the waveform.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclasses 105+ for a synthesizer converting, shaping, or generating a nonlinear signal.

Memory used to store waveshape:
This subclass is indented under subclass 270. Subject matter wherein a circuit allows a waveshape to be stored and retrieved for generating the waveform.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclass 106 for waveform or waveshape determinative circuits including stored data.

Counter as source (i.e., input):
This subclass is indented under subclass 270. Subject matter wherein a circuit counts input pulses for producing phase increments as a source.

Linear:
This subclass is indented under subclass 270. Subject matter where the desired waveform is linear.

SEE OR SEARCH THIS CLASS, SUBCLASS:
8 for a hybrid computer providing piece-wise linear synthesis.
852 for analog triangular, sawtooth or ramp function generation.

Circular:
This subclass is indented under subclass 270. Subject matter where the desired waveform represents a circular relationship.

Trigonometric:
This subclass is indented under subclass 270. Subject matter where the desired waveform has trigonometric relationships.

Logarithmic/exponential:
This subclass is indented under subclass 270. Subject matter where the desired waveform is logarithmic or exponential.

SEE OR SEARCH THIS CLASS, SUBCLASS:
851 for analog logarithmic/exponential function generation.

Interpolation/extrapolation:
This subclass is indented under subclass 200. Subject matter for the determination or estimation of a value or values of a function between two known values or of the trend established between two or more known points.

SEE OR SEARCH THIS CLASS, SUBCLASS:
313 for decimation/interpolation in digital filtering.
847 for interpolation/extrapolation in analog piece-wise linear function synthesis.

SEE OR SEARCH CLASS:
318, Electricity: Motive Power Systems, subclass 573 for
interpolation in positional servo systems.

Filtering:
This subclass is indented under subclass 200. Subject matter wherein a computational process or algorithm separates data, signals, or materials in accordance with specified criteria.

SEE OR SEARCH THIS CLASS, SUBCLASS:
819 for analog computer filtering.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclasses 551+ for miscellaneous unwanted signal suppression utilizing an active filter circuit not performing an arithmetic calculation.
702, Data Processing: Measuring, Calibrating, or Testing, subclasses 190+ for signal extraction or separation in measured signal processing.

Tapped delay line:
This subclass is indented under subclass 300. Subject matter wherein a delay line, in which more than two terminal pairs are associated with a single delay channel, is used to provide delayed signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:
425 for correlation using tapped delay line.

Microprocessor:
This subclass is indented under subclass 300. Subject matter wherein the filtering is performed by a microprocessor.

SEE OR SEARCH THIS CLASS, SUBCLASS:
231 for a particular microprocessor used in the multifunctional operation.
510 for a particular microprocessor used in floating point.

SEE OR SEARCH CLASS:
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing (e.g., Processors) subclasses 32+ for particular microprocessor architecture.

Nonlinear (e.g., median, etc.):
This subclass is indented under subclass 300. Subject matter wherein the relationship between the pertinent measures of the input and output signals cannot be adequately described by linear means (e.g., median filter).

SEE OR SEARCH CLASS:
382, Image Analysis, subclass 262 for a median image filter.

Initialization:
This subclass is indented under subclass 300. Subject matter where the filter is placed in a beginning state prior to the actual processing.

Finite arithmetic effect:
This subclass is indented under subclass 300. Subject matter for indication or compensation of an effect arising from the use of operands having a finite length representation.
(1) Note. Included here are such effects as overflow, underflow and oscillation.

SEE OR SEARCH THIS CLASS, SUBCLASS:
496 for floating point compensation for finite word length.

Delta/differential coded:
This subclass is indented under subclass 300. Subject matter in which the samples used in processing are present in the delta or differential coded format.

SEE OR SEARCH CLASS:
341, Coded Data Generation or Conversion, subclasses 76+ for digital conversion to or from a differential code.

Multidimensional data:
This subclass is indented under subclass 300. Subject matter where the data to be processed is multidimensional (e.g., image data).

SEE OR SEARCH CLASS:
382, Image Analysis, subclasses 254+ for image enhancement which may include filtering.

Frequency measurement:
This subclass is indented under subclass 300. Subject matter where frequency determination is accomplished by first removing from a signal corrupting noise which was imposed by a transmission medium.

SEE OR SEARCH CLASS:
324, Electricity: Measuring and Testing, subclass 76.39 for frequency measurement of cyclic current or voltage in general.
702, Data Processing: Measuring, Calibrating, or Testing subclasses 75+ for electrical frequency measurement, per se.

Coherent:
This subclass is indented under subclass 300. Subject matter where a particular frequency is eliminated from a signal.

Frequency detection:
This subclass is indented under subclass 300. Subject matter in which a subset of frequencies from a known set of possible frequencies is determined to be present.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclasses 39+ for discriminating by frequency.

Tone detection:
This subclass is indented under subclass 310. Subject matter where the subset consists of a single frequency.

Decimation/interpolation:
This subclass is indented under subclass 300. Subject matter where the filter deletes from or adds to the samples input to it in a specified regular fashion resulting in a net sampling rate change.

SEE OR SEARCH THIS CLASS, SUBCLASS:
290 for interpolation, per se.

Matched filter type:
This subclass is indented under subclass 300. Subject matter for maximizing the signal-to-noise ratio through the use of filters utilizing correlation techniques.

SEE OR SEARCH CLASS:
375, Pulse or Digital Communications, subclass 343 for pulse demodulation or detection by matched filters.

By convolution:
This subclass is indented under subclass 300. Subject matter in which a convolution technique is utilized to accomplish the filtering.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 420+ for digital convolution, per se.

Having multiplexing:
This subclass is indented under subclass 300. Subject matter where one of a plurality of signals is selected and processed by a given filter or one of a plurality of filters is selected to process a given signal.

Wave:
This subclass is indented under subclass 300. Subject matter in which the filter has elements representing distributed parameters.

SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, subclasses 202+ for analog wave filters.

Lattice:
This subclass is indented under subclass 300. Subject matter in which the filter has four computational or delay elements connected in series to form a closed circuit with two nonadjacent ports serving as the input terminals with the other two ports serving as output terminals.

SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, subclass 169 for analog lattice filters.

Transversal:
This subclass is indented under subclass 300. Subject matter in which feedforward processing of present inputs is utilized.

SEE OR SEARCH THIS CLASS, SUBCLASS:
425 for correlation using tapped delay line.

Recursive:
This subclass is indented under subclass 300. Subject matter in which the present filter output is a function of present inputs and past filter outputs.

Nontime domain:
This subclass is indented under subclass 300. Subject matter where the data when processed is not in the time domain.
(1) Note. Frequently this data is in the frequency domain.

Adaptive:
This subclass is indented under subclass 300. Subject matter where the transfer function of the filter is automatically changed as a function of the input signal.

Equalizer:
This subclass is indented under subclass 321. Subject matter where adaptive compensation for transmission medium noise imposition is performed.

SEE OR SEARCH CLASS:
375, Pulse or Digital Communications, subclasses 229+ for equalizers in a digital communications system.

Transform:
This subclass is indented under subclass 200. Subject matter wherein the digital calculation performs a transformation of a given representation of a data signal to another representation without loss of information by an orthogonal transformation.

SEE OR SEARCH CLASS:
704, Data Processing: Speech Signal Processing, Linguistics, Language Translation, and Audio Compression/Decompression, subclasses 200+ for speech signal processing.

Multidimensional:
This subclass is indented under subclass 400. Subject matter including a specific apparatus which is used for computing an n-dimensional transform of an input signal with n greater or equal to two.

Discrete Cosine Transform (i.e., DCT):
This subclass is indented under subclass 400. Subject matter wherein the transformation performed is a Discrete Cosine Transform.

Fourier:
This subclass is indented under subclass 400. Subject matter wherein the transformation performed is a mathematical operation which decomposes a time varying signal into its complex frequency components (amplitude and the phase or real and imaginary components).

SEE OR SEARCH CLASS:
382, Image Analysis, subclass 280 for a Fourier transform performed on image data.

Fast Fourier Transform (i.e., FFT):
This subclass is indented under subclass 403. Subject matter wherein the transformation performed is a Fast Fourier Transform.

SEE OR SEARCH THIS CLASS, SUBCLASS:
405 for Discrete Fourier Transform.

Discrete Fourier Transform (i.e., DFT):
This subclass is indented under subclass 403. Subject matter wherein the transformation performed is a Discrete Fourier Transform.

SEE OR SEARCH THIS CLASS, SUBCLASS:
404 for Fast Fourier Transform.

Pipeline:
This subclass is indented under subclass 403. Subject matter wherein the transformation is performed in a pipeline where the output of one task is input to another until a desired sequence of tasks has been carried out.

SEE OR SEARCH THIS CLASS, SUBCLASS:
233 for multifunctional operation performed in a particular pipeline.
508 for floating point performed in a particular pipeline.
521 for arithmetical pipeline operation in general.
631 for multiple digit binary multiplication performed in a particular pipeline.

Systolic:
This subclass is indented under subclass 403. Subject matter
wherein the transformation is performed by a specific apparatus having an array of computational elements where data is transferred synchronously between nearest neighbor elements.

SEE OR SEARCH THIS CLASS, SUBCLASS:
509 for a particular systolic array used in floating point.
522 for a particular systolic array used in an arithmetical operation.

SEE OR SEARCH CLASS:
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing ( e.g., Processors) subclass 19 for systolic array processor architecture.

Radix greater than two:
This subclass is indented under subclass 403. Subject matter wherein a specific apparatus is used for computing an n-radix Fourier Transform with n greater than two.

Butterfly circuit:
This subclass is indented under subclass 403. Subject matter wherein a specific apparatus performs a complex multiplication and a complex addition or subtraction.

Walsh:
This subclass is indented under subclass 400. Subject matter wherein the transformation performed is a Walsh Transform.

SEE OR SEARCH CLASS:
382, Image Analysis, subclass 281 for image transformation or processing using a Walsh Transform.

Convolution:
This subclass is indented under subclass 200. Subject matter which the convolution integral is evaluated in a digital fashion.
(1) Note. Frequently, the output of a system is determined by convolving the system input with the system impulse response.

SEE OR SEARCH THIS CLASS, SUBCLASS:
5 for hybrid computer convolution.
315 for convolution in digital filtering.
subclasses 813+ for analog computer convolution.

SEE OR SEARCH CLASS:
382, Image Analysis, subclass 279 for convolution in image preliminary processing or transformation.

Cyclic/circular:
This subclass is indented under subclass 420. Subject matter where the convolution integral of a and b, two series of discrete values, is found by performing a transform operation on a and b (producing A and B respectively) and then performing the inverse transform operation on the product of A and B.

Correlation:
This subclass is indented under subclass 200. Subject matter where the particular function determines the degree of correspondence between two series of discrete values by digitally evaluating the correlation integral.

SEE OR SEARCH THIS CLASS, SUBCLASS:
5 for hybrid computer correlation.
subclasses 813+ for analog computer correlation.

SEE OR SEARCH CLASS:
382, Image Analysis, subclass 278 for correlation in image preliminary processing or transformation.

Single bit data:
This subclass is indented under subclass 422. Subject matter in which the discrete values have a one bit representation.

Multidimensional data:
This subclass is indented under subclass 422. Subject matter in which at least one series of discrete values is multidimensional (e.g., image data).

SEE OR SEARCH THIS CLASS, SUBCLASS:
814 for analog correlation of multidimensional data.

SEE OR SEARCH CLASS:
382, Image Analysis, subclass 278 for correlation used in image transformation or prerecognition processing.

Using tapped delay line:
This subclass is indented under subclass 422. Subject matter where the outputs from successive stages of a digital delay element are utilized.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 301+ for related structure utilized in a filtering environment.
818 for analog correlation having a tapped delay line.

Autocorrelation:
This subclass is indented under subclass 422. Subject matter in which both series of discrete values are from a single source.

Evaluation of trigonometric function:
This subclass is indented under subclass 200. Subject matter wherein the particular function performed is the processing of a signal either to determine a trigonometric relationship or to operate on a signal in accordance with a trigonometric relationship.

SEE OR SEARCH THIS CLASS, SUBCLASS:
276 for waveform generation having trigonometric relationships.
811 for evaluation of trigonometric function by analog computer.

Vector resolver:
This subclass is indented under subclass 440. Subject matter wherein the signal is a vector and the operation is determining the vector components.

SEE OR SEARCH THIS CLASS, SUBCLASS:
809 for a vector resolver using analog computer.

Coordinate conversion:
This subclass is indented under subclass 200. Subject matter wherein the particular function performed is conversion of coordinates from one coordinate system to another (e.g., rectangular to polar).
(1) Note. The calculation of the change in coordinates resulting from a translation or rotation of a reference coordinate system is included in this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:
809 for a coordinate conversion using analog computer.

Differentiation:
This subclass is indented under subclass 200. Subject matter for differentiation of at least one of a plurality of input signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:
6 for hybrid computer differentiation.
822 for analog differentiation.

Integration:
This subclass is indented under subclass 200. Subject matter for the integration of a sequence of discrete values of an input signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:
6 for hybrid computer integration.
subclasses 823+ for analog integration.

Averaging:
This subclass is indented under subclass 200. Subject matter for determining the average of a sequence of discrete values.

SEE OR SEARCH THIS CLASS, SUBCLASS:
805 for analog computer averaging.

SEE OR SEARCH CLASS:
702, Data Processing: Measuring, Calibrating, or Testing, subclass 194 for averaging in measured signal noise suppression.

Solving equation:
This subclass is indented under subclass 200. Subject matter wherein the specialized function performed is to solve an equation.
(1) Note. Excluded are arithmetical operations.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 490+ for digital arithmetical operations.

Arithmetical operation:
This subclass is indented under subclass 200. Subject matter wherein numerical quantities form the elements of the calculation, including the fundamental operations of arithmetic (addition, subtraction, multiplication, comparison, and division).

Residue number:
This subclass is indented under subclass 490. Subject matter wherein the numerical digits are in the residue number system.

SEE OR SEARCH THIS CLASS, SUBCLASS:
532 for residue code error detection or correction.

Galois field:
This subclass is indented under subclass 490. Subject matter where the arithmetical operations are performed on a 2 m element finite arithmetic field.

Multi-valued:
This subclass is indented under subclass 490. Subject matter where the arithmetical operations are performed with multi-valued operands.

Incremental mode:
This subclass is indented under subclass 490. Subject matter wherein the numerical digits represent a change in numbers as opposed to whole number representation.

SEE OR SEARCH CLASS:
375, Pulse or Digital Communications, subclasses 247+ for delta modulation.

Floating point:
This subclass is indented under subclass 490. Subject matter wherein the numerical digits are expressed in terms of a bounded number (mantissa) and a scale factor (characteristic or exponent) consisting of a power of the number base.

Compensation for finite word length:
This subclass is indented under subclass 495. Subject matter wherein the operation results in a word modification in length due to insufficient representation of using the fixed word length of the arithmetic system.

SEE OR SEARCH THIS CLASS, SUBCLASS:
306 for finite arithmetic effect in digital filtering.
subclasses 550+ for compensation for finite word length used in arithmetical operations.

Round off or truncation:
This subclass is indented under subclass 496. Subject matter wherein the modification is a deletion of one or more of the least significant digits and an adjustment of the more significant digits in accordance with some specific rule.

SEE OR SEARCH THIS CLASS, SUBCLASS:
551 for round off or truncation in arithmetical operations.

Overflow or underflow:
This subclass is indented under subclass 496. Subject matter wherein the modification is necessary because the word is either too large or too small to be represented using the fixed word length.

SEE OR SEARCH THIS CLASS, SUBCLASS:
552 for overflow or underflow used in arithmetical operations.

Sticky bit:
This subclass is indented under subclass 496. Subject matter wherein the modification is based on whether or not a number of least significant digits contains a one.

Evaluation of root:
This subclass is indented under subclass 495. Subject matter wherein the operation performed is the determination of a root.

SEE OR SEARCH THIS CLASS, SUBCLASS:
605 for evaluation of root by digital arithmetic operations.
807 for analog evaluation of root.

Multiplication followed by addition:
This subclass is indented under subclass 495. Subject matter wherein the operation performed is multiplication followed by an addition.

SEE OR SEARCH THIS CLASS, SUBCLASS:
523 for performing a multiplication followed by addition in arithmetic operations.

Reciprocal:
This subclass is indented under subclass 495. Subject matter wherein the operation performed is the determination of the reciprocal.

Multiplication:
This subclass is indented under subclass 495. Subject matter wherein the operation performed is multiplication.

SEE OR SEARCH THIS CLASS, SUBCLASS:
7 for hybrid computer multiplication.
subclasses 620+ for performing a multiplication in digital arithmetical operations.
subclasses 835+ for analog multiplication.

Division:
This subclass is indented under subclass 495. Subject matter wherein the operation performed is division.

SEE OR SEARCH THIS CLASS, SUBCLASS:
7 for hybrid computer division.
subclasses 650+ for division by digital computer.
844 for division by analog computer.

Addition or subtraction:
This subclass is indented under subclass 495. Subject matter wherein the operation performed is addition or subtraction.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 670+ for addition/subtraction by digital computer.

Feedback:
This subclass is indented under subclass 495. Subject matter wherein the operation is effected by the return of a portion of the output to its input.

SEE OR SEARCH THIS CLASS, SUBCLASS:
632 for feeding back partial product to complete the multiple digit binary multiplication.

Parallel:
This subclass is indented under subclass 495. Subject matter wherein the operation is effected by the use of two or more processors running simultaneously.

Pipeline:
This subclass is indented under subclass 495. Subject matter wherein the operation is effected by passing the output of one task as input to another until a desired sequence of tasks has been carried out.

SEE OR SEARCH THIS CLASS, SUBCLASS:
233 for multifunctional operation performed in a particular pipeline.
406 for Fourier transformation performed in a particular pipeline.
521 for arithmetical pipeline operation in general.
631 for multiple digit binary multiplication performed in a particular pipeline.

Systolic:
This subclass is indented under subclass 495. Subject matter wherein the operation is effected by a specific apparatus using an array of computational elements where data is transferred synchronously between nearest neighbor elements.

SEE OR SEARCH THIS CLASS, SUBCLASS:
407 for a particular systolic array used in a Fourier transform.
522 for a particular systolic array used in an arithmetical operation.

SEE OR SEARCH CLASS:
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing (e.g., Processors), subclass 19 for systolic array processor architecture.

Microprocessor:
This subclass is indented under subclass 495. Subject matter wherein the operation is effected by a microprocessor.

SEE OR SEARCH THIS CLASS, SUBCLASS:
231 for a particular microprocessor used in a multifunctional operation.
303 for a particular microprocessor used in filtering.

SEE OR SEARCH CLASS:
712, Electrical Computers and Digital Processing Systems:
Processing Architectures and Instruction Processing ( e.g., Processors) subclasses 32+ for particular microprocessor architecture.

Complex number format:
This subclass is indented under subclass 495. Subject matter wherein the numerical digits have a real part and an imaginary part.

SEE OR SEARCH THIS CLASS, SUBCLASS:
subclasses 622+ for using complex number format in a multiplication operation.

Logarithmic format:
This subclass is indented under subclass 495. Subject matter wherein the numerical digits which constitute an operand represented by the exponent to which a base number must be raised to produce the operand.

SEE OR SEARCH THIS CLASS, SUBCLASS:
517 for logarithmic format in arithmetical operations.

SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, subclasses 350+ for miscellaneous circuits providing a logarithmic function of an input signal.

Variable length or precision:
This subclass is indented under subclass 495. Subject matter wherein the numerical digits which constitute an operand are of selectable length or provide more detail.

SEE OR SEARCH THIS CLASS, SUBCLASS:
518 for variable length in digital arithmetical operations.

Matrix array:
This subclass is indented under subclass 495. Subject matter wherein the data is operated on by elements arranged in rows and columns.

SEE OR SEARCH THIS CLASS, SUBCLASS:
520 for a arithmetic matrix array operation in general.
607 for a particular multiplication of matrices.

SEE OR SEARCH CLASS:
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing (e.g., Processors) subclasses 2+ for vector processor architecture.

Logarithmic format:
This subclass is indented under subclass 490. Subject matter where an operand is represented by the exponent to which a base number must be raised to produce the operand.

SEE OR SEARCH THIS CLASS, SUBCLASS:
512 for logarithmic format in floating point.

Variable length:
This subclass is indented under subclass 490. Subject matter wherein the number of numerical digits that represent numbers are of differing length.

SEE OR SEARCH THIS CLASS, SUBCLASS:
513 for variable length or precision in floating point.

Negative radix:
This subclass is indented under subclass 490. Subject matter wherein the numerical digits are represented in negative radix format.

Matrix array:
This subclass is indented under subclass 490. Subject matter wherein the data is operated on by elements arranged in rows and columns.
(1) Note. Matrix array processing of multiplication or division per se is classified elsewhere.

SEE OR SEARCH THIS CLASS, SUBCLASS:
514 for a particular matrix array with floating point.
607 for multiplication of matrices.
subclasses 620+ for multiplication which may incorporate a matrix array.
subclasses 650+ for division which may incorporate a matrix array.

SEE OR SEARCH CLASS:
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing (e.g., Processors) subclasses 2+ for vector processor architecture.

Pipeline:
This subclass is indented under subclass 490. Subject matter wherein the operation is performed in a pipeline by passing the output of one task as input to another until a desired sequence of tasks has been carried out.
(1) Note. Pipeline processing of multiplication or division per se is classified elsewhere.

SEE OR SEARCH THIS CLASS, SUBCLASS:
233 for multifunctional operation performed in a particular
pipeline.
406 for Fourier transform performed in a particular pipeline.
508 for floating point performed in a particular pipeline.
subclasses 620+ for multiplication which may incorporate pipeline processing, particularly
631 for multiple digit binary multiplication performed in a particular pipeline.
subclasses 650+ for division which may incorporate pipeline processing.

Systolic:
This subclass is indented under subclass 490. Subject matter wherein the operation is effected by a specific apparatus using an array of computational elements where data is transferred synchronously between nearest neighbor elements.
(1) Note. Systolic processing of multiplication or division per se is classified elsewhere.

SEE OR SEARCH THIS CLASS, SUBCLASS:
407 for a particular systolic array used in a Fourier transform.
509 for a particular systolic array used in floating point.
subclasses 620+ for multiplication which may incorporate systolic processing.
subclasses 650+ for division which may incorporate systolic processing.

SEE OR SEARCH CLASS:
712, Electrical Computers and Digital Processing Systems: Processing Architectures and Instruction Processing ( e.g., Processors) subclass 19 for systolic array processor architecture.

Multiplication followed by addition (i.e., x*y+z):
This subclass is indented under subclass 490. Subject matter wherein the operation performed is a multiplication followed by an addition.

SEE OR SEARCH THIS CLASS, SUBCLASS:
501 for performing a multiplication followed by addition with floating point.

Multiple parallel operations:
This subclass is indented under subclass 490. Subject matter including two or more operations in which numerical digits are transmitted simultaneously on separate lines.

Status condition/flag generation or use:
This subclass is indented under subclass 490. Subject matter where an indicator of the present data processing status is generated or used to select from a plurality of future processing paths.

SEE OR SEARCH THIS CLASS, SUBCLASS:
306 for flag generation or use in a digital filtering finite arithmetic effect environment.

Error detection or correction:
This subclass is indented under subclass 490. Subject matter with means identifying a malfunction in the operation of the apparatus or the result produced.

SEE OR SEARCH CLASS:
714, Error Detection/Correction and Fault Detection/Recovery, appropriate subclass for systems which test for malfunction in nonarithmetical operations.