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GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (measuring, testing G01R; generators adapted for electrophonic musical instruments G10H; Speech synthesis G10L; masers, lasers H01S; dynamo-electric machines H02K; power inverter circuits H02M; by using pulse techniques H03K; automatic control of generators H03L; starting, synchronisation or stabilisation of generators where the type of generator is irrelevant or unspecified H03L; generation of oscillations in plasma H05H)
Definition statement
This subclass/group covers:

Generation of oscillations in a non-switching manner, i.e. by harmonic oscillators providing sinusoidal signals.

Generation without frequency changing

by means of amplification and feedback; negative resistance

by means of transit-time tubes; electron-beam tubes

by shock-exciting; Hall effect; radiation source and detectors

Generation with frequency changing

by multiplication or division of a signal

by combining unmodulated signals

Particularities of generated oscillations

Swept-over frequency range; multifrequency; multiphase; noise

Relationship between large subject matter areas

This subclass covers circuits and methods dedicated to achieve sinusoidal oscillations by analogue means. This is to be distinguished from circuits and methods intended to generate edge shaped periodic signals (pulses, digital clocks) that are to be classified elsewhere (see references below).

This subclass covers generic oscillators that are generally applicable to any application. Oscillators adapted for a specific application or apparatus (e.g. for a specific measurement device or radar system) and which are not generally applicable should generally be classified in the groups for that application.

References relevant to classification in this subclass
This subclass/group does not cover:
Generators adapted for electrophonic musical instruments
Masers, lasers
Generation of oscillations in plasma
Informative references
Attention is drawn to the following places, which may be of interest for search:
Measuring, testing
Digital function generators
Generating clock signals
Speech synthesis
Dynamo-electric machines
Power inverter circuits
Amplifiers
Resonant circuits, resonators
Tuning of resonators
Oscillators using pulse techniques
Automatic control, starting, synchronisation, or stabilisation of generators of electronic oscillations
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Elements that operate in non-switching manner
Gain element not driven to saturation; No full swing operation as in digital circuit
Synonyms and Keywords

In patent documents the following abbreviations are often used:

VCO
Voltage Controlled Oscillator
Q factor
Quality factor of resonator
Quadrature oscillators
Oscillators generating two signals with same frequency shifted by 90°
Varactor
Varicap diode, varactor diode, variable capacitance diode, variable reactance diode: tuning diode with variable capacitance
Details
Definition statement
This subclass/group covers:

This main group covers:

Details regarding the means for making the frequency variable

Structural details of power oscillators

Reduction of undesired oscillations

Relationship between large subject matter areas

This main group is orthogonal to the other groups within H03B, i.e. multiple classification in H03B 1/00 and in H03B 5/00 to H03B 29/00 is made when appropriate.

References relevant to classification in this main group
This subclass/group does not cover:
Features of generators for heating by electromagnetic fields
Informative references
Attention is drawn to the following places, which may be of interest for search:
Structural details of waveguide cavity resonators
Structural details of electromechanical resonators
Details of transmitters
Structural details of power oscillators, e.g. for heating [N: (construction of transmitters H04B; features of generators for heating by electromagnetic fields H05B 6/00 )
Informative references
Attention is drawn to the following places, which may be of interest for search:
Features of generators for heating by electromagnetic fields
Generation of oscillations using amplifier with regenerative feedback from output to input (H03B 9/00H03B 15/00 take precedence)
Definition statement
This subclass/group covers:

This main group covers:

Oscillators with feedback comprising in particular

- LC tanks

- RC or RL tuned circuits

- distributed reactances (e.g. striplines, cavity resonators, magneto-sensitive resonators)

- electromechanical resonators (e.g. piezo-electric resonators, magneto-strictive resonators)

Compensation of variations in parameters affecting the output frequency or amplitude of feedback oscillators (such as power supply, load or temperature) as far as a modification of the generator itself is concerned

Starting of feedback oscillators as long as a modification of the generator itself is concerned

References relevant to classification in this main group
This subclass/group does not cover:
Generation of oscillations using galvano-magnetic devices
Generation of oscillations using transit-time effects
Informative references
Attention is drawn to the following places, which may be of interest for search:
Waveguide cavity resonators
Constructional details of electromechanical resonators and their holders and supports
Ring oscillators
External temperature control
Starting of generators if no features within the oscillator are concerned
Automatic control of amplitude of generators
Automatic control of frequency of generators
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Connection via bridge circuit to closed ring
The oscillation loop is a closed ring including a bridge circuit, e.g.
FR1488980, C Morel
Synonyms and Keywords

In patent documents the following abbreviations are often used:

AT cut
Particular angle of crystal cut
BAW resonator
Bulk acoustic wave resonator
SAW resonator
Surface acoustic wave resonator
Butler type oscillator
Colpitts (or Clapp) type oscillator with a series resonant crystal inserted in series between the emitter and the rest of the tank circuit.
Kurt Wessendorf, Sandia Nat. Lab.
Clapp type oscillator
Refinement of a Colpitts oscillator including an additional capacitor (C0) in series with the inductor. Series tuned version of the Colpitts oscillator.
Colpitts type oscillator
Oscillator with feedback via a capacitive voltage divider (C1,C2). Can be LC or may include another resonator (e.g. a crystal) instead of or in addition to the inductor (L). Can also be balanced, e.g. US2006097799 P.P. Guebels :
Hartley
LC oscillator with feedback via an inductive voltage divider.
Pierce type oscillator
Oscillator comprising an amplifier, a crystal resonator connected in series in its feedback path and load capacitors at the input and output.
Wien bridge oscillator
Positive gain amplifier with a bridge circuit comprising a series RC circuit and a parallel RC circuit to provide positive feedback.
Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
Definition statement
This subclass/group covers:

US20100102892, J. Arai

Rb(t): Temperature sensing resistor within the oscillator, considered as a "modification of the generator" falling within the scope of H03B 5/04.

US2009261917, M. Taghivand Et al.: temperature compensating varactor receives control signal from outside the oscillator. NOT to be classified in H03B 5/04, but instead in H03L 1/023, because it is not a "modification of the generator" itself.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Stabilisation of generator output against variations of temperature
active element in amplifier being vacuum tube (H03B 5/14 takes precedence)
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element comprising lumped inductance and capacitance and active element in amplifier being vacuum tube.

References relevant to classification in this subgroup
This subclass/group does not cover:
Frequency-determining element connected via bridge circuit to closed ring around which signal is transmitted
active element in amplifier being semiconductor device (H03B 5/14 takes precedence)
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element comprising lumped inductance and capacitance and active element in amplifier being semiconductor device. The majority of transistor based LC oscillators are classified here or in the subgroups.

References relevant to classification in this subgroup
This subclass/group does not cover:
Frequency-determining elements connected via bridge circuit to closed ring around which signal is transmitted
Oscillators with a lumped LC resonant circuit and the active element being a semiconductor device, but where the active element provides a negative resistance instead of using regenerative feedback.
Special rules of classification within this subgroup

Documents falling under H03B 5/12 should generally receive multiple classifications from the subgroups and all relevant group symbols should be applied. Generally, it is required to apply at least one of the subgroups H03B 5/1203 or H03B 5/1206 to define the amplifier configuration, at least one of the subgroups H03B 5/1228 and H03B 5/1231 to define the transistor types and possibly also one of the subgroups H03B 5/1234 or H03B 5/1237 to define any variable parameters.

[N: the amplifier being a single transistor (H03B 5/1206 to H03B 5/1228 take precedence)]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element in the amplifier being a single transistor.

References relevant to classification in this subclass
This subclass/group does not cover:
Any oscillators with more than one transistor for amplification
Special rules of classification within this subclass

The single-transistor-amplifier should be the amplifier that provides the gain in the oscillation loop. Other amplifiers, e.g. connected after the oscillator and outside the loop are not considered when deciding if a single transistor is used. Auxiliary transistors that are provided for a purpose other than amplification, e.g. as a current source or a switch, are also not counted. Hence any oscillator with a single amplification transistor should be classified here. In general further subgroup symbols under H03B 5/12 will also be added in combination with this one.

Example:

WO0211277, Y.M. Yeong

Single transistor 22 used for amplification in the oscillation loop.

US2008309415, T. Aramata

The circuit contains 5 transistors, but two (Tr4 and Tr5) are used for switching and one (Tr1) is a buffer at the output, these are therefore outside of the oscillation loop and not used for providing gain. The remaining two are providing gain, but in separate oscillation loops. This therefore effectively shows two oscillators, each with a single amplification transistor and is classified in H03B 5/1203.

[N: using multiple transistors for amplification (H03B 5/1228 takes precedence)]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element in the oscillation amplifier using more than one transistor to provide the gain.

Particular configurations of the multiple amplification transistors:

- Oscillators with differential amplifiers and no cross coupling

- Cross coupled oscillators

- Oscillators with differential amplifiers and cross coupling

- Balanced oscillators

- Oscillators with multistage amplifiers

- Oscillators with multiple amplifiers connected in parallel

Special rules of classification within this subgroup

This group and its subgroups are intended to contain oscillators where multiple transistors are used to provide the gain for a single oscillation loop. For example, differential amplifiers, multistage amplifiers, multiple amplifiers connected in parallel and to a common resonator are all to be found here or in subgroups. Other amplifiers, e.g. connected after the oscillator and outside the loop are not considered for determination whether multiple transistors are present. Auxiliary transistors that are provided for a purpose other than amplification, e.g. as a current source or a switch, are also not counted, so an oscillator comprising a single amplification transistor and a further transistor for switching off the oscillator, would NOT be classified here, but instead as a single transistor in H03B 5/1203.

[N: the amplifier having two current paths operating in a differential manner and a current source or degeneration circuit in common to both paths e.g. a long-tailed pair]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element in the oscillation amplifier for oscillation using more than one transistor and having two current paths conducting a differential current, i.e. being a differential amplifier. A current source or degeneration circuit in common to both paths provides current which is then split between the two current paths.

Example:

US2007182503, J.G. Petrofsky

Q10L and Q10R are a differential pair and Q16 is the common current source of the differential amplifier. C12 and L12 make the resonator. There is no cross coupling between the transistors of the differential pair.

References relevant to classification in this group
This subclass/group does not cover:

This group does not cover :

Oscillators where the amplifier is a cross-coupled transistor pair
[N: the amplifier comprising a pair of transistors, an output terminal of each being connected to an input terminal of the other, e.g. a cross-coupled pair]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element in the oscillation amplifier for oscillation comprising a pair of cross-coupled transistors.

Special rules of classification within this group

This group contains any oscillators where the amplifier contains a pair of transistors the output of each one being connected to the input of the other. The normal case is a cross-coupled emitter or source-coupled pair, but other configurations are also possible.

Example:

US2008258827, M. Tsai

LC oscillator comprising a cross-coupled source-coupled pair of transistors.

[N: and a current source or degeneration circuit in common to both transistors of the pair e.g. a cross-coupled long-tailed pair]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element in the oscillation amplifier for oscillation comprising a pair of cross-coupled transistors and a current source or degeneration circuit in common to both paths.

Any oscillators where the amplifier contains a pair of transistors the output of each one being connected to the input of the other and further having a common current source (or degeneration circuit). The current source or degeneration circuit in common to both transistors provides current which is then split between the current paths of the two transistors, hence these are LC oscillators using cross coupled differential amplifiers.

Example:

or

both from US2008258827, M. Tsai

Circuits 14 and 26 act as a current source in common to both transistors of the respective cross-coupled pair and building a differential amplifier.

[N: the generator being of the balanced type]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element in the oscillation amplifier comprising multiple transistors and the generator being of the balanced type.

Here a balanced oscillator is not considered to include the differential type with a cross coupled transistor pair. Instead balanced oscillators are considered to include configurations where at least two amplifiers operate with separate oscillation circuits which are however coupled in such a way as to provide a balanced output. Often a single resonant circuit is coupled between both amplifiers.

Example:

US5012205, W.J. Howell

Transistors 12 and 14 build a balanced type oscillator.

WO2004075394, H. Veenstra

Both two-stage emitter follower circuits provide gain to the single resonant circuit, but are coupled at opposite sides of it to provide a balanced output.

US2008129392, J.Y. Lee

Two colpitts type oscillators coupled in a balanced configuration

[N: the amplifier comprising multiple stages connected in cascade]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the oscillation amplifier comprising multiple stages in cascade.

Any oscillators where the amplifier contains multiple stages in cascade. This is not considered to include the case where a differential pair is cross coupled (which is instead considered to be a single differential stage) .

Example:

EP1753136, Y. ARAYASHIKI

Two amplifier stages 22a and 22b in a single loop.

[N: comprising multiple amplifiers connected in parallel]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the oscillation amplifier comprising multiple amplifier circuits in parallel.

This subgroup contains any oscillators where the amplifier contains multiple amplifier circuits in parallel, i.e. the inputs of each amplifier are connected together, as are the outputs. It also includes circuits where some or all of the parallel amplifier circuits are or can be switched in or out of the circuit, for example to provide multiple gain levels or for startup. It does not include cases where separate amplifiers are connected to different resonant circuits and therefore not in parallel.

Example:

US2009289732, D. MIYASHITA

An amplifier consisting of transistors M3 and M4 can be switched in parallel with M1, M2 to provide different gain levels.

[N: the amplifier comprising one or more field effect transistors]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element in the amplifier comprising at least one FET.

References relevant to classification in this group
This subclass/group does not cover:
Oscillators where a variable capacitance is provided by a FET transistor
Special rules of classification within this group

The group includes oscillator circuits where the amplifier of the oscillation loop comprises at least one FET. Where the amplifier includes both FET and bipolar transistors, also the classification H03B 5/1231 should be applied. This group is intended to indicate only the type of transistors used in the amplifier of the oscillation loop, but those transistors can be used to provide the gain or for other auxiliary purposes, e.g. for biasing. Hence an amplifier using one transistor type for amplification and another for biasing should receive both group symbols H03B 5/1228 and H03B 5/1231. This class is not applied to classify transistor types used at other places in the circuit, for example buffer circuits at the output and therefore not inside the oscillation loop. It is also not used to distinguish transistor types used in the oscillation loop but not part of the amplifier - for example the type of transistors providing a voltage dependent capacitance are classified in the groups H03B 5/125 and H03B 5/1253.

[N: the amplifier comprising one or more bipolar transistors]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element in the amplifier comprising at least one bipolar transistor.

References relevant to classification in this subgroup
This subclass/group does not cover:
Oscillators where a variable capacitance is provided by a bipolar transistor
Special rules of classification within this subgroup

The subgroup includes oscillator circuits where the amplifier of the oscillation loop comprises at least one bipolar transistor. Where the amplifier includes both FET and bipolar transistors, also the classification H03B 5/1228 should be applied. This group is intended to indicate only the type of transistors used in the amplifier of the oscillation loop, but those transistors can be used to provide the gain or for other auxiliary purposes, e.g. for biasing. Hence an amplifier using one transistor type for amplification and another for biasing should receive both group symbols H03B 5/1228 and H03B 5/1231. This class is not applied to classify transistor types used at other places in the circuit, for example buffer circuits at the output and therefore not inside the oscillation loop. It is also not used to distinguish transistor types used in the oscillation loop but not part of the amplifier - for example the type of transistors providing a voltage dependent capacitance are classified in the groups H03B 5/125 and H03B 5/1253.

[N: and comprising means for varying the output amplitude of the generator]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element being a semiconductor device (e.g. a transistor) and further having means providing a variable output amplitude.

References relevant to classification in this subgroup
This subclass/group does not cover:
Varying the amplitude of the oscillator in dependence on the frequency
Automatic control of the amplitude (voltage, current or power) of generators.
[N: and comprising means for varying the output frequency of the generator]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element being a semiconductor device (e.g. a transistor) and the frequency being tunable.

Particular aspects of the frequency tuning:

- Tuning by means of voltage dependent capacitors

- Tuning by means of variable inductors

- Tuning by means of switched components

- Tuning by a control current

- Controlling other parameters in dependence on the frequency

- Means for achieving particular tuning characteristics

Informative references
Attention is drawn to the following places, which may be of interest for search:
Frequency modulation by means of variable impedance
Tuning in general
Automatic control of the frequency or phase of generators, e.g. by a PLL.
[N: the frequency being controlled by a control current i.e. current controlled oscillators]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element being a semiconductor device (e.g. a transistor) and the frequency being tuned by a control current.

All types of current controlled oscillators are classified here, regardless of whether the control current is applied to a current dependent inductor or capacitor or whether it is applied elsewhere (e.g. as a bias to an active element) where a frequency tuning is thereby achieved. Additional group symbols should be applied where appropriate, e.g. typically H03B 5/124, H03B 5/1256 or their subgroups.

[N: having means for achieving a desired tuning characteristic e.g. linearising the frequency characteristic across the tuning voltage range]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element being a semiconductor device (e.g. a transistor), the frequency being tuned and additionally having means for achieving a desired tuning characteristic.

Typically the desired tuning characteristic is a linear control voltage to frequency characteristic, but this subgroup covers any measures to obtain any tuning characteristic. For example, stepwise linear functions or higher and subgroupser tuning sensitivity (which amount to a steeper/less steep tuning curve) are also covered.

[N: and also varying another parameter in dependence on the frequency]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element being a semiconductor device (e.g. a transistor), the frequency being tuned and another parameter also being varied (continuously or in steps) in dependence on the oscillation frequency.

Typical examples for documents to be classified here or in the subgroups are:

- where the gain is controlled such that the output amplitude remains constant over the frequency range, which would be classified in the subgroup H03B 5/1278 and depending on the specific implementation perhaps also in H03B 5/1281 or H03B 5/129.

- where the oscillator comprises a filter to select a specific harmonic component of the fundamental resonant frequency and that frequency is tuned in tandem with the tuning of the resonant circuit, which would be classified in H03B 5/1284

[N: the feedback circuit comprising a transformer]
Definition statement
This subclass/group covers:

Oscillators using an amplifier with regenerative feedback and a frequency-determining element comprising lumped inductance and capacitance, the active element being a semiconductor device (e.g. a transistor) and further having a transformer in the feedback path.

[N: the active element in the amplifier being a vacuum tube (see provisionally also H03B 5/1835 )]
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback and frequency-determining element comprising distributed inductance and capacitance and being a coaxial resonator and the active element in the amplifier being a vacuum tube.

References relevant to classification in this subgroup
This subclass/group does not cover:
Active elements in the amplifier being a vacuum tube
[N: the frequency-determining element being a cavity resonator]
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback and the frequency-determining element being a cavity resonator.

Physical details of cavity resonators that can be regarded as distributed inductances.

Example of an oscillator with cavity resonator:

FR2699346, L. Fourdan

1: cavity

Informative references
Attention is drawn to the following places, which may be of interest for search:
Cavity resonators
[N: the frequency-determining element being a strip line resonator (H03B 5/1805, H03B 5/1817H03B 5/1864 and H03B 5/1882 take precedence)]
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback and the frequency-determining element being a strip-line resonator.

References relevant to classification in this subgroup
This subclass/group does not cover:
Frequency-determining elements being a coaxial resonator
Frequency-determining elements being a cavity resonator
Frequency-determining elements being a dielectric resonator
Frequency-determining element being a magnetic-field sensitive resonator
Special rules of classification within this group

Resonators comprising a strip-line and another of the resonator types defined in the other subgroups of H03B 5/18, i.e. coaxial, cavity, dielectric or field sensitive resonators, are classified according to the other resonator, i.e. not in H03B 5/1841.

[N: the active element in the amplifier being a semiconductor device]
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback and the frequency-determining element being a strip-line resonator and the active element in the amplifier being a semiconductor device.

Example:

EP1117177, T. Tanemura

The resonance circuit (8) comprises a microstrip line (10); the active element in the amplifier is a semiconductor device (1).

[N: the semiconductor device being a field-effect device]
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback and the frequency-determining element being a strip-line resonator and the active element in the amplifier being a field-effect device.

Example:

EP1993199, S. El Rair

The resonance circuit comprises microstrip lines (403, 407, 411, 415, ); the semiconductor device in the amplifiers (405, 409, 413) are field effect transistors.

active element in amplifier being vacuum tube (H03B 5/26 takes precedence)
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback and frequency-determining element comprising resistance and either capacitance or inductance and active element in amplifier being vacuum tube.

References relevant to classification in this subgroup
This subclass/group does not cover:
Frequency-determining elements being part of bridge circuit in closed ring around which signal is transmitted; frequency-determining elements being connected via a bridge circuit to such a closed ring
active element in amplifier being semiconductor device (H03B 5/26 takes precedence)
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback and frequency-determining element comprising resistance and either capacitance or inductance and active element in amplifier being semiconductor device.

Example:

US2010231311, S.W. Park

Example of an RC oscillator

References relevant to classification in this subgroup
This subclass/group does not cover:
Frequency-determining elements being part of bridge circuit in closed ring around which signal is transmitted; frequency-determining element being connected via a bridge circuit to such a closed ring
frequency-determining element being part of bridge circuit in closed ring around which signal is transmitted; frequency-determining element being connected via a bridge circuit to such a closed ring, e.g. Wien-Bridge oscillator, parallel-T oscillator
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback and frequency-determining element comprising resistance and either capacitance or inductance and frequency-determining element being part of bridge circuit in closed ring around which signal is transmitted; frequency-determining element being connected via a bridge circuit to such a closed ring. Most commonly these are Wien Bridge type oscillators.

Example:

EP1520339, K. Panzer

RC oscillator in Wien-bridge configuration

being a piezo-electric resonator (selection of piezo-electric material H01L 41/00 )
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element being a piezo-electric resonator

Informative references
Attention is drawn to the following places, which may be of interest for search:
Selection of piezo-electric material
[N: the resonator having more than two terminals (H03B 5/326 takes precedence)]
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element being a piezo-electric resonator having more than two terminals.

References relevant to classification in this subgroup
This subclass/group does not cover:
Resonators being an acoustic wave device
active element in amplifier being vacuum tube (H03B 5/38 takes precedence)
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element being a piezo-electric resonator and active element in amplifier being vacuum tube.

References relevant to classification in this subgroup
This subclass/group does not cover:
Frequency-determining elements being connected via bridge circuit to closed ring around which signal is transmitted
active element in amplifier being semiconductor device ([N: H03B 5/323H03B 5/326], H03B 5/38 take precedence)
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element being a piezo-electric resonator and active element in amplifier being semiconductor device.

References relevant to classification in this subgroup
This subclass/group does not cover:
Resonators having more than two terminals
Resonators being an acoustic wave device
Frequency-determining elements being connected via bridge circuit to closed ring around which signal is transmitted
[N: the amplifier being a single transistor (H03B 5/364 to H03B 5/368 take precedence)]
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element being a piezo-electric resonator and active element in amplifier being a single transistor.

Example:

US2008174377, T. Makuta et al.,

Oscillator including an electromechanical resonator (2) and a single transistor amplifier (Tr).

References relevant to classification in this subgroup
This subclass/group does not cover:
Amplifiers comprising field effect transistors
Means for varying the frequency by a variable voltage or current
Voltage variable capacitance diodes for varying the frequency
[N: the amplifier comprising field effect transistors (H03B 5/366 takes precedence)]
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element being a piezo-electric resonator and active element in amplifier comprising field effect transistors.

Example:

EP2341611, S. Ramet

Oscillator including an electromechanical resonator (10) and an amplifier comprising a field effect transistor (MN).

References relevant to classification in this subgroup
This subclass/group does not cover:
Means for varying the frequency by a variable voltage or current
[N: the means being voltage variable capacitance diodes]
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element being a piezo-electric resonator and active element in amplifier being semiconductor device and comprising voltage variable capacitance diodes for varying the frequency.

Example:

EP2243215; J.-B. David et al

Oscillator including an electromechanical resonator (101) and voltage variable diodes (108, 110) to vary the frequency.

being a magnetostrictive resonator (H03B 5/42 takes precedence; selection of magneto-strictive material [N: H01F 1/00]; H01L 41/00 )
Definition statement
This subclass/group covers:

Oscillators using amplifier with regenerative feedback with frequency-determining element being a magnetostrictive resonator.

References relevant to classification in this subgroup
This subclass/group does not cover:
Frequency-determining elements connected via bridge circuit to closed ring around which signal is transmitted
Informative references
Attention is drawn to the following places, which may be of interest for search:
Magnetic materials in general
Magnetostrictive elements in general
Generation of oscillations using active element having a negative resistance between two of its electrodes (H03B 9/00 takes precedence)
Definition statement
This subclass/group covers:

This main group covers:

Oscillators comprising a device with negative differential resistance as active element

- Lumped LC tanks as frequency determining element

- Distributed L and C as frequency determining element

References relevant to classification in this main group
This subclass/group does not cover:
Oscillators with regenerative feedback including gain elements such as amplifiers or transistors
Generation of oscillations using transit-time effects
Gunn diodes, in so far as their transit-time effect is relevant
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this main group, the following terms (or expressions) are used with the meaning indicated:

Negative resistance, negative conductance
A property of an electrical component or circuit characterised in that the relationship between voltage and current in the component exhibits a negative differential resistance at some point in the operating characteristic of the component. NOT: gain element like amplifier or transistor
Synonyms and Keywords

In patent documents the following abbreviations are often used:

Gunn diode
Diode, typically built as monopolar homojunction exhibiting negative differential resistance
RTD
Resonant tunnelling diode, typically built by a heterojunction multilayer structure with negative differential resistance
YIG
Yttrium iron garnet, resonating at microwave frequencies when immersed in a DC magnetic field
active element being semiconductor device
Definition statement
This subclass/group covers:

Oscillators using active element having a negative resistance between two of its electrodes with frequency-determining element comprising lumped inductance and capacitance and active element being semiconductor device.

Oscillators with negative differential resistance elements such as Gunn diodes in so far as their transit time effect is not relevant.

being a tunnel diode
Definition statement
This subclass/group covers:

Oscillators using active element having a negative resistance between two of its electrodes with frequency-determining element comprising lumped inductance and capacitance and active element being a tunnel diode.

Example:

Xiong et al., Sensors and actuators A, 150 (2009), p. 169

Oscillator using a resonant tunnel diode (RTD) as an element with negative differential resistance

active element being semiconductor device
Definition statement
This subclass/group covers:

Oscillators using active element having a negative resistance between two of its electrodes with frequency-determining element comprising distributed inductance and capacitance and active element being a semiconductor device.

Example:

US5223802, J.F. Harvey

Oscillator with frequency determining element comprising transmission as distributed inductance and a resonant tunnel diode (22) as an active semiconductor device with negative differential resistance.

Generation of oscillations using transit-time effects
Definition statement
This subclass/group covers:

This main group covers:

Oscillators comprising a device with transit-time effects as frequency determining element:

- discharge tubes

- solid state devices, e.g. Gunn-effect devices

Informative references
Attention is drawn to the following places, which may be of interest for search:
Construction of tube and circuit arrangements not adapted to a particular application
Semiconductor devices per se
Special rules of classification within this group

Gunn diodes, in so far as only their negative differential resistance is relevant, not their transit time effect, are classified in H03B 7/06.

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this main group, the following terms (or expressions) are used with the meaning indicated:

Transit-time effect
oscillation period equal to transit time
Synonyms and Keywords

In patent documents the following abbreviations are often used:

Impatt diode
IMPact ionization Avalanche Transit-Time
Schottky diode
Diode formed by a metal-semiconductor junction
Gunn diode
Diode, typically built as monopolar homojunction exhibiting negative differential resistance
using a retarding-field tube (using klystrons H03B 9/04 )
References relevant to classification in this subgroup
This subclass/group does not cover:
Using klystrons
using solid state devices, e.g. Gunn-effect devices
Definition statement
This subclass/group covers:

Examples:

US2010085126, Y.-W. Lee et al.

Oscillator with metal-insulator device (700)

US2002011604, M. Yagura et al.

Gunn-diode (601) based oscillator

[N: the frequency being determined by a cavity resonator, e.g. a hollow waveguide cavity or a coaxial cavity (H03B 9/141 to H03B 9/143H03B 9/147H03B 9/148 take precedence)]
Definition statement
This subclass/group covers:

Generation of oscillations using transit-time effects in solid state devices and elements comprising distributed inductance and capacitance, the frequency being determined by a cavity resonator

References relevant to classification in this subgroup
This subclass/group does not cover:
Voltage sensitive elements
Magnetic field sensitive elements
More than one solid state device
Frequency being determined by a stripline resonator
Frequency being determined by a dielectric resonator
[N: the frequency being determined by a stripline resonator (H03B 9/141 to H03B 9/143H03B 9/148 take precedence)]
References relevant to classification in this subgroup
This subclass/group does not cover:
Voltage sensitive elements
Magnetic field sensitive elements
More than one solid state device
Frequency being determined by a dielectric resonator
[N: the frequency being determined by a dielectric resonator (H03B 9/141 to H03B 9/143 take precedence)]
References relevant to classification in this subgroup
This subclass/group does not cover:
Voltage sensitive elements
Magnetic field sensitive elements
More than one solid state device
Generation of oscillations using a shock-excited tuned circuit (with feedback H03B 5/00)
Definition statement
This subclass/group covers:

This main group covers:

Spark excited oscillation circuits

Interrupter excited oscillation circuits

References relevant to classification in this main group
This subclass/group does not cover:
Oscillators using a shock-excited tuned circuit with feedback
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:
Shock-excited tuned circuit
Circuits where an electrical impulse is applied (repeatedly) to a resonant circuit which then oscillates freely at its resonant frequency. Not systems where oscillation is sustained by feedback.
excited by spark (spark gaps therefor H01T 9/00 )
Definition statement
This subclass/group covers:

EP1873903

Microwave generator including a spark gap (36) between central (12) and external (14) electrode.

References relevant to classification in this subgroup
This subclass/group does not cover:
Spark gaps specially adapted for generating oscillations
Generation of oscillations using deflection of electron beam in a cathode-ray tube
Definition statement
This subclass/group covers:

This main group covers:

Oscillators based on cathode ray tubes with a feedback path.

Example:

GB 126019, J. Bethenod. Electric field applied between two plates 4 to steer the electron beam and oscillate it between the two anodes 5 and 5’.

Generation of oscillations using galvano-magnetic devices, e.g. Hall-effect devices, or using super-conductivity effects (galvano-magnetic devices per se H01L 43/00 )
Definition statement
This subclass/group covers:

This main group covers:

Oscillators based on galvano-magnetic devices

- Hall effect devices

- Superconductivity effects

- Spin transfer effects or giant magnetoresistance (GMR)

Examples:

US3751691, R. Ellis

H03B15/01: Oscillator using Hall effect devices.

US2007259209, A. Slavin

H03B15/02: Oscillator using spin-polarizing effect based on giant magneto resistance

References relevant to classification in this main group
This subclass/group does not cover:
Measuring magnetic variables
Magnetic memory devices
Thin magnetic films without application as an oscillator
Informative references
Attention is drawn to the following places, which may be of interest for search:
Recording by magnetisation
Spin-exchange-coupled multilayers
Galvano-magnetic devices per se
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this main group, the following terms (or expressions) are used with the meaning indicated:

Spin torque
Torque of electron spin interacting with permanent magnetic field
Spin-transfer torque oscillator
Partially magnetized multilayer structure generating current oscillations when a DC voltage is applied
Spin valve
Partially magnetized multilayer structure leading to precession of electron spin of a traversing current
Josephson Junction
Two superconductors linked by a non-conducting barrier
Synonyms and Keywords

In patent documents the following abbreviations are often used:

GMR
Giant magneto-resistance
TMR
Tunnel magneto-resistance
SMT
Spin momentum transfer
SV
Spin valve
Generation of oscillations using radiation source and detector, e.g. with interposed variable obturator
Definition statement
This subclass/group covers:

This main group covers:

Oscillators including a radiation source and detector, for example opto-electronic oscillators based on detection of optical signals. The radiation could be in the form of light, but also other radiation types, (e.g. terahertz radiation).

Example:

WO2007143627

Opto-electronic oscillator generating electronic oscillations by detecting an optical signal

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this main group, the following terms (or expressions) are used with the meaning indicated:

Obturator
This term is not used in any of the documents in this group and is apparently not significant.
Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source (transference of modulation from one carrier to another H03D 7/00 )
Definition statement
This subclass/group covers:

This main group covers:

Generation of periodic sinusoidal waveforms based on an oscillating input signals and subsequent division or multiplication

- using non-linear inductance

- using non-linear capacitance, e.g. varactor diodes

- using discharge or semiconductor devices with more than two electrodes

- using uncontrolled rectifying devices such as diodes

Examples:

US2011143689

Generation of a periodic signal (y2) based on a higher frequency signal (y1) followed by configurable division (210) and a configurable delay (220).

Informative references
Attention is drawn to the following places, which may be of interest for search:
Generating clock signals
Transference of modulation from one carrier to another
Frequency dividers comprising counting chains
Generation of oscillations by combining unmodulated signals of different frequencies (H03B 19/00 takes precedence; frequency changing circuits in general H03D)
Definition statement
This subclass/group covers:

This main group covers:

Combination of periodic unmodulated signals of different frequencies to form an oscillating signal

- by adding or subtracting unmodulated signals of different frequencies

- by selecting unmodulated signals of different frequencies

- by beating unmodulated signals of different frequencies

Example for H03B 21/00:

US6081696

Generation of a multi-channel oscillation by adding independent signals of various frequencies.

References relevant to classification in this main group
This subclass/group does not cover:
Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source
Informative references
Attention is drawn to the following places, which may be of interest for search:
Modulation
Frequency changing circuits in general
Synonyms and Keywords
Beating
Mixing

Synonyms and Keywords

Beating
Mixing
by beating unmodulated signals of different frequencies
Definition statement
This subclass/group covers:

Example:

US7772932

Generation of an oscillation by mixing unmodulated signals of different frequencies ((4/3) RF and (1/3) RF)

by plural beating, i.e. for frequency synthesis; [N: Beating in combination with multiplication or division of frequency (digital frequency synthesis using a ROM G06F 1/02; digital frequency synthesis in general H03K; indirect frequency synthesis using a PLL H03L 7/16 )]
Informative references
Attention is drawn to the following places, which may be of interest for search:
Digital frequency synthesis using a ROM
Digital frequency synthesis in general
Indirect frequency synthesis using a PLL
Generation of oscillations periodically swept over a predetermined frequency range (angle-modulating circuits in general H03C 3/00 )
Definition statement
This subclass/group covers:

This main group covers:

Periodic sweeping of oscillation frequency

Examples:

EP2127066

Sweep of oscillation frequency of a radar generator (free running dielectric resonator oscillator, FRDRO) controlled by a complex programmable logic device (CPLD) and a direct digital synthesiser (DDS).

Informative references
Attention is drawn to the following places, which may be of interest for search:
Noise generation
Angle-modulating circuits in general
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this main group, the following terms (or expressions) are used with the meaning indicated:

EMI
Electromagnetic interference
Spread spectrum generation
Deliberate spreading of a spectrum in the frequency domain
Bandwidth
Measure of the width of a range of frequencies occupied by an oscillating signal
Synonyms and Keywords

In patent documents the following abbreviation are often used:

Frequency wobbling
Frequency sweeping
Simultaneous generation by a free-running oscillator of oscillations having different frequencies
Definition statement
This subclass/group covers:

This main group covers:

Circuits and methods generating at least two oscillating signals differing in frequency.

Examples:

GB2340681

Generation of three signals differing in frequency at individual outputs (A’, A’’, C)

US2008169846

Comb generator providing base frequency and harmonics

Informative references
Attention is drawn to the following places, which may be of interest for search:
Generation of oscillations providing a plurality of outputs of the same frequency but differing in phase
Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this main group, the following terms (or expressions) are used with the meaning indicated:

Free-running oscillator
Oscillator with no tuning of frequency for a given set of tuning parameters.
Generation of oscillations providing a plurality of outputs of the same frequency but differing in phase, other than merely two anti-phase outputs
Definition statement
This subclass/group covers:

This main group covers:

Oscillators generating polyphase signals, such as quadrature oscillators.

Examples:

US2011148535

Oscillator generating 6 signals of same frequency and 60° phase difference.

EP1764911

Quadrature oscillator

Glossary of terms
In this subclass/group, the following terms (or expressions) are used with the meaning indicated:

In this main group, the following terms (or expressions) are used with the meaning indicated:

Quadrature oscillators
Oscillators generating two signals with same frequency shifted by 90°
Generation of oscillations by methods not covered by groups H03B 5/00 to H03B 27/00, including modification of the waveform to produce sinusoidal oscillations (analogue function generators for performing computing operations G06G 7/26; use of transformers for conversion of waveform in ac-ac converters H02M 5/18 )
Definition statement
This subclass/group covers:

This main group covers:

Any types of oscillators which fall within the group definition for H03B, but which do not fall within any of the main groups. Includes combining or filtering non-sinusoidal waves to generate a sinusoid.

Examples:

EP2206231

Summing of square waves to provide an approximation of a sinusoidal waveform

References relevant to classification in this main group
This subclass/group does not cover:
Analogue function generators for performing computing operations
Generation of oscillations using a shock-excited tuned circuit
Generation of oscillations using deflection of electron beam in a cathode-ray tube
Generation of oscillations using galvano-magnetic devices, e.g. Hall-effect devices, or using super-conductivity effects
Generation of oscillations using radiation source and detector
Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source
Generation of oscillations by combining unmodulated signals of different frequencies
Generation of oscillations periodically swept over a predetermined frequency range
Simultaneous generation by a free-running oscillator of oscillations having different frequencies
Generation of oscillations providing a plurality of outputs of the same frequency but differing in phase, other than merely two anti-phase outputs
Generation of oscillations using amplifier with regenerative feedback from output to input
Generation of oscillations using active element having a negative resistance between two of its electrodes
Generation of oscillations using transit-time effects
Informative references
Attention is drawn to the following places, which may be of interest for search:
Digital function generators
Use of transformers for conversion of waveform in ac-ac converters
Generation of noise currents and voltages [N: (gasfilled discharge tubes with solid cathode specially adapted as noise generators H01J 17/005 )]
Definition statement
This subclass/group covers:

This main group covers:

Circuits used to generate random or noise signals e.g. Additive White Gaussian Noise (AWGN) or other noise distributions.

References relevant to classification in this main group
This subclass/group does not cover:
Noise cancellation systems or generation of so-called noise signals for such systems, where the generated signal is a representation of the measured noise, not a random signal.
Gasfilled discharge tubes with solid cathode specially adapted as noise generators
Details of oscillators applicable to all groups in this group
Definition statement
This subclass/group covers:

This main group covers:

Types of oscillators

Structural aspects of oscillators

Circuit elements of oscillators

Functional aspects of oscillators

References relevant to classification in this group
This subclass/group does not cover:
Oscillators with frequency-determining element comprising lumped inductance and capacitance using amplifier with regenerative feedback the active element of which comprising a semiconductor device and a voltage variable capacitance diode to vary the frequency
H03B5/12C1
Oscillators with frequency-determining element being an piezo-electric resonator using amplifier with regenerative feedback the active element of which comprising a semiconductor device and a voltage variable capacitance diode to vary the frequency
Measures to ensure starting of oscillations
References relevant to classification in this group
This subclass/group does not cover:
Oscillators using amplifier with regenerative feedback including modifications to ensure starting of oscillations
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Last Modified: 10/11/2013