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Outline
Indent Level
Color Curly Brackets (indicating CPC extensions to IPC) References Date Revised

CPC
COOPERATIVE PATENT CLASSIFICATION
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CONTROL OF AMPLIFICATION( impedance networks, e.g. attenuators, H03H; control of transmission in lines H04B 3/04 )
NOTE
-
This subclass covers:

- control of gain of amplifiers or frequency-changers,
- control of frequency range of amplifiers,
- limiting amplitude or rate of change of amplitude

Attention is drawn to the Note following the title of subclass H03F.

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Details of arrangements for controlling amplification
{
for arrangements combined with means for generating a controlling signal, or these means per se, see the other main groups of H03G
}
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H03G 1/0005
.
{
Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal
}
H03G 1/0011
. .
{
the device being at least one of the amplifying tubes of the amplifier
}
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H03G 1/0017
. .
{
the device being at least one of the amplifying solid state elements of the amplifier
}
. . .
{
in emitter-coupled or cascode amplifiers( H03GB4F takes precedence )
}
. . .
{
using FETs
}
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. .
{
using continuously variable impedance elements
}
H03G 1/0041
. . .
{
using thermistors
}
H03G 1/0047
. . .
{
using photo-electric elements
}
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H03G 1/0052
. . .
{
using diodes
}
H03G 1/0058
. . . .
{
PIN-diodes
}
H03G 1/0064
. . . .
{
Variable capacitance diodes
}
H03G 1/007
. . .
{
using FET type devices
}
H03G 1/0076
. . .
{
using galvanomagnetic elements
}
H03G 1/0082
. . .
{
using bipolar transistor-type devices
}
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. .
{
using discontinuously variable devices, e.g. switch-operated
}
H03G 1/0094
. . .
{
using switched capacitors
}
H03G 1/02
.
Remote control of amplification, tone, or bandwidth( remote control in general G05 , G08 ; combined with remote tuning or selection of resonant circuits H03J )
H03G 1/04
.
Modifications of control circuit to reduce distortion caused by control( modifications to reduce influence of variations of internal impedance of amplifying elements caused by control H03F 1/08 )
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Gain control in amplifiers or frequency changers
{
without distortion of the input signal
}
( gated amplifiers H03F 3/72 ; peculiar to television receivers H04N )
.
{
Digital control of analog signals
}
.
{
Control of digital or coded signals( H03G 3/3089 take precedence )
}
H03G 3/004
.
{
Control by varying the supply voltage
}
H03G 3/005
.
{
Control by a pilot signal( H03G 3/001 takes precedence )
}
H03G 3/007
.
{
Control dependent on the supply voltage
}
H03G 3/008
.
{
Control by switched capacitors
}
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.
Manually-operated control
{
H03G 3/001 and H03G 3/002 take precedence
}
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H03G 3/04
. .
in untuned amplifiers
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H03G 3/06
. . .
having discharge tubes
H03G 3/08
. . . .
incorporating negative feedback
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H03G 3/10
. . .
having semiconductor devices
H03G 3/12
. . . .
incorporating negative feedback
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H03G 3/14
. .
in frequency-selective amplifiers
H03G 3/16
. . .
having discharge tubes
H03G 3/18
. . .
having semiconductor devices
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.
Automatic control(
{
H03G 3/005 takes precedence
}
; combined with volume compression or expansion H03G 7/00 )
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H03G 3/22
. .
in amplifiers having discharge tubes
H03G 3/225
. . .
{
controlling or controlled by the (local) oscillators of a (super)heterodyne receiver
}
H03G 3/24
. . .
Control dependent upon ambient noise level or sound level
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H03G 3/26
. . .
Muting amplifier when no signal is present
{
or when only weak signals are present, or caused by the presence of noise, e.g. squelch systems
}
H03G 3/28
. . . .
in frequency-modulation receivers;
{
in angle-modulation receivers
}
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. .
in amplifiers having semiconductor devices
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. . .
{
in amplifiers suitable for low-frequencies, e.g. audio amplifiers( H03G 3/32 , H03G 3/34 take precedence )
}
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H03G 3/301
. . . .
{
the gain being continuously variable
}
H03G 3/3015
. . . . .
{
using diodes or transistors
}
H03G 3/3021
. . . . .
{
by varying the duty cycle
}
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H03G 3/3026
. . . .
{
the gain being discontinuously variable, e.g. controlled by switching
}
H03G 3/3031
. . . . .
{
using switched capacitors
}
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. . .
{
in high-frequency amplifiers or in frequency-changers( H03G 3/3052 , H03G 3/32 , H03G 3/34 take precedence )
}
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. . . .
{
in modulators, frequency-changers, transmitters or power amplifiers( transmission power control in bidirectional transmission systems H04W 52/04 )
}
. . . . .
{
for intermittent signals, e.g. burst signals
}
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. . .
{
in bandpass amplifiers( H.F. or I.F. )or in frequency-changers used in a (super)heterodyne receiver( H03G 3/32 , H03G 3/34 take precedence )
}
. . . .
{
using at least one diode as controlling device
}
. . . .
{
using at least one transistor as controlling device, the transistor being used as a variable impedance device
}
. . . .
{
Circuits generating control signals for both R.F. and I.F. stages
}
. . . .
{
Circuits generating control signals when no carrier is present, or in SSB, CW or pulse receivers
}
. . . .
{
Circuits generating control signals for digitally modulated signals
}
H03G 3/3084
. . .
{
in receivers or transmitters for electromagnetic waves other than radiowaves, e.g. lightwaves( H03G 3/32 , H03G 3/34 take precedence )
}
. . .
{
Control of digital or coded signals
}
H03G 3/3094
. . .
{
in parametric amplifiers( H03G 3/32 , H03G 3/34 take precedence )
}
. . .
the control being dependent upon ambient noise level or sound level
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H03G 3/34
. . .
Muting amplifier when no signal is present
{
or when only weak signals are present, or caused by the presence of noise signals, e.g. squelch systems
}
H03G 3/341
. . . .
{
Muting when no signals or only weak signals are present( H03G 3/344 , H03G 3/345 take precedence )
}
H03G 3/342
. . . .
{
Muting when some special characteristic of the signal is sensed which distinguishes it from noise, e.g. using speech detector( H03G 3/344 , H03G 3/345 take precedence )
}
H03G 3/344
. . . .
{
Muting responsive to the amount of noise( noise squelch )( H03G 3/345 takes precedence )
}
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H03G 3/345
. . . .
{
Muting during a short period of time when noise pulses are detected, i.e. blanking( H03G 3/348 takes precedence )
}
H03G 3/347
. . . . .
{
dependent on the rate of noise pulses
}
H03G 3/348
. . . .
{
Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits
}
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Tone control or bandwidth control in amplifiers
.
{
of digital signals( see provisionally also H03G 5/00 )
}
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.
Manually-operated control( variable bandpass or bandstop filters H03H 7/12 )
H03G 5/025
. .
{
Equalizers; Volume or gain control in limited frequency bands
}
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H03G 5/04
. .
in untuned amplifiers
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H03G 5/06
. . .
having discharge tubes
H03G 5/08
. . . .
incorporating negative feedback
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H03G 5/10
. . .
having semiconductor devices
H03G 5/12
. . . .
incorporating negative feedback
H03G 5/14
. .
in frequency-selective amplifiers
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.
Automatic control
. .
{
Equalizers; Volume or gain control in limited frequency bands
}
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H03G 5/18
. .
in untuned amplifiers
H03G 5/20
. . .
having discharge tubes
H03G 5/22
. . .
having semiconductor devices
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H03G 5/24
. .
in frequency-selective amplifiers
H03G 5/26
. . .
having discharge tubes
H03G 5/28
. . .
having semiconductor devices
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Volume compression or expansion in amplifiers
{
frequency dependent H03G 9/00
}
.
{
without controlling loop( H03G 7/007 , H03G 7/02 , H03G 7/06 take precedence )
}
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.
{
in untuned or low-frequency amplifiers e.g. audio amplifiers( H03G 7/007 , H03G 7/001 , H03G 7/008 , H03G 7/02 , H03G 7/06 take precedence )
}
H03G 7/004
. .
{
using continuously variable impedance devices
}
H03G 7/005
. .
{
using discontinuously variable devices, e.g. switch-operated
}
.
{
of digital or coded signals( see provis. also H03G 7/00 )
}
H03G 7/008
.
{
Control by a pilot signal( H03G 7/007 , H03G 7/02 , H03G 7/06 take precedence )
}
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H03G 7/02
.
having discharge tubes
H03G 7/04
. .
incorporating negative feedback
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H03G 7/06
.
having semiconductor devices
H03G 7/08
. .
incorporating negative feedback
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Combinations of two or more types of control, e.g. gain control and tone control
.
{
of digital or coded signals
}
WARNING
-
Not complete pending reclassification; see provisionally also group H03G 9/00 )

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.
in untuned amplifiers( combined tone controls for low and high frequencies H03G 5/00 )
{
compression or expansion combined with volume control H03G 7/00
}
. .
{
frequency-dependent volume compression or expansion, e.g. multiple-band systems( H03G 9/10 , H03G 9/18 take precedence )
}
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H03G 9/04
. .
having discharge tubes
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H03G 9/06
. . .
for gain control and tone control
H03G 9/08
. . . .
incorporating negative feedback
H03G 9/10
. . .
for tone control and volume expansion or compression
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H03G 9/12
. .
having semiconductor devices
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H03G 9/14
. . .
for gain control and tone control
H03G 9/16
. . . .
incorporating negative feedback
H03G 9/18
. . .
for tone control and volume expansion or compression
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H03G 9/20
.
in frequency-selective amplifiers
H03G 9/22
. .
having discharge tubes
H03G 9/24
. .
having semiconductor devices
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H03G 9/26
.
in untuned amplifying stages as well as in frequency-selective amplifying stages( gain control in both stages H03G 3/00 ; tone control or bandwidth control H03G 5/00 )
{
compression or expansion combined with volume control H03G 7/00
}
H03G 9/28
. .
all amplifying stages having discharge tubes
H03G 9/30
. .
all amplifying stages having semiconductor devices
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Limiting amplitude ; Limiting rate of change of amplitude;
{
Clipping in general
}
.
{
without controlling loop( H03G 11/004 , H03G 11/006 , H03G 11/008 , H03G 11/02 , H03G 11/04 , H03G 11/06 , H03G 11/08 take precedence; see provisional also H03G 11/00 )
}
H03G 11/004
.
{
using discharge tubes( H03G 11/008 takes precedence )
}
H03G 11/006
.
{
in circuits having distributed constants( H03G 11/008 takes precedence )
}
.
{
of digital or coded signals( see provis. also H03G 11/00 , H03G 11/02 )
}
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.
by means of diodes(
{
H03G 11/008 ,
}
H03G 11/04 , H03G 11/06 , H03G 11/08 take precedence )
H03G 11/025
. .
{
in circuits having distributed constants
}
.
Limiting level dependent on strength of signal ; Limiting level dependent on strength of carrier on which signal is modulated
{
H03G 11/008 takes precedence
}
H03G 11/06
.
{
Limiters of angle-modulated signals
}
; such limiters combined with discriminators( H03G 11/00 takes precedence; discriminators having an inherent limiting action H03D 3/00 )
.
Limiting rate of change of amplitude
{
H03G 11/008 takes precedence
}
Subject matter not provided for in other groups of this subclass
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H03G 2201/00
Indexing scheme relating to subclass H03G
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H03G 2201/10
.
Gain control characterised by the type of controlled element
H03G 2201/103
. .
being an amplifying element
H03G 2201/106
. .
being attenuating element
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H03G 2201/20
.
Gain control characterized by the position of the detection
H03G 2201/202
. .
being in baseband
H03G 2201/204
. .
being in intermediate frequency
H03G 2201/206
. .
being in radio frequency
H03G 2201/208
. .
being in power supply of the amplifier
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H03G 2201/30
.
Gain control characterized by the type of controlled signal
H03G 2201/302
. .
being baseband signal
H03G 2201/305
. .
being intermediate frequency signal
H03G 2201/307
. .
being radio frequency signal
H03G 2201/40
.
Combined gain and bias control
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H03G 2201/50
.
Gain control characterized by the means of gain control
H03G 2201/502
. .
by switching impedance in feedback loop
H03G 2201/504
. .
by summing selected parallel amplifying paths, i.e. more amplifying/attenuating paths summed together
H03G 2201/506
. .
by selecting one parallel amplifying path
H03G 2201/508
. .
by using look-up tables
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H03G 2201/60
.
Gain control characterized by varying time constants in control loop
H03G 2201/603
. .
time constant being continuous
H03G 2201/606
. .
time constant being discrete
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H03G 2201/70
.
Gain control characterized by the gain control parameter
H03G 2201/702
. .
being frequency, e.g. frequency deviations
H03G 2201/704
. .
being number of multiplexed channels
H03G 2201/706
. .
being quality indicator, e.g. BER,C/I
H03G 2201/708
. .
being temperature
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Last Modified: 10/10/2013