H03G

CONTROL OF AMPLIFICATION impedance networks, e.g. attenuators, H03H; control of transmission in lines H04B3/04

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.

In this subclass non-limiting references (in the sense of paragraph 39 of the Guide to the IPC) may still be displayed in the scheme.

H03G1/00

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

H03G1/0005

Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal

H03G1/0011

the device being at least one of the amplifying tubes of the amplifier

H03G1/0017

the device being at least one of the amplifying solid state elements of the amplifier

H03G1/0023

in emitter-coupled or cascode amplifiers H03G1/0029 takes precedence

H03G1/0029

using FETs

H03G1/0035

using continuously variable impedance elements

H03G1/0041

using thermistors

H03G1/0047

using photo-electric elements

H03G1/0052

using diodes

H03G1/0058

PIN-diodes

H03G1/0064

Variable capacitance diodes

H03G1/007

using FET type devices

H03G1/0076

using galvanomagnetic elements

H03G1/0082

using bipolar transistor-type devices

H03G1/0088

using discontinuously variable devices, e.g. switch-operated

H03G1/0094

using switched capacitors

H03G1/02

Remote control of amplification, tone, or bandwidth remote control in general G05, G08; combined with remote tuning or selection of resonant circuits H03J

H03G1/04

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 H03F1/08

H03G3/00

Gain control in amplifiers or frequency changers

without distortion of the input signal

gated amplifiers H03F3/72; peculiar to television receivers H04N

H03G3/001

Digital control of analog signals

H03G3/002

Control of digital or coded signals H03G3/3089 take precedence

H03G3/004

Control by varying the supply voltage

H03G3/005

Control by a pilot signal H03G3/001 takes precedence

H03G3/007

Control dependent on the supply voltage

H03G3/008

Control by switched capacitors

H03G3/02

Manually-operated control

H03G3/001 and H03G3/002 take precedence

H03G3/04

in untuned amplifiers

H03G3/06

having discharge tubes

H03G3/08

incorporating negative feedback

H03G3/10

having semiconductor devices

H03G3/12

incorporating negative feedback

H03G3/14

in frequency-selective amplifiers

H03G3/16

having discharge tubes

H03G3/18

having semiconductor devices

H03G3/20

Automatic control

H03G3/005 takes precedence

; combined with volume compression or expansion H03G7/00

H03G3/22

in amplifiers having discharge tubes

H03G3/225

controlling or controlled by the (local) oscillators of a (super)heterodyne receiver

H03G3/24

Control dependent upon ambient noise level or sound level

H03G3/26

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

H03G3/28

in frequency-modulation receivers

; in angle-modulation receivers

H03G3/30

in amplifiers having semiconductor devices

H03G3/3005

in amplifiers suitable for low-frequencies, e.g. audio amplifiers H03G3/32, H03G3/34 take precedence

H03G3/301

the gain being continuously variable

H03G3/3015

using diodes or transistors

H03G3/3021

by varying the duty cycle

H03G3/3026

the gain being discontinuously variable, e.g. controlled by switching

H03G3/3031

using switched capacitors

H03G3/3036

in high-frequency amplifiers or in frequency-changers H03G3/3052, H03G3/32, H03G3/34 take precedence

H03G3/3042

in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

H03G3/3047

for intermittent signals, e.g. burst signals

H03G3/3052

in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver H03G3/32, H03G3/34 take precedence

H03G3/3057

using at least one diode as controlling device

H03G3/3063

using at least one transistor as controlling device, the transistor being used as a variable impedance device

H03G3/3068

Circuits generating control signals for both R.F. and I.F. stages

H03G3/3073

Circuits generating control signals when no carrier is present, or in SSB, CW or pulse receivers

H03G3/3078

Circuits generating control signals for digitally modulated signals

H03G3/3084

in receivers or transmitters for electromagnetic waves other than radiowaves, e.g. lightwaves H03G3/32, H03G3/34 take precedence

H03G3/3089

Control of digital or coded signals

H03G3/3094

in parametric amplifiers H03G3/32, H03G3/34 take precedence

H03G3/32

the control being dependent upon ambient noise level or sound level

H03G3/34

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

H03G3/341

Muting when no signals or only weak signals are present H03G3/344, H03G3/345 take precedence

H03G3/342

Muting when some special characteristic of the signal is sensed which distinguishes it from noise, e.g. using speech detector H03G3/344, H03G3/345 take precedence

H03G3/344

Muting responsive to the amount of noise (noise squelch) H03G3/345 takes precedence

H03G3/345

Muting during a short period of time when noise pulses are detected, i.e. blanking H03G3/348 takes precedence

H03G3/347

dependent on the rate of noise pulses

H03G3/348

Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits

H03G5/00

Tone control or bandwidth control in amplifiers

H03G5/005

of digital signals see provisionally also H03G5/00

H03G5/02

Manually-operated control variable bandpass or bandstop filters H03H7/12

H03G5/025

Equalizers; Volume or gain control in limited frequency bands

H03G5/04

in untuned amplifiers

H03G5/06

having discharge tubes

H03G5/08

incorporating negative feedback

H03G5/10

having semiconductor devices

H03G5/12

incorporating negative feedback

H03G5/14

in frequency-selective amplifiers

H03G5/16

Automatic control

H03G5/165

Equalizers; Volume or gain control in limited frequency bands

H03G5/18

in untuned amplifiers

H03G5/20

having discharge tubes

H03G5/22

having semiconductor devices

H03G5/24

in frequency-selective amplifiers

H03G5/26

having discharge tubes

H03G5/28

having semiconductor devices

H03G7/00

Volume compression or expansion in amplifiers

frequency dependent H03G9/00

H03G7/001

without controlling loop H03G7/007, H03G7/02, H03G7/06 take precedence

H03G7/002

in untuned or low-frequency amplifiers, e.g. audio amplifiers H03G7/007, H03G7/001, H03G7/008, H03G7/02, H03G7/06 take precedence

H03G7/004

using continuously variable impedance devices

H03G7/005

using discontinuously variable devices, e.g. switch-operated

H03G7/007

of digital or coded signals see provis. also H03G7/00

H03G7/008

Control by a pilot signal H03G7/007, H03G7/02, H03G7/06 take precedence

H03G7/02

having discharge tubes

H03G7/04

incorporating negative feedback

H03G7/06

having semiconductor devices

H03G7/08

incorporating negative feedback

H03G9/00

Combinations of two or more types of control, e.g. gain control and tone control

H03G9/005

of digital or coded signals

H03G9/02

in untuned amplifiers combined tone controls for low and high frequencies H03G5/00

; compression or expansion combined with volume control H03G7/00

H03G9/025

frequency-dependent volume compression or expansion, e.g. multiple-band systems H03G9/10, H03G9/18 take precedence

H03G9/04

having discharge tubes

H03G9/06

for gain control and tone control

H03G9/08

incorporating negative feedback

H03G9/10

for tone control and volume expansion or compression

H03G9/12

having semiconductor devices

H03G9/14

for gain control and tone control

H03G9/16

incorporating negative feedback

H03G9/18

for tone control and volume expansion or compression

H03G9/20

in frequency-selective amplifiers

H03G9/22

having discharge tubes

H03G9/24

having semiconductor devices

H03G9/26

in untuned amplifying stages as well as in frequency-selective amplifying stages gain control in both stages H03G3/00; tone control or bandwidth control H03G5/00

; compression or expansion combined with volume control H03G7/00

H03G9/28

all amplifying stages having discharge tubes

H03G9/30

all amplifying stages having semiconductor devices

H03G11/00

Limiting amplitude

Limiting rate of change of amplitude

; Clipping in general

H03G11/002

without controlling loop H03G11/004, H03G11/006, H03G11/008, H03G11/02, H03G11/04, H03G11/06, H03G11/08 take precedence; see provisional also H03G11/00

H03G11/004

using discharge tubes H03G11/008 takes precedence

H03G11/006

in circuits having distributed constants H03G11/008 takes precedence

H03G11/008

of digital or coded signals see provis. also H03G11/00, H03G11/02

H03G11/02

by means of diodes

H03G11/008,

H03G11/04, H03G11/06, H03G11/08 take precedence

H03G11/025

in circuits having distributed constants

H03G11/04

Limiting level dependent on strength of signal

Limiting level dependent on strength of carrier on which signal is modulated

H03G11/008 takes precedence

H03G11/06

Limiters of angle-modulated signals

such limiters combined with discriminators H03G11/00 takes precedence; discriminators having an inherent limiting action H03D3/00

H03G11/08

Limiting rate of change of amplitude

H03G11/008 takes precedence

H03G99/00

Subject matter not provided for in other groups of this subclass

H03G2201/00

Indexing scheme relating to subclass H03G

H03G2201/10

Gain control characterised by the type of controlled element

H03G2201/103

being an amplifying element

H03G2201/106

being attenuating element

H03G2201/20

Gain control characterized by the position of the detection

H03G2201/202

being in baseband

H03G2201/204

being in intermediate frequency

H03G2201/206

being in radio frequency

H03G2201/208

being in power supply of the amplifier

H03G2201/30

Gain control characterized by the type of controlled signal

H03G2201/302

being baseband signal

H03G2201/305

being intermediate frequency signal

H03G2201/307

being radio frequency signal

H03G2201/40

Combined gain and bias control

H03G2201/50

Gain control characterized by the means of gain control

H03G2201/502

by switching impedance in feedback loop

H03G2201/504

by summing selected parallel amplifying paths, i.e. more amplifying/attenuating paths summed together

H03G2201/506

by selecting one parallel amplifying path

H03G2201/508

by using look-up tables

H03G2201/60

Gain control characterized by varying time constants in control loop

H03G2201/603

time constant being continuous

H03G2201/606

time constant being discrete

H03G2201/70

Gain control characterized by the gain control parameter

H03G2201/702

being frequency, e.g. frequency deviations

H03G2201/704

being number of multiplexed channels

H03G2201/706

being quality indicator, e.g. BER,C/I

H03G2201/708

being temperature