CONTROL OF AMPLIFICATION (impedance networks, e.g. attenuators, H 03 H; control of transmission in lines
H 04 B 3/04)
Notes
(1)
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.
(2)
Attention is drawn to the Note following the title of subclass H 03 F. [3]
1
/
00
Details of arrangements for controlling amplification
1
/
02
•
Remote control of amplification, tone, or bandwidth (remote control in general G 05, G 08; combined with remote tuning or selection of resonant circuits H 03 J)
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 H 03 F 1/08)
3
/
00
Gain control in amplifiers or frequency changers (gated amplifiers H 03 F 3/72; peculiar to television receivers
H 04 N)
3
/
02
•
Manually-operated control
3
/
04
•
•
in untuned amplifiers
3
/
06
•
•
•
having discharge tubes
3
/
08
•
•
•
•
incorporating negative feedback
3
/
10
•
•
•
having semiconductor devices
3
/
12
•
•
•
•
incorporating negative feedback
3
/
14
•
•
in frequency-selective amplifiers
3
/
16
•
•
•
having discharge tubes
3
/
18
•
•
•
having semiconductor devices
3
/
20
•
Automatic control (combined with volume compression or expansion H 03 G 7/00)
3
/
22
•
•
in amplifiers having discharge tubes
3
/
24
•
•
•
Control dependent upon ambient noise level or sound level
3
/
26
•
•
•
Muting amplifier when no signal is present
3
/
28
•
•
•
•
in frequency-modulation receivers
3
/
30
•
•
in amplifiers having semiconductor devices
3
/
32
•
•
•
the control being dependent upon ambient noise level or sound level
3
/
34
•
•
•
Muting amplifier when no signal is present
5
/
00
Tone control or bandwidth control in amplifiers
5
/
02
•
Manually-operated control (variable bandpass or bandstop filters H 03 H 7/12)
