| Class Number |
Class Name |
No. of Patents |
| 330/70 |
Anode energized through discharge path of controlled vacuum tube |
6 |
| 330/71 |
Plural discharge paths traversed by anode supply |
4 |
| 330/72 |
Amplifier devices in arms of a bridge |
0 |
| 330/73 |
Plural outputs |
0 |
| 330/74 |
Separate signal inputs to series devices |
0 |
| 330/156 |
Bootstrap coupling |
39 |
| 330/152 |
Cascaded differently coupled between stages |
2 |
| 330/153 |
Including a cathode follower stage |
2 |
| 330/154 |
Transformer or resonant circuit in interstage coupling (e.g., stagger tuning) |
4 |
| 330/150 |
Cascaded similar amplifying device of different characteristics |
34 |
| 330/51 |
Combined with automatic amplifier disabling switch means |
772 |
| 330/59 |
Having light-controlled or activated device (i.e., not light signal) |
200 |
| 330/60 |
Having magnetostrictive-type amplifying device |
3 |
| 330/149 |
Hum or noise or distortion bucking introduced into signal channel |
1212 |
| 330/118 |
Including a push-pull stage |
23 |
| 330/119 |
Coupling to or from cathode in push-pull |
5 |
| 330/122 |
Input and/or output coupling for push-pull |
11 |
| 330/120 |
Interstage coupling between push-pull |
3 |
| 330/121 |
D.c. coupling |
2 |
| 330/123 |
Power or bias supply circuits and control thereof |
20 |
| 330/185 |
Input networks |
3 |
| 330/191 |
D.c. coupled |
2 |
| 330/186 |
To cathode |
1 |
| 330/187 |
D.c. coupled |
1 |
| 330/188 |
Transformer coupled |
18 |
| 330/189 |
With additional impedance connected to "p" or "s" circuits |
8 |
| 330/190 |
With transformer structure |
6 |
| 330/157 |
Interstage coupling |
4 |
| 330/172 |
Coupling from cathode |
1 |
| 330/173 |
D.c. coupling |
0 |
| 330/158 |
Coupling to cathode |
1 |
| 330/159 |
D.c. coupling |
1 |
| 330/160 |
Coupling to plate or auxiliary grid |
0 |
| 330/161 |
D.c. coupling |
0 |
| 330/181 |
D.c. coupled |
1 |
| 330/183 |
With nonlinear device |
0 |
| 330/182 |
With series reactive element between stages |
0 |
| 330/184 |
With series resistance between stages |
1 |
| 330/162 |
Output coupling from grid |
2 |
| 330/163 |
D.c. coupling |
1 |
| 330/165 |
Transformer coupling |
47 |
| 330/168 |
From cathode |
0 |
| 330/167 |
With additional impedance connected to "p" or "s" circuits |
8 |
| 330/166 |
With additional reactive coupling |
7 |
| 330/169 |
With means for adjusting inductive coupling |
2 |
| 330/170 |
With shielding |
1 |
| 330/171 |
With transformer structure |
9 |
| 330/177 |
With coupling or blocking capacitor |
2 |
| 330/179 |
L in anode or grid circuit |
1 |
| 330/180 |
With r in anode and grid circuit (rc coupling) |
1 |
| 330/178 |
With r or l in series between stages |
1 |
| 330/174 |
With electromechanical transducer (e.g., piezoelectric crystal) |
24 |
| 330/164 |
With electronic tube or diode in coupling circuit |
1 |
| 330/175 |
With lattice or wheatstone bridge network in coupling circuits |
1 |
| 330/176 |
With t, h, or pi network in coupling circuit |
2 |
| 330/65 |
Involving structure other than that of transformers per se |
32 |
| 330/67 |
With capacitive structure |
11 |
| 330/66 |
With printed circuits |
64 |
| 330/68 |
With shielding means |
30 |
| 330/207R |
Miscellaneous |
15 |
| 330/207P |
Amplifier protection means |
321 |
| 330/207A |
Class d |
421 |
| 330/10 |
Modulator-demodulator-type amplifier |
799 |
| 330/192 |
Output networks |
8 |
| 330/198 |
D.c. coupled |
0 |
| 330/193 |
From cathode |
2 |
| 330/194 |
D.c. coupled |
0 |
| 330/195 |
Transformer coupled |
41 |
| 330/196 |
With additional impedance connected to "p" or "s" circuit |
9 |
| 330/197 |
With transformer structure |
6 |
| 330/4.5 |
Parametric amplifiers |
35 |
| 330/4.8 |
Gyromagnetic type (e.g., ferrite) |
1 |
| 330/4.9 |
Semiconductor type (e.g., with semiconductor diode) |
31 |
| 330/4.6 |
Traveling wave type |
19 |
| 330/4.7 |
Electron beam device |
11 |
| 330/147 |
Plural signal inputs |
45 |
| 330/148 |
Plural signal outputs |
36 |
| 330/113 |
Polyphase power supply (i.e., for an electrode, cathode heater, or filament) |
1 |
| 330/75 |
Signal feedback |
40 |
| 330/85 |
Amplifier in signal feedback path |
271 |
| 330/81 |
At least one push-pull signal stage |
5 |
| 330/83 |
Including d.c. path for signal feedback |
3 |
| 330/82 |
Positive and negative feedback |
3 |
| 330/87 |
Cathode impedance feedback |
1 |
| 330/88 |
Cascade amplifier stages with cathode-cathode feedback |
5 |
| 330/89 |
Between adjacent stages |
1 |
| 330/90 |
Combined with diverse-type feedback coupling |
1 |
| 330/91 |
Diverse feedback to or from cathode |
0 |
| 330/92 |
Feedback to cathode impedance of a prior stage |
0 |
| 330/93 |
Including positive feedback |
0 |
| 330/94 |
Frequency responsive means in cathode impedance feedback path |
3 |
| 330/95 |
Nonlinear impedance means in cathode impedance feedback path |
3 |
| 330/96 |
Combined with control of bias voltage of signal amplifier |
13 |
| 330/76 |
Compensating for inter-electrode impedance (e.g., neutralization) |
10 |
| 330/77 |
At least one push-pull stage |
2 |
| 330/80 |
By coil in parallel to and resonating with inter-electrode capacity |
1 |
| 330/79 |
By transformer feedback |
12 |
| 330/78 |
To or from electrode common to input and output |
3 |
| 330/102 |
Current and voltage feedback |
29 |
| 330/109 |
Frequency responsive feedback means |
257 |
| 330/105 |
From impedance in series with output load (e.g., current feedback) |
31 |
| 330/98 |
In cascade amplifiers |
96 |
| 330/99 |
Multiple feedback |
45 |
| 330/100 |
A feedback to input of a prior stage |
59 |
| 330/106 |
In series with input source |
3 |
| 330/97 |
Including d.c. path for signal feedback |
12 |
| 330/103 |
Multiple feedback paths |
63 |
| 330/104 |
Positive and negative feedback |
33 |
| 330/110 |
Nonlinear impedance element in loop path |
182 |
| 330/107 |
Phase shift means in loop path |
409 |
| 330/84 |
Plural amplifier channels |
138 |
| 330/101 |
Positive and negative feedback in same path at different frequencies |
6 |
| 330/112 |
Positive feedback |
29 |
| 330/108 |
Potentiometer common to signal and feedback path |
31 |
| 330/111 |
To or from an auxiliary grid or to the anode |
0 |
| 330/86 |
Variable impedance in feedback path varied by separate control path |
284 |
| 330/69 |
Sum and difference amplifiers |
369 |
| 330/143 |
Thermally responsive impedance |
18 |
| 330/155 |
Unicontrol of coupling or the circuits associated therewith |
4 |
| 330/114 |
Unrectified a.c. power supply for an electrode (i.e., not the heater) |
0 |
| 330/115 |
Applied to filamentary cathode |
0 |
| 330/144 |
Variable impedance for signal channel controlled by separate control path |
117 |
| 330/145 |
Electron tube or diode as impedance |
90 |
| 330/146 |
Wheatstone bridge with amplifier in at least one arm |
122 |
| 330/151 |
With amplifier bypass means (e.g., forward feed) |
528 |
| 330/2 |
With amplifier condition indicating or testing means |
266 |
| 330/116 |
With balanced-to-unbalanced coupling |
9 |
| 330/7 |
With capacitive amplifying device |
6 |
| 330/127 |
With control of power supply or bias voltage |
140 |
| 330/128 |
Control means for anode of screen grid circuit |
13 |
| 330/129 |
With control of input electrode or gain control electrode bias |
475 |
| 330/135 |
Amplitude limiting or bias voltage |
28 |
| 330/136 |
Bias control signal from input of amplifier |
367 |
| 330/138 |
Bias controlled by biased rectifier or discharge device |
55 |
| 330/130 |
Bias controlled by separate external control source |
27 |
| 330/142 |
Cathode resistor supplies bias (e.g., self-biasing circuits) |
1 |
| 330/131 |
Control of bias on separate gain control electrode |
12 |
| 330/133 |
Different bias control means for different stages of cascade amplifier |
212 |
| 330/139 |
Electronic tube controls bias |
12 |
| 330/132 |
Frequency selective means to select control signal from amplifier channel |
33 |
| 330/137 |
Oscillator supplies or controls bias |
24 |
| 330/134 |
Plural different bias control voltages provided by separate means |
133 |
| 330/140 |
Rectifier in bias control circuit |
90 |
| 330/141 |
Time constant circuit in bias control circuit |
95 |
| 330/11 |
With d.c. reinsertion circuit |
41 |
| 330/53 |
With distributed parameter-type coupling means |
148 |
| 330/57 |
Artificial line |
3 |
| 330/54 |
Distributed amplifier |
114 |
| 330/55 |
Push-pull |
15 |
| 330/56 |
Waveguide, cavity, or concentric line resonator |
74 |
| 330/1R |
With diverse-type art device |
8 |
| 330/1A |
With process control system |
6 |
| 330/50 |
With dummy tube |
2 |
| 330/44 |
With electron beam tube amplifying device |
32 |
| 330/46 |
Having deflecting means |
6 |
| 330/45 |
Having electrode coupled to cavity resonator |
55 |
| 330/41 |
With gas or vapor tube amplifying device |
5 |
| 330/6 |
With hall effect type means |
20 |
| 330/63 |
With magnetic means amplifying device |
6 |
| 330/47 |
With magnetically influenced discharge device (e.g., magnetrons) |
12 |
| 330/48 |
Having signal applied to magnetic means |
3 |
| 330/4 |
With maser-type amplifying device |
24 |
| 330/9 |
With periodic switching input-output (e.g., for drift correction) |
695 |
| 330/52 |
With pilot frequency control means |
146 |
| 330/124R |
With plural amplifier channels (e.g., parallel amplifier channels) |
668 |
| 330/126 |
Amplifying different frequencies in different channels |
189 |
| 330/125 |
D.c. and a.c. amplifier channels |
7 |
| 330/124D |
Redundant amplifier circuits |
96 |
| 330/3 |
With plural diverse-type amplifying devices |
29 |
| 330/199 |
With power or bias voltage supply |
36 |
| 330/202 |
For anode |
25 |
| 330/203 |
And input electrode |
2 |
| 330/206 |
For filamentary cathode |
3 |
| 330/204 |
For input electrode |
2 |
| 330/205 |
And filamentary cathode |
0 |
| 330/200 |
For plural stage amplifier |
11 |
| 330/201 |
Filamentary cathodes heated by anode current or anode supply source |
0 |
| 330/61R |
With resistive-type amplifying device |
10 |
| 330/62 |
Magnetoresistive type |
6 |
| 330/61A |
Negative resistance amplifiers |
17 |
| 330/58 |
With rotating dynamoelectric amplifying device |
2 |
| 330/8 |
With saturable reactor-type amplifying device |
19 |
| 330/42 |
With secondary electron emission tube amplifying device |
12 |
| 330/250 |
With semiconductor amplifying device (e.g., transistor) |
51 |
| 330/308 |
Including atomic particle or radiant energy impinging on a semiconductor |
395 |
| 330/301 |
Including balanced to unbalanced circuits and vice versa |
173 |
| 330/251 |
Including class d amplifier |
557 |
| 330/299 |
Including combined diverse-type semiconductor device |
38 |
| 330/300 |
Bipolar or unipolar (fet) |
240 |
| 330/288 |
Including current mirror amplifier |
704 |
| 330/290 |
Including d.c. feedback bias control for stabilization |
145 |
| 330/252 |
Including differential amplifier |
696 |
| 330/258 |
Having common mode rejection circuit |
595 |
| 330/257 |
Having current mirror amplifier |
903 |
| 330/259 |
Having d.c. feedback bias control for stabilization |
280 |
| 330/253 |
Having field effect transistor |
1327 |
| 330/254 |
Having gain control means |
830 |
| 330/261 |
Having particular biasing arrangement |
788 |
| 330/255 |
Having push-pull amplifier stage |
566 |
| 330/260 |
Having signal feedback means |
677 |
| 330/256 |
Having temperature compensation means |
170 |
| 330/286 |
Including distributed parameter-type coupling |
465 |
| 330/287 |
Of diode type |
58 |
| 330/277 |
Including field effect transistor |
712 |
| 330/302 |
Including frequency-responsive means in the signal transmission path |
495 |
| 330/306 |
And bandpass, broadband (e.g., wideband) or sidepass means |
327 |
| 330/304 |
And equalizing means |
103 |
| 330/305 |
And tuning means |
197 |
| 330/303 |
Including an active device in the filter means |
118 |
| 330/278 |
Including gain control means |
387 |
| 330/279 |
And significant control voltage developing means |
530 |
| 330/280 |
With delay means |
83 |
| 330/281 |
With time constant means |
99 |
| 330/284 |
Having attenuation means in signal transmission path |
462 |
| 330/282 |
Having feedback means acting as variable impedance |
314 |
| 330/283 |
Having emitter degeneration |
103 |
| 330/285 |
Having particular biasing means |
553 |
| 330/296 |
Including particular biasing arrangement |
787 |
| 330/297 |
Including particular power supply circuitry |
564 |
| 330/295 |
Including plural amplifier channels |
808 |
| 330/310 |
Including plural stages cascaded |
382 |
| 330/311 |
Having different configurations |
580 |
| 330/298 |
Including protection means |
397 |
| 330/262 |
Including push-pull amplifier |
81 |
| 330/275 |
Having balanced to unbalanced circuitry and vice versa |
43 |
| 330/263 |
Having complementary symmetry |
171 |
| 330/265 |
And feedback means |
175 |
| 330/264 |
And field effect transistor |
269 |
| 330/267 |
And particular biasing arrangement |
342 |
| 330/268 |
To eliminate crossover distortion |
99 |
| 330/266 |
And temperature compensation |
38 |
| 330/270 |
Having d.c. feedback bias control for stabilization |
41 |
| 330/269 |
Having field effect transistor |
98 |
| 330/273 |
Having particular biasing arrangement |
100 |
| 330/274 |
To eliminate crossover distortion |
35 |
| 330/271 |
Having signal feedback means |
55 |
| 330/272 |
Having temperature compensating means |
27 |
| 330/276 |
Having transformer |
78 |
| 330/291 |
Including signal feedback means |
117 |
| 330/292 |
Having compensation for interelectrode impedance |
201 |
| 330/294 |
Having frequency-responsive means or phase-shift means in feedback path |
307 |
| 330/293 |
Having negative feedback |
186 |
| 330/289 |
Including temperature compensation means |
366 |
| 330/307 |
Integrated circuits |
388 |
| 330/309 |
Involving structure of three diverse function electrode type |
6 |
| 330/5 |
With solid element wave propagating amplifying device |
22 |
| 330/5.5 |
Phonon type (e.g., ultrasonic wave propagating device) |
22 |
| 330/64 |
With space charge grid tube |
1 |
| 330/43 |
With traveling wave-type tube |
99 |
| 330/117 |
With unbalanced-to-balanced coupling |
9 |
| 330/49 |
With vacuum tube having distributed parameter impedance characteristics |
7 |
