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Class Number: 330 Class Title: AMPLIFIERS Subclass Subclass Number Title 1 R WITH DIVERSE-TYPE ART DEVICE 1 A .With process control system 2 WITH AMPLIFIER CONDITION INDICATING OR TESTING MEANS 3 WITH PLURAL DIVERSE-TYPE AMPLIFYING DEVICES 4 WITH MASER-TYPE AMPLIFYING DEVICE 4.5 PARAMETRIC AMPLIFIERS 4.6 .Traveling wave type 4.7 ..Electron beam device 4.8 .Gyromagnetic type (e.g., ferrite) 4.9 .Semiconductor type (e.g., with semiconductor diode) 5 WITH SOLID ELEMENT WAVE PROPAGATING AMPLIFYING DEVICE 5.5 .Phonon type (e.g., ultrasonic wave propagating device) 6 WITH HALL EFFECT TYPE MEANS 7 WITH CAPACITIVE AMPLIFYING DEVICE 8 WITH SATURABLE REACTOR-TYPE AMPLIFYING DEVICE 9 WITH PERIODIC SWITCHING INPUT-OUTPUT (E.G., FOR DRIFT CORRECTION) 10 MODULATOR-DEMODULATOR-TYPE AMPLIFIER 11 WITH D.C. REINSERTION CIRCUIT 250 WITH SEMICONDUCTOR AMPLIFYING DEVICE (E.G., TRANSISTOR) 251 .Including Class D amplifier 252 .Including differential amplifier 253 ..Having field effect transistor 254 ..Having gain control means 255 ..Having push-pull amplifier stage 256 ..Having temperature compensation means 257 ..Having current mirror amplifier 258 ..Having common mode rejection circuit 259 ..Having D.C. feedback bias control for stabilization 260 ..Having signal feedback means 261 ..Having particular biasing arrangement 262 .Including push-pull amplifier 263 ..Having complementary symmetry 264 ...And field effect transistor 265 ...And feedback means 266 ...And temperature compensation 267 ...And particular biasing arrangement 268 ....To eliminate crossover distortion 269 ..Having field effect transistor 270 ..Having D.C. feedback bias control for stabilization 271 ..Having signal feedback means 272 ..Having temperature compensating means 273 ..Having particular biasing arrangement 274 ...To eliminate crossover distortion 275 ..Having balanced to unbalanced circuitry and vice versa 276 ..Having transformer 277 .Including field effect transistor 278 .Including gain control means 279 ..And significant control voltage developing means 280 ...With delay means 281 ...With time constant means 282 ..Having feedback means acting as variable impedancee 283 ...Having emitter degeneration 284 ..Having attenuation means in signal transmission path 285 ..Having particular biasing means 286 .Including distributed parameter-type coupling 287 ..Of diode type 288 .Including current mirror amplifier 289 .Including temperature compensation means 290 .Including D.C. feedback bias control for stabilization 291 .Including signal feedback means 292 ..Having compensation for interelectrode impedance 293 ..Having negative feedback 294 ..Having frequency-responsive means or phase-shift means in feedback path 295 .Including plural amplifier channels 296 .Including particular biasing arrangement 297 .Including particular power supply circuitry 298 .Including protection means 299 .Including combined diverse-type semiconductor device 300 ..Bipolar or unipolar (FET) 301 .Including balanced to unbalanced circuits and vice versa 302 .Including frequency-responsive means in the signal transmission path 303 ..Including an active device in the filter means 304 ..And equalizing means 305 ..And tuning means 306 ..And bandpass, broadband (e.g., wideband) or sidepass means 307 .Integrated circuits 308 .Including atomic particle or radiant energy impinging on a semiconductor 309 .Involving structure of three diverse function electrode type 310 .Including plural stages cascaded 311 ..Having different configurations 41 WITH GAS OR VAPOR TUBE AMPLIFYING DEVICE 42 WITH SECONDARY ELECTRON EMISSION TUBE AMPLIFYING DEVICE 43 WITH TRAVELING WAVE-TYPE TUBE 44 WITH ELECTRON BEAM TUBE AMPLIFYING DEVICE 45 .Having electrode coupled to cavity resonator 46 .Having deflecting means 47 WITH MAGNETICALLY INFLUENCED DISCHARGE DEVICE (E.G., MAGNETRONS) 48 .Having signal applied to magnetic means 49 WITH VACUUM TUBE HAVING DISTRIBUTED PARAMETER IMPEDANCE CHARACTERISTICS 50 WITH DUMMY TUBE 51 COMBINED WITH AUTOMATIC AMPLIFIER DISABLING SWITCH MEANS 52 WITH PILOT FREQUENCY CONTROL MEANS 53 WITH DISTRIBUTED PARAMETER-TYPE COUPLING MEANS 54 .Distributed amplifier 55 .Push-pull 56 .Waveguide, cavity, or concentric line resonator 57 .Artificial line 58 WITH ROTATING DYNAMOELECTRIC AMPLIFYING DEVICE 59 HAVING LIGHT-CONTROLLED OR ACTIVATED DEVICE (I.E., NOT LIGHT SIGNAL) 60 HAVING MAGNETOSTRICTIVE-TYPE AMPLIFYING DEVICE 61 R WITH RESISTIVE-TYPE AMPLIFYING DEVICE 62 .Magnetoresistive type 61 A .Negative resistance amplifierss 63 WITH MAGNETIC MEANS AMPLIFYING DEVICE 64 WITH SPACE CHARGE GRID TUBE 65 INVOLVING STRUCTURE OTHER THAN THAT OF TRANSFORMERS PER SE 66 .With printed circuits 67 .With capacitive structure 68 .With shielding means 69 SUM AND DIFFERENCE AMPLIFIERS 70 ANODE ENERGIZED THROUGH DISCHARGE PATH OF CONTROLLED VACUUM TUBE 71 .Plural discharge paths traversed by anode supply 72 ..Amplifier devices in arms of a bridge 73 .Plural outputs 74 .Separate signal inputs to series devices 75 SIGNAL FEEDBACK 76 .Compensating for inter-electrode impedance (e.g., neutralization) 77 ..At least one push-pull stage 78 ..To or from electrode common to input and output 79 ..By transformer feedback 80 ..By coil in parallel to and resonating with inter-electrode capacity 81 .At least one push-pull signal stage 82 ..Positive and negative feedback 83 ..Including D.C. path for signal feedback 84 .Plural amplifier channels 85 .Amplifier in signal feedback path 86 .Variable impedance in feedback path varied by separate control path 87 .Cathode impedance feedback 88 ..Cascade amplifier stages with cathode-cathode feedback 89 ...Between adjacent stages 90 ..Combined with diverse-type feedback coupling 91 ...Diverse feedback to or from cathode 92 ....Feedback to cathode impedance of a prior stage 93 ...Including positive feedback 94 ..Frequency responsive means in cathode impedance feedback path 95 ..Nonlinear impedance means in cathode impedance feedback path 96 .Combined with control of bias voltage of signal amplifier 97 .Including D.C. path for signal feedback 98 .In cascade amplifiers 99 ..Multiple feedback 100 ...A feedback to input of a prior stage 101 .Positive and negative feedback in same path at different frequencies 102 .Current and voltage feedback 103 .Multiple feedback paths 104 ..Positive and negative feedback 105 .From impedance in series with output load (e.g., current feedback) 106 .In series with input source 107 .Phase shift means in loop path 108 .Potentiometer common to signal and feedback path 109 .Frequency responsive feedback means 110 .Nonlinear impedance element in loop path 111 .To or from an auxiliary grid or to the anode 112 .Positive feedback 113 POLYPHASE POWER SUPPLY (I.E., FOR AN ELECTRODE, CATHODE HEATER, OR FILAMENT)) 114 UNRECTIFIED A.C. POWER SUPPLY FOR AN ELECTRODE (I.E., NOT THE HEATER) 115 .Applied to filamentary cathode 116 WITH BALANCED-TO-UNBALANCED COUPLING 117 WITH UNBALANCED-TO-BALANCED COUPLING 118 INCLUDING A PUSH-PULL STAGE 119 .Coupling to or from cathode in push-pull 120 .Interstage coupling between push-pull 121 ..D.C. coupling 122 .Input and/or output coupling for push-pull 123 .Power or bias supply circuits and control thereof 124 R WITH PLURAL AMPLIFIER CHANNELS (E.G., PARALLEL AMPLIFIER CHANNELS) 125 .D.C. and A.C. amplifier channels 126 .Amplifying different frequencies in different channels 124 D .Redundant amplifier circuits 127 WITH CONTROL OF POWER SUPPLY OR BIAS VOLTAGE 128 .Control means for anode of screen grid circuit 129 .With control of input electrode or gain control electrode bias 130 ..Bias controlled by separate external control source 131 ..Control of bias on separate gain control electrode 132 ..Frequency selective means to select control signal from amplifier channel 133 ..Different bias control means for different stages of cascade amplifier 134 ..Plural different bias control voltages provided by separate means 135 ..Amplitude limiting or bias voltage 136 ..Bias control signal from input of amplifier 137 ..Oscillator supplies or controls bias 138 ..Bias controlled by biased rectifier or discharge device 139 ..Electronic tube controls bias 140 ..Rectifier in bias control circuit 141 ..Time constant circuit in bias control circuit 142 ..Cathode resistor supplies bias (e.g., self-biasing circuits) 143 THERMALLY RESPONSIVE IMPEDANCE 144 VARIABLE IMPEDANCE FOR SIGNAL CHANNEL CONTROLLED BY SEPARATE CONTROL PATH 145 .Electron tube or diode as impedance 146 WHEATSTONE BRIDGE WITH AMPLIFIER IN AT LEAST ONE ARM 147 PLURAL SIGNAL INPUTS 148 PLURAL SIGNAL OUTPUTS 149 HUM OR NOISE OR DISTORTION BUCKING INTRODUCED INTO SIGNAL CHANNEL 150 CASCADED SIMILAR AMPLIFYING DEVICE OF DIFFERENT CHARACTERISTICS 151 WITH AMPLIFIER BYPASS MEANS (E.G., FORWARD FEED) 152 CASCADED DIFFERENTLY COUPLED BETWEEN STAGES 153 .Including a cathode follower stage 154 .Transformer or resonant circuit in interstage coupling (e.g., stagger tuning) 155 UNICONTROL OF COUPLING OR THE CIRCUITS ASSOCIATED THEREWITH 156 BOOTSTRAP COUPLING 157 INTERSTAGE COUPLING 158 .Coupling to cathode 159 ..D.C. coupling 160 .Coupling to plate or auxiliary grid 161 ..D.C. coupling 162 .Output coupling from gridd 163 ..D.C. coupling 164 .With electronic tube or diode in coupling circuit 165 .Transformer coupling 166 ..With additional reactive coupling 167 ..With additional impedance connected to "P" or "S" circuits 168 ..From cathode 169 ..With means for adjusting inductive coupling 170 ..With shielding 171 ..With transformer structure 172 .Coupling from cathode 173 ..D.C. coupling 174 .With electromechanical transducer (e.g., piezoelectric crystal) 175 .With lattice or Wheatstone bridge network in coupling circuits 176 .With T, H, or Pi network in coupling circuit 177 .With coupling or blocking capacitor 178 ..With R or L in series between stages 179 ..L in anode or grid circuit 180 ..With R in anode and grid circuit (RC coupling) 181 .D.C. coupled 182 ..With series reactive element between stages 183 ..With nonlinear device 184 ..With series resistance between stages 185 INPUT NETWORKS 186 .To cathode 187 ..D.C. coupled 188 .Transformer coupled 189 ..With additional impedance connected to "P" or "S" circuits 190 ..With transformer structure 191 .D.C. coupled 192 OUTPUT NETWORKS 193 .From cathode 194 ..D.C. coupled 195 .Transformer coupled 196 ..With additional impedance connected to "P" or "S" circuit 197 ..With transformer structure 198 .D.C. coupled 199 WITH POWER OR BIAS VOLTAGE SUPPLY 200 .For plural stage amplifier 201 ..Filamentary cathodes heated by anode current or anode supply source 202 .For anode 203 ..And input electrode 204 .For input electrode 205 ..And filamentary cathode 206 .For filamentary cathode 207 R MISCELLANEOUS 207 A .Class D 207 P .Amplifier protection means