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Class   330	AMPLIFIERS
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1R

WITH DIVERSE-TYPE ART DEVICE

1A

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 impedance

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

61R

WITH RESISTIVE-TYPE AMPLIFYING DEVICE

62

Magnetoresistive type

61A

Negative resistance amplifiers

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

124R

WITH PLURAL AMPLIFIER CHANNELS (E.G., PARALLEL AMPLIFIER CHANNELS)

125

D.C. and A.C. amplifier channels

126

Amplifying different frequencies in different channels

124D

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 grid

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

207R

MISCELLANEOUS

207A

Class D

207P

Amplifier protection means

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