H
SECTION H — ELECTRICITY
 H03
BASIC ELECTRONIC CIRCUITRY
 H03C
MODULATION (measuring, testing G01R; masers, lasers H01S; modulators specially adapted for use in dc amplifiers H03F 3/38; modulating pulses H03K 7/00; pulse code modulation H03K 13/00; so-called modulators capable only of switching between predetermined states of amplitude, frequency or phase H03K 17/00, H04L; synchronous modulators specially adapted for colour television H04N 9/50)
 H03C

Note(s)

  1. This sub-class deals only with modulation, keying, or interruption of sinusoidal oscillations or electromagnetic waves, the modulating signal having any desired waveform.
  2. In this sub-class, circuits usable both as modulator and demodulator are classified in the group dealing with the type of modulator involved.
 H03C 1/00
Amplitude modulation (H03C 5/00, H03C 7/00 take precedence)
 H03C 1/02
·  Details
 H03C 1/04
·  ·  Means in, or combined with, modulating stage for reducing angle modulation
 H03C 1/06
·  ·  Modification of modulator to reduce distortion, e.g. by feedback, and clearly applicable to more than one type of modulator
 H03C 1/08
·  by means of variable impedance element (H03C 1/28-H03C 1/34, H03C 1/46-H03C 1/52, H03C 1/62 take precedence)
 H03C 1/10
·  ·  the element being a current-dependent inductor
 H03C 1/12
·  ·  the element being a voltage-dependent capacitor
 H03C 1/14
·  ·  the element being a diode
 H03C 1/16
·  by means of discharge device having at least three electrodes (H03C 1/28-H03C 1/34, H03C 1/50, H03C 1/52, H03C 1/62 take precedence)
 H03C 1/18
·  ·  carrier applied to control grid
 H03C 1/20
·  ·  ·  modulating signal applied to anode
 H03C 1/22
·  ·  ·  modulating signal applied to same grid
 H03C 1/24
·  ·  ·  modulating signal applied to different grid
 H03C 1/26
·  ·  ·  modulating signal applied to cathode
 H03C 1/28
·  by means of transit-time tube
 H03C 1/30
·  ·  by means of a magnetron
 H03C 1/32
·  by deflection of electron beam in discharge tube
 H03C 1/34
·  by means of light-sensitive element
 H03C 1/36
·  by means of semiconductor device having at least three electrodes (H03C 1/34, H03C 1/50, H03C 1/52, H03C 1/62 take precedence)
 H03C 1/38
·  ·  carrier applied to base of a transistor
 H03C 1/40
·  ·  ·  modulating signal applied to collector
 H03C 1/42
·  ·  ·  modulating signal applied to base
 H03C 1/44
·  ·  ·  modulating signal applied to emitter
 H03C 1/46
·  Modulators with mechanically- or acoustically-driven parts
 H03C 1/48
·  by means of Hall-effect devices
 H03C 1/50
·  by converting angle modulation to amplitude modulation (H03C 1/28-H03C 1/34, H03C 1/46, H03C 1/48 take precedence)
 H03C 1/52
·  Modulators in which carrier or one sideband is wholly or partially suppressed (H03C 1/28-H03C 1/34, H03C 1/46, H03C 1/48 take precedence)
 H03C 1/54
·  ·  Balanced modulators, e.g. bridge type, ring type, double balanced type
 H03C 1/56
·  ·  ·  comprising variable two-pole elements only
 H03C 1/58
·  ·  ·  ·  comprising diodes
 H03C 1/60
·  ·  with one sideband wholly or partially suppressed
 H03C 1/62
·  Modulators in which amplitude of carrier component in output is dependent upon strength of modulating signal, e.g. no carrier output when no modulating signal is present (H03C 1/28-H03C 1/34, H03C 1/46, H03C 1/48 take precedence)
 H03C 3/00
Angle modulation (H03C 5/00, H03C 7/00 take precedence)
 H03C 3/02
·  Details
 H03C 3/04
·  ·  Means in, or combined with, modulating stage for reducing amplitude modulation
 H03C 3/06
·  ·  Means for changing frequency deviation
 H03C 3/08
·  ·  Modification of modulator to linearise modulation, e.g. by feedback, and clearly applicable to more than one type of modulator
 H03C 3/10
·  by means of variable impedance (H03C 3/30-H03C 3/38 take precedence)
 H03C 3/12
·  ·  by means of a variable reactive element
 H03C 3/14
·  ·  ·  simulated by circuit comprising active element with at least three electrodes, e.g. reactance-tube circuit
 H03C 3/16
·  ·  ·  ·  in which the active element simultaneously serves as the active element of an oscillator
 H03C 3/18
·  ·  ·  the element being a current-dependent inductor
 H03C 3/20
·  ·  ·  the element being a voltage-dependent capacitor
 H03C 3/22
·  ·  ·  the element being a semiconductor diode, e.g. varicap diode
 H03C 3/24
·  ·  by means of a variable resistive element, e.g. tube
 H03C 3/26
·  ·  ·  comprising two elements controlled in push-pull by modulating signal
 H03C 3/28
·  ·  using variable impedance driven mechanically or acoustically
 H03C 3/30
·  by means of transit-time tube
 H03C 3/32
·  ·  the tube being a magnetron
 H03C 3/34
·  by deflection of electron beam in discharge tube
 H03C 3/36
·  by means of light-sensitive element
 H03C 3/38
·  by converting amplitude modulation to angle modulation
 H03C 3/40
·  ·  using two signal paths the outputs of which have a predetermined phase difference and at least one output being amplitude-modulated
 H03C 5/00
Amplitude modulation and angle modulation produced simultaneously or at will by the same modulating signal (H03C 7/00 takes precedence)
 H03C 5/02
·  by means of transit-time tube
 H03C 5/04
·  ·  the tube being a magnetron
 H03C 5/06
·  by deflection of electron beam in discharge tube
 H03C 7/00
Modulating electromagnetic waves (modulating light G02F 1/00; for generating oscillations H03B, H03K)
 H03C 7/02
·  in transmission line, waveguide, cavity resonator, or radiation field of aerial
 H03C 7/04
·  ·  Polarisation of transmitted wave being modulated