|  | H |
SECTION H — ELECTRICITY

|  | H03 |
BASIC ELECTRONIC CIRCUITRY

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

|  | H03C |
Note(s) This sub-class deals only with modulation, keying, or interruption of sinusoidal oscillations or electromagnetic waves, the modulating signal having any desired waveform. 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 (Fulltext... Hierarchy... Expanded...H03C 5/00, Fulltext... Hierarchy... Expanded...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 (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...H03C 1/28-H03C 1/34, Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...H03C 1/46-H03C 1/52, Fulltext... Hierarchy... Expanded...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 (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...H03C 1/28-H03C 1/34, Fulltext... Hierarchy... Expanded...H03C 1/50, Fulltext... Hierarchy... Expanded...H03C 1/52, Fulltext... Hierarchy... Expanded...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 (Fulltext... Hierarchy... Expanded...H03C 1/34, Fulltext... Hierarchy... Expanded...H03C 1/50, Fulltext... Hierarchy... Expanded...H03C 1/52, Fulltext... Hierarchy... Expanded...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 (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...H03C 1/28-H03C 1/34, Fulltext... Hierarchy... Expanded...H03C 1/46, Fulltext... Hierarchy... Expanded...H03C 1/48 take precedence)

|  | H03C 1/52 |
· | Modulators in which carrier or one sideband is wholly or partially suppressed (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...H03C 1/28-H03C 1/34, Fulltext... Hierarchy... Expanded...H03C 1/46, Fulltext... Hierarchy... Expanded...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 (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...H03C 1/28-H03C 1/34, Fulltext... Hierarchy... Expanded...H03C 1/46, Fulltext... Hierarchy... Expanded...H03C 1/48 take precedence)

|  | H03C 3/00 |
Angle modulation (Fulltext... Hierarchy... Expanded...H03C 5/00, Fulltext... Hierarchy... Expanded...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 (Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...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 (Fulltext... Hierarchy... Expanded...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 Fulltext... Hierarchy... Expanded...G02F 1/00; for generating oscillations Fulltext... Hierarchy... Expanded...H03B, Fulltext... Hierarchy... Expanded...H03K)

|  | H03C 7/02 |
· | in transmission line, waveguide, cavity resonator, or radiation field of aerial

|  | H03C 7/04 |
· · | Polarisation of transmitted wave being modulated