H
SECTION H — ELECTRICITY
 H03
BASIC ELECTRONIC CIRCUITRY
 H03B
GENERATION OF OSCILLATIONS (measuring, testing G01R; generators adapted for electrophonic musical instruments G10H; masers, lasers H01S; dynamo-electric machines H02K; power inverter circuits H02M; details applicable both to generators of sinusoidal oscillations and to generators of non-sinusoidal oscillations H03K; generation of substantially non-sinusoidal oscillations H03K; generation of sinusoidal or non-sinusoidal oscillations at will H03K; generation of oscillations in plasma H05H)
 H03B

Note(s)

This sub-class deals with (a) generation of substantially sinusoidal oscillations directly or by frequency-changing; (b) regulation of generator output; (c) synchronisation of generator output; and (d) generation of noise currents and voltages.


 H03C
MODULATION (measuring, testing G01R; masers, lasers H01S; modulators specially adapted for use in dc amplifiers H03F 3/38; 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 sub-group dealing with the type of modulator involved.

 H03D
DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER (masers, lasers H01S; circuits capable of acting both as modulator and demodulator H03C; details applicable to both modulators and frequency-changers H03C; repeater stations H04B 7/14; so-called "demodulators" capable only of discriminating between predetermined states of amplitude frequency, or phase H04L; synchronous demodulators adapted for colour television H04N 9/50)
 H03D

Note(s)

This sub-class deals only with (a) demodulation or transference of signals modulated on a sinusoidal carrier or on electromagnetic waves, and (b) comparing phase or frequency of two mutually-independent oscillations.


 H03F
AMPLIFIERS (measuring, testing G01R; masers, lasers H01S; coupling arrangements quite independent of the nature of the amplifier H03H; amplifiers capable only of dealing with pulses H03K)
 H03F

Note(s)

This sub-class deals with (a) linear amplification, there being linear relationship between the amplitudes of input and output, and the output having substantially the same waveform as the input, (b) dielectric amplifiers, magnetic amplifiers, and parametric amplifiers when used as oscillators or frequency-changers, and (c) constructions of active elements of dielectric amplifiers and parametric amplifiers for which no provision exists elsewhere.


 H03G
CONTROL OF AMPLIFICATION (control of transmission in lines H04B 3/04)
 H03G

Note(s)

This sub-class deals with (a) control of gain of amplifiers or frequency-changers: (b) control of frequency range of amplifiers and (c) limiting amplitude or rate of change of amplitude.


 H03H
IMPEDANCE NETWORKS; RESONANT CIRCUITS; RESONATORS (measuring, testing G01R; impedance networks or resonators comprising of distributed impedance elements only i.e. of the waveguide type, H01P; networks specially designed for coupling between the active elements in an amplifier, e.g. wide-band coupling networks, H03F; networks for modifying the frequency characteristics of communication cables, e.g. equalising networks, H04B 3/14)
 H03H

Note(s)

This sub-class deals with (a) networks comprising lumped impedance elements; (b) networks comprising distributed impedance elements together with lumped impedance elements; (c) networks comprising electromechanical or electro-acoustic devices; (d) networks simulating reactances and comprising discharge tubes or semiconductor devices, and (e) constructions of electromechanical resonators.


 H03J
TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS (indicating arrangements for measuring G01D; measuring, testing G01R; remote-control in general G05, G08; control of generators H03B)

 H03K
PULSE TECHNIQUE (measuring pulse characteristics G01R; mechanical counters having an electrical input G06M; storage devices G11; construction of switches involving contact making and breaking for generation of pulses, e.g. by using a moving magnet, H01H; generators of substantially sinusoidal oscillations H03B; modulating sinusoidal oscillations with pulses H03C, H04L; discriminator circuits involving pulse counting H03D)
 H03K

Note(s)

  1. This sub-class deals with (a) methods, circuits, devices, or apparatus for generating, counting, amplifying, shaping, modulating, demodulating, coding, decoding, or otherwise manipulating substantially non-sinusoidal oscillations, i.e. electric pulses, (b) electronic switching not involving contact-making and breaking, and (c) logic circuits handling electric pulses.
  2. In this sub-class: An "active element" is understood to exercise control over the conversion of input energy into an oscillation or a discontinuous flow of energy.