H
SECTION H — ELECTRICITY
 H03
BASIC ELECTRONIC CIRCUITRY
 H03B
GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (measuring, testing G01R; generators adapted for electrophonic musical instruments G10H; speech synthesis G10L; masers, lasers H01S; dynamo-electric machines H02K; power inverter circuits H02M; by using pulse techniques H03K; automatic control of generators H03L; starting, synchronisation or stabilisation of generators where the type of generator is irrelevant or unspecified H03L; generation of oscillations in plasma H05H)

 H03C
MODULATION (measuring, testing G01R; masers, lasers H01S; modulators specially adapted for use in dc amplifiers H03F 3/38; modulating pulses H03K 7/00; so-called modulators capable only of switching between predetermined states of amplitude, frequency or phase H03K 17/00, H04L; coding, decoding or code conversion, in general H03M; synchronous modulators specially adapted for colour television H04N 9/65)
 H03C

Note(s)

  1. This subclass covers only modulation, keying, or interruption of sinusoidal oscillations or electromagnetic waves, the modulating signal having any desired waveform.
  2. In this subclass, circuits usable both as modulator and demodulator are classified in the 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; demodulating pulses H03K 9/00; transforming types of pulse modulation H03K 11/00; coding, decoding or code conversion, in general H03M; repeater stations H04B 7/14; demodulators adapted for ac systems of digital-information transmission H04L 27/00; synchronous demodulators adapted for colour television H04N 9/66)
 H03D

Note(s)

This subclass covers only:

  • demodulation or transference of signals modulated on a sinusoidal carrier or on electromagnetic waves;
  • comparing phase or frequency of two mutually-independent oscillations.


 H03F
AMPLIFIERS (measuring, testing G01R; optical parametric amplifiers G02F; circuit arrangements with secondary emission tubes H01J 43/30; masers, lasers H01S; control of amplification H03G; coupling arrangements independent of the nature of the amplifier, voltage dividers H03H; amplifiers capable only of dealing with pulses H03K; repeater circuits in transmission lines H04B 3/36, H04B 3/58; application of speech amplifiers in telephonic communication H04M 1/60, H04M 3/40)
 H03F

Note(s)

This subclass covers:

  • linear amplification, there being linear relationship between the amplitudes of input and output, and the output having substantially the same waveform as the input;
  • dielectric amplifiers, magnetic amplifiers, and parametric amplifiers when used as oscillators or frequency-changers;
  • constructions of active elements of dielectric amplifiers and parametric amplifiers if no provision exists elsewhere.


 H03G
CONTROL OF AMPLIFICATION (impedance networks, e.g. attenuators, H03H; control of transmission in lines H04B 3/04)
 H03G

Note(s)

  1. This subclass covers:
    • controlof gain of amplifiers or frequency-changers;
    • control of frequency range of amplifiers;
    • limiting amplitude or rate of change of amplitude.
  2. Attention is drawn to the Note following the title of subclass H03F[3]

 H03H
IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (measuring, testing G01R; impedance networks or resonators consisting of distributed impedances, e.g. of the waveguide type, H01P; control of amplification, e.g. bandwidth control of amplifiers, H03G; tuning resonant circuits, e.g. tuning coupled resonant circuits, H03J; networks for modifying the frequency characteristics of communication systems H04B)
 H03H

Note(s)

  1. This subclass covers:
    • networks comprising lumped impedance elements;
    • networks comprising distributed impedance elements together with lumped impedance elements;
    • networks comprising electromechanical or electro-acoustic devices;
    • networks simulating reactances and comprising discharge tubes or semiconductor devices;
    • constructions of electromechanical resonators.
  2. In this subclass, the following expression is used with the meaning indicated:
    • "passive elements" means resistors, capacitors, inductors, mutual inductors, or diodes. [3]
  3. In this subclass, main groups with a higher number take precedence. [3]

 H03J
TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS (indicating arrangements for measuring G01D; measuring, testing G01R; remote-control in general G05, G08; automatic control or stabilisation of generators H03L)
 H03J

Note(s)

This subclass covers also the control of tuning, including the combined control of tuning and other functions, e.g. combinations of tuning control and volume control, combinations of control of local oscillator and of supplementary resonant circuits. [3]


 H03K
PULSE TECHNIQUE (measuring pulse characteristics G01R; mechanical counters having an electrical input G06M; information storage devices in general G11; sample-and-hold arrangements in electric analogue stores G11C 27/02; construction of switches involving contact making and breaking for generation of pulses, e.g. by using a moving magnet, H01H; static conversion of electric power H02M; generation of oscillations by circuits employing active elements which operate in a non-switching manner H03B; modulating sinusoidal oscillations with pulses H03C, H04L; discriminator circuits involving pulse counting H03D; automatic control of generators H03L; starting, synchronisation, or stabilisation of generators where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
 H03K

Note(s)

  1. This subclass covers:
    • methods, circuits, devices, or apparatus using active elements operating in a discontinuous or switching manner for generating, counting, amplifying, shaping, modulating, demodulating, or otherwise manipulating signals;
    • electronic switching not involving contact-making and braking;
    • logic circuits handling electric pulses.
  2. In this subclass, the following expression is used with the meaning indicated:
    • "active element" exercises control over the conversion of input energy into an oscillation or a discontinuous flow of energy.

 H03L
AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (of dynamo-electric generators H02P)  [3]
 H03L

Note(s)

  1. This subclass covers:
    • automatic control circuits for generators of electronic oscillations or pulses; [3]
    • starting, synchronisation, or stabilisation circuits for generators where the type of generator is irrelevant or unspecified. [3]
  2. This subclass does not cover stabilisation or starting circuits specially adapted to only one specific type of generator, which are covered by subclasses H03B, H03K[3]
  3. In this subclass, the following expression is used with the meaning indicated:
    • "automatic control" covers only closed loop systems. [3]

 H03M
CODING; DECODING OR CODE CONVERSION, IN GENERAL (using fluidic means F15C 4/00; optical analogue/digital converters G02F 7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G09G, G10L, G11B, G11C, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C)