IPC 6 English version H04B !A-H04B 5/06

H04-H04B00506

SECTION H– ELECTRICITY

H 04

ELECTRIC COMMUNICATION TECHNIQUE

H 04 B

TRANSMISSION (transmission systems for measured values, control or similar signals G 08 C; coding, decoding or code conversion, in general H 03 M; broadcast communication H 04 H; multiplex systems H 04 J; secret communication H 04 K; transmission of digital information H 04 L) [4]

Note

This subclass covers the transmission of information-carrying signals, the transmission being independent of the nature of the information, and includes monitoring and testing arrangements and the suppression and limitation of noise and interference.

Details of transmission systems, not covered by a single one of groups H 04 B 3/00 to H 04 B 13/00; Details of transmission systems not characterised by the medium used for transmission (tuning resonant circuits H 03 J) [4]

Transmitters (spatial arrangements of component circuits in radio pills for living beings A 61 B 5/07)

Constructional details, e.g. casings, housings [2]

034

Portable transmitters [2]

036

Cooling arrangements (cooling transformers H 01 F 27/08; cooling discharge tubes H 01 J 7/24, H 01 J 19/74) [2]

Circuits (of television transmitters H 04 N 5/38)

Receivers (control of amplification H 03 G; television receivers H 04 N 5/44, H 04 N 5/64)

Constructional details, e.g. cabinet

Means associated with receiver for limiting or suppressing noise or interference

Neutralising, balancing, or compensation arrangements

Automatic detuning arrangements

Circuits

Input circuits, e.g. for coupling to an aerial or a transmission line (input circuits for amplifiers in general H 03 F; coupling networks between aerials or lines and receivers independent of the nature of the receiver H 03 H)

for coupling gramophone pick-up, recorder output, or microphone to receiver

for receivers in which no local oscillation is generated

the receiver comprising at least one semiconductor device having three or more electrodes

for superheterodyne receivers (multiple frequency-changing H 03 D 7/16)

the receiver comprising at least one semiconductor device having three or more electrodes

for homodyne or synchrodyne receivers (demodulator circuits H 03 D 1/22)

Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving

Circuits

Transmit/receive switching (tubes therefor H 01 J 17/64; waveguide switches H 01 P 1/10) [2]

by voice-frequency signals; by pilot signals

in circuit for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter (in radar systems G 01 S)

using different frequencies for the two directions of communication

Hybrid arrangements, i.e. for transition from single-path two-way transmission to single transmission on each of two paths, or vice versa

using the same frequency for both directions of communication (H 04 B 1/44 takes precedence)

with provision for simultaneous communication in both directions

Hybrid arrangements, i.e. for transition from single-path two-way transmission to single transmission on each of two paths, or vice versa

Responders; Transponders (relay systems H 04 B 7/14)

Supervising unattended repeaters

for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio

Volume compression or expansion arrangements

for reducing bandwidth of signals (in pictorial communication systems H 04 N); for improving efficiency of transmission (H 04 B 1/68 takes precedence)

for wholly or partially suppressing the carrier or one side band [4]

Spread spectrum techniques in general (for code multiplex systems H 04 J 13/02) [6]

707

using direct sequence modulation [6]

713

using frequency hopping [6]

Circuits or components for simulating aerials, e.g. dummy aerial (dissipative waveguide terminations H 01 P 1/26)

for increasing reliability, e.g. using redundant or spare channels or apparatus [3]

Pilot transmitters or receivers for control of transmission or for equalising [3]

Line transmission systems (combined with near-field transmission systems H 04 B 5/00; constructional features of cables H 01 B 11/00)

Details

Hybrid circuits (for transceivers H 04 B 1/52, H 04 B 1/58; hybrid junctions of the waveguide type H 01 P 5/16) [3]

Control of transmission; Equalising (control of amplification in general H 03 G)

by the transmitted signal

in negative-feedback path of line amplifier

by pilot signal

using pilot wire (H 04 B 3/12 take precedence) [3]

in negative-feedback path of line amplifier

characterised by the equalising network used

characterised by the negative-impedance network used

wherein the network comprises semiconductor devices

Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other

using a set of bandfilters [3]

using a replica of transmitted signal in the time domain, e.g. echo cancellers [3]

Improving frequency characteristic by the use of loading coils (loading coils per se H 01 F 17/08)

Reducing interference caused by currents induced in cable sheathing or armouring

Reducing interference caused by unbalance current in a normally balanced line

Reducing cross-talk, e.g. by compensating

by systematic interconnection of lengths of cable during laying; by addition of balancing components to cable during laying

Repeater circuits (H 04 B 3/58 takes precedence; amplifiers therefor H 03 F)

for signals in two different frequency ranges transmitted in opposite directions over the same transmission path

Artificial lines; Networks simulating a line of certain length

Circuits for by-passing of ringing signals

Arrangements for feeding power to a repeater along the transmission line

Monitoring; Testing

Testing attenuation

Systems for transmission between fixed stations via two-conductor transmission lines (H 04 B 3/54 takes precedence)

Systems for transmission between fixed stations via waveguides

Systems for transmission via power distribution lines (in alarm signalling systems G 08 B 25/06; remote indication of power network conditions, remote control of switching means in a power distribution network H 02 J 13/00)

Circuits for coupling, blocking, or by-passing of signals

Repeater circuits (amplifiers therefor H 03 F)

Systems for communication between relatively movable stations, e.g. for communication with lift (H 04 B 3/54 takes precedence)

Near-field transmission systems, e.g. inductive loop type

using transceiver

Calling systems, e.g. paging system

using a portable transmitter associated with a microphone

H04B 7/00 - H04B 17/02