This class covers electrical communication systems with propagation paths employing light (optical communication), infra-red, ultrasonic, sonic, or infrasonic waves. [4]
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.
1
/
00
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]
1
/
02
•
Transmitters (spatial arrangements of component circuits in radio pills for living beings A 61 B 5/07)
1
/
03
•
•
Constructional details, e.g. casings, housings [2]
Means associated with receiver for limiting or suppressing noise or interference
1
/
12
•
•
•
Neutralising, balancing, or compensation arrangements
1
/
14
•
•
•
Automatic detuning arrangements
1
/
16
•
•
Circuits
1
/
18
•
•
•
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)
1
/
20
•
•
•
for coupling gramophone pick-up, recorder output, or microphone to receiver
1
/
22
•
•
•
for receivers in which no local oscillation is generated
1
/
24
•
•
•
•
the receiver comprising at least one semiconductor device having three or more electrodes
1
/
26
•
•
•
for superheterodyne receivers (multiple frequency-changing
H 03 D 7/16)
1
/
28
•
•
•
•
the receiver comprising at least one semiconductor device having three or more electrodes
1
/
30
•
•
•
for homodyne or synchrodyne receivers (demodulator circuits H 03 D 1/22)
1
/
38
•
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
1
/
40
•
•
Circuits
1
/
44
•
•
•
Transmit/receive switching (tubes therefor
H 01 J 17/64; waveguide switches H 01 P 1/10) [2]
1
/
46
•
•
•
•
by voice-frequency signals; by pilot signals
1
/
48
•
•
•
•
in circuit for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter (in radar systems
G 01 S)
1
/
50
•
•
•
using different frequencies for the two directions of communication
1
/
52
•
•
•
•
Hybrid arrangements, i.e. for transition from single-path two-way transmission to single transmission on each of two paths, or vice versa
1
/
54
•
•
•
using the same frequency for both directions of communication (H 04 B 1/44 takes precedence)
1
/
56
•
•
•
•
with provision for simultaneous communication in both directions
1
/
58
•
•
•
•
Hybrid arrangements, i.e. for transition from single-path two-way transmission to single transmission on each of two paths, or vice versa
1
/
59
•
Responders; Transponders (relay systems H 04 B 7/14)
1
/
60
•
Supervising unattended repeaters
1
/
62
•
for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio
1
/
64
•
•
Volume compression or expansion arrangements
1
/
66
•
for reducing bandwidth of signals (in pictorial communication systems H 04 N); for improving efficiency of transmission (H 04 B 1/68 takes precedence)
1
/
68
•
for wholly or partially suppressing the carrier or one side band [4]
1
/
69
•
Spread spectrum techniques in general (for code multiplex systems H 04 J 13/02) [6]
1
/
707
•
•
using direct sequence modulation [6]
1
/
713
•
•
using frequency hopping [6]
1
/
72
•
Circuits or components for simulating aerials, e.g. dummy aerial (dissipative waveguide terminations H 01 P 1/26)
1
/
74
•
for increasing reliability, e.g. using redundant or spare channels or apparatus [3]
1
/
76
•
Pilot transmitters or receivers for control of transmission or for equalising [3]
