GB1218550A - Speech transmission circuits - Google Patents
Speech transmission circuitsInfo
- Publication number
- GB1218550A GB1218550A GB2318567A GB2318567A GB1218550A GB 1218550 A GB1218550 A GB 1218550A GB 2318567 A GB2318567 A GB 2318567A GB 2318567 A GB2318567 A GB 2318567A GB 1218550 A GB1218550 A GB 1218550A
- Authority
- GB
- United Kingdom
- Prior art keywords
- speech
- gates
- signal
- circuit
- vca
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M3/00—Automatic or semi-automatic exchanges
- H04M3/42—Systems providing special services or facilities to subscribers
- H04M3/56—Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—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
- H04B1/40—Circuits
- H04B1/54—Circuits using the same frequency for two directions of communication
- H04B1/58—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Multimedia (AREA)
- Interface Circuits In Exchanges (AREA)
Abstract
1,218,550. Intercommunication circuits. POST OFFICE. 23 May, 1968 [18 May, 1967], No. 23185/67. Heading H4K. In a conference circuit speech from each subscriber's line is rectified, in a respective detector DET, and added to the speech signal itself, from TS2, to produce a signal which is always of negative polarity. The most negative signal of the signals on lines L1 to L4 opens the respective one of diode gates DI1 to DI4 and closes the remaining gates. The speech frequency component of the signal is selected by filter F1 and amplified by amplifier VA while the D.C. and speech envelope components are selected, by F2, and attenuated by ATT, before being applied to the output gates DO1 to D04 where the D.C. + speech envelope component enables all the gates except that connected to the line from which the speech originates. The circuit is the same as that described with respect to Fig. 7 of Specification 1,131,947 except that the emitter follower of that embodiment is replaced by the dual channel amplifier system VCA of Fig. 3. The arrangement provides compensation for the attenuation introduced by the gating system on the speech signals while maintaining appropriate D.C. biasing to operate the gates appropriately. A circuit for the dual channel amplifier VCA is described with respect to Fig. 4 (not shown).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2318567A GB1218550A (en) | 1967-05-18 | 1967-05-18 | Speech transmission circuits |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2318567A GB1218550A (en) | 1967-05-18 | 1967-05-18 | Speech transmission circuits |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1218550A true GB1218550A (en) | 1971-01-06 |
Family
ID=10191527
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2318567A Expired GB1218550A (en) | 1967-05-18 | 1967-05-18 | Speech transmission circuits |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1218550A (en) |
-
1967
- 1967-05-18 GB GB2318567A patent/GB1218550A/en not_active Expired
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