GB1476578A - Radio transmitter receiver which automatically switches to a ready-to-receive condition - Google Patents
Radio transmitter receiver which automatically switches to a ready-to-receive conditionInfo
- Publication number
- GB1476578A GB1476578A GB2904175A GB2904175A GB1476578A GB 1476578 A GB1476578 A GB 1476578A GB 2904175 A GB2904175 A GB 2904175A GB 2904175 A GB2904175 A GB 2904175A GB 1476578 A GB1476578 A GB 1476578A
- Authority
- GB
- United Kingdom
- Prior art keywords
- timing circuit
- output
- switches
- address
- ready
- 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
- 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
- H04B1/44—Transmit/receive switching
Abstract
1476578 Radio transmitter-receivers INTERNATIONAL STANDARD ELECTRIC CORP 10 July 1975 [10 July 1974] 29041/75 Heading H4L A radio transmitter-receiver of the kind employing delta modulation for digital speech transmission in one of a plurality of channels, the modulator producing 0/1 sequences during silent intervals with a scrambler and an unscrambler adjusted to the transmitter-receiver's own address in the ready-to-receive state and switchable to a desired address for transmission, includes a timing circuit 17 which automatically switches the set to the ready-to-receive state if for a predetermined time the set has neither transmitted, nor received 0/1 sequences from another such set. In the receive mode the output of unscrambler 4 is connected via a switch 10 to an 0/1 sequence recognition unit 11. An output signal corresponding to the presence of an 0/1 sequence passes via a connection 15 to an OR gate 16 and starts timing circuit 17 producing logic "1" which then prevents channel switching unit 19 from switching local oscillator 21 to another channel. Timing circuit 17 also has connections to an AND gate 27 and to a control circuit 29, and if a push-to-talk button 30 is depressed while 17 is still on control circuit 29 keeps 17 on via a connection 39, and the output of AND gate 27 causes the set to switch to the transmit mode. If timing circuit 17 is off when button 30 is depressed a channel idle test unit 32 searches for an idle channel, and if it locates one it restarts the timing circuit and thus stops channel switching unit 19. At the same time a call timing circuit 33 is operated which first connects an 0/1 sequence generator 35 to scrambler 5 and then switches the latter over to a delta modulator 38 and microphone 37. When timing circuit 17 turns off, logic "0" applied over a connection 46 resets address input unit 36 to the station's own address. To insert 0/1 sequences into silent intervals during the transmit mode, a first embodiment includes connections 42, 43 to switches 10, 12 respectively, so that in the transmit mode the output of delta modulator 38 passes into 0/1 sequence recognition unit 11, the output of which passes into a further timing circuit 44 having a shorter time constant than timing circuit 17. After a silent interval of predetermined length, 44 switches 0/1 sequence generator 35 into the input of scrambler 5, for a period so brief that intelligibility is unaffected. In a second embodiment (not illustrated) the output of delta modulator 38 is applied to unscrambler 4 which is permanently connected to the input of 11.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE2433163A DE2433163C2 (en) | 1974-07-10 | 1974-07-10 | Radio transceiver for digital voice transmission with delta modulation with more than one high-frequency channel |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1476578A true GB1476578A (en) | 1977-06-16 |
Family
ID=5920197
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2904175A Expired GB1476578A (en) | 1974-07-10 | 1975-07-10 | Radio transmitter receiver which automatically switches to a ready-to-receive condition |
Country Status (7)
Country | Link |
---|---|
CH (1) | CH586977A5 (en) |
DE (1) | DE2433163C2 (en) |
ES (1) | ES439288A1 (en) |
FR (1) | FR2278211A1 (en) |
GB (1) | GB1476578A (en) |
NL (1) | NL7508145A (en) |
SE (1) | SE398587B (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2083977B (en) * | 1980-08-26 | 1984-08-22 | Standard Telephones Cables Ltd | Single channel duplex radio system |
US4501017A (en) * | 1983-01-31 | 1985-02-19 | Motorola, Inc. | Switch controller for obtaining a plurality of functions from a single switch in a two-way transceiver and method therefor |
-
1974
- 1974-07-10 DE DE2433163A patent/DE2433163C2/en not_active Expired
-
1975
- 1975-07-09 CH CH895775A patent/CH586977A5/xx not_active IP Right Cessation
- 1975-07-09 SE SE7507850A patent/SE398587B/en unknown
- 1975-07-09 NL NL7508145A patent/NL7508145A/en not_active Application Discontinuation
- 1975-07-10 ES ES439288A patent/ES439288A1/en not_active Expired
- 1975-07-10 GB GB2904175A patent/GB1476578A/en not_active Expired
- 1975-07-10 FR FR7521685A patent/FR2278211A1/en active Granted
Also Published As
Publication number | Publication date |
---|---|
NL7508145A (en) | 1976-01-13 |
ES439288A1 (en) | 1977-02-16 |
SE398587B (en) | 1977-12-27 |
DE2433163C2 (en) | 1976-01-08 |
FR2278211B1 (en) | 1978-09-22 |
DE2433163B1 (en) | 1975-05-28 |
SE7507850L (en) | 1976-01-12 |
FR2278211A1 (en) | 1976-02-06 |
CH586977A5 (en) | 1977-04-15 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed [section 19, patents act 1949] | ||
732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
PCNP | Patent ceased through non-payment of renewal fee |