Transceiver/receiver information multiplexing system

• US 4,317,222 A
• Filed: 12/31/1979
• Issued: 02/23/1982
• Est. Priority Date: 12/31/1979
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Christians, Scott T., Bell, Robert R.
• Primary Examiner(s): Ng, Jin F.
• Application Number:
  US06/108,433
• Time in Patent Office: 785 Days
• Field of Search: 455/73, 455/77, 455/78, 455/88, 455/151, 455/352-355
• US Class Current: 455/77
• CPC Class Codes: H04B 1/401 for selecting or indicating operating mode

Abstract

A radio transceiver is disclosed having manual controls on a microphone and the remainder of the circuitry located in a main chassis. The microphone and chassis are connected by means of a multiconductor cable, and time sharing multiplexing techniques are utilized and serially transmit information, bidirectionally, along a common data line while a clock line is utilized to synchronize the operation of main chassis and microphone circuitry. Multiple bit binary coded digital words are sent to the microphone to activate microphone displays while analog signals are sent from the microphone to the main chassis to provide analog control signals for the transceiver.

A digital synchronizing pulse detector is disclosed for use in the above transceiver multiplexing system. The detector identifies synchronizing pulses which occur in the clock signal wherein the identification insures the synchronization of microphone and main chassis circuitry.

The transceiver provides for designating a subset of all of the available communication channels as desired channels, and in a memory mode the transceiver is tuned only to those desired channels. Distinctive visual displays are produced indicating if any channels have been designated as desired channels, and if all possible storage space for storing desired channel identification has been utilized. In addition, the dual use of a few pushbuttons is disclosed such that the sequence in which these pushbuttons are actuated determines the transceiver mode of operation selected.

Claims

1. A transceiver/receiver information multiplexing system comprising:

transceiver/receiver means having a main chassis and a remotely located control unit coupled to the main chassis by a multiwire cable;

manually adjustable control means located on said remote control unit for adjusting the amplitude of an analog control signal for said transceiver/receiver to more than three possible amplitudes;

digital means for producing a multiple bit digital code representative of a quantity other than the amplitude of said analog control signal;

multiplexing means, including multiplexer switching circuits in each of said remote control unit and said main chassis, for periodically selectively coupling said manual control means and said digital means to said cable for serially and sequentially periodically transmitting said digital code and said analog signal amplitude on a single data conductor between said multiplexer switching circuits in said remote control unit and said main chassis; and

circuitry means located in said main chassis and coupled to said cable for periodically receiving said multiplexed analog control signal amplitude and in response thereto maintaining a fixed signal amplitude representative of the received amplitude of said analog control signal until the next periodic reception of said analog control signal amplitude, wherein said analog amplitude receiving and maintaining circuitry means in said main chassis comprises a high input impedance driving device having a control electrode coupled to a capacitor which is coupled to one of said multiplexer switching circuits and receives signals therefrom and stores an amplitude corresponding to the amplitude of said analog control signal, said fixed signal amplitude being obtained from an output terminal of said high input impedance device, said stored amplitude remaining fixed until the next reception of said analog control signal by said main chassis, whereby providing an analog to digital encoder at said remote control unit to translate said analog control signal into a digital code similar to the transmitted multiple bit digital code is avoided and a fixed signal amplitude is available for control purposes at said main chassis between periodic receptions of the multiplexed analog control signal by said main chassis.

2. A transceiver/receiver information multiplexing system according to claim 1 wherein said multiplexing means for periodically coupling said manual control means and said digital means to the cable includes means for producing a periodic timing clock signal and coupling this signal between the remote control unit and the main chassis along a single conductor of said cable.

3. A transceiver/receiver information multiplexing system according to claim 2 wherein said periodic timing clock signal contains in each period a synchronizing pulse followed by timing pulses, each of said multiplexer switching circuits receiving at least said timing pulses and in response thereto connecting various circuits to said single data conductor in predetermined sequences, and wherein said multiplexing means for selectively coupling said manual control means and said digital means to said cable includes at least one synchronizing pulse detector means located in at least one of said remote control unit and said main chassis for detecting the occurrence of said synchronizing pulse in said timing clock signal and providing in response thereto periodic initialization and synchronization of said multiplexer switching circuits in said main chassis and said control unit for coupling said manual control means and said digital means to said cable while also insuring the synchronous periodic operation of said analog signal amplitude receiving means located in main chassis.

4. A transceiver/receiver information multiplexing system according to claim 3 wherein said synchronizing pulse of said timing clock signal has a longer pulse duration than any other pulse in said clock signal, and said pulse detector means provides an initializing pulse for at least one of said multiplexer switching circuits in response to the detection of said synchronizing pulse.

5. A transceiver/receiver information multiplexing system according to claim 4 wherein said cable conductor which couples said timing clock signal is separate from said data cable conductor.

6. A transceiver/receiver information multiplexing system according to claim 3 wherein said multiplexing means transmits analog signal information representative of the state of any one of said manually adjustable control means on said single data conductor for an effective time between said periodic synchronizing pulses and wherein said multiplexing means also transmits for an effective time between said periodic synchronizing pulses a number of digital bits in said digital code, wherein the effective time between said periodic synchronizing pulses for transmitting said analog signal information representative of the state of any one of said manually adjustable control means on said single data conductor is substantially greater than the effective time for transmitting any of said digital code bits in said digital code.

7. A transceiver/receiver multiplexing system according to claim 1 wherein between said periodic reception of signals by said capacitor from said one of said multiplexer switching circuits, and one of said multiplexer switching circuits provides an open circuit to said capacitor.

8. A transceiver/receiver information multiplexing system according to claim 7 wherein said high input impedance driving device comprises a transistor and wherein said control electrode of said high input impedance driving device corresponds to the base electrode of said transistor.

9. A transceiver/receiver information multiplexing system according to claim 8 wherein said transistor is a field effect transistor (FET).

10. A transceiver/receiver information multiplexing system according to claim 9 wherein said FET is a metal-oxide silicon (MOS) transistor.

11. A transceiver/receiver information multiplexing system comprising:

transceiver/receiver means having a main chassis and a remotely located control unit coupled to the main chassis by a multi-wire cable;

a plurality of manually adjustable control means located on said remote control unit for providing control signals for said transceiver/receiver;

multiplexing means, including multiplexer switching circuits in each of said remote control unit and said main chassis, for periodically selectively coupling said plurality of manual control means to said cable for serially and sequentially periodically transmitting signals produced by each of said manually adjustable control means on a single data conductor between said multiplexer switching circuits in each of said remote control unit and said main chassis; and

circuitry means located in said main chassis and coupled to said cable for periodically receiving said transmitted multiplexed signals on said data conductor and providing in response thereto signals representative of each of said multiplexed signals until the next periodic reception of said multiplexed signals,

wherein said multiplexing means for periodically coupling each of said manual control means to the cable includes means for producing a periodic timing clock signal and coupling this signal between the remote control unit and the main chassis along a single conductor of said cable, and

wherein said periodic timing clock signal contains in each period a synchronizing pulse followed by timing pulses, each of said multiplexer switching circuits receiving at least said timing pulses and in response thereto connecting various circuits to said single data conductor in predetermined sequences, and wherein said multiplexing means for selectively coupling said manual control means to said cable includes at least one synchronizing pulse detector means located in at least one of said remote control unit and said main chassis for detecting the occurrence of said synchronizing pulse in said timing clock signal and providing in response thereto periodic initialization and synchronization of said multiplexer switching circuits in said main chassis and said remote control unit.

12. A transceiver/receiver information multiplexing system according to claim 11 wherein said synchronizing pulse of said timing clock signal has a longer pulse duration than any other pulse in said clock signal and wherein said pulse detector means provides an initializing pulse for at least one of said multiplexer switching circuits in response to the detection of said synchronizing pulse.

13. A transceiver/receiver information multiplexing system according to any of claims 11 or 12 wherein said timing clock signal has a fixed period and wherein said system includes circuitry, including logic control circuit means, for providing one mode of transceiver/receiver operation for one of said manual controls being actuated but being actuated for less than a predetermined time duration and a different mode of operation in response to said one manual control being detected as being actuated for more than said predetermined time duration, and wherein this is accomplished by the logic control circuit means counting the number of consecutive times said one manual control is coupled to said main chassis by said multiplexer switching circuits while said one manual control is actuated.

14. A transceiver/receiver information multiplexing system according to claim 13 wherein said cable conductor which couples said timing clock signal is separate from said data cable conductor.