Duplex interconnect dispatch trunked radio

• US 5,408,466 A
• Filed: 01/22/1990
• Issued: 04/18/1995
• Est. Priority Date: 12/06/1984
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Ablay, Sewim F.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Jung, Min
• Application Number:
  US07/471,020
• Time in Patent Office: 1,912 Days
• Field of Search: 370/110.1, 370/110.2, 370/110.3, 370/24, 370/38, 370/95.1, 370/31, 370/26, 370/30.32, 455/79, 455/82, 455/188.1, 455/266, 455/31, 455/33, 455/56, 455/54, 455/75, 379/56, 379/57, 379/58, 379/59, 379/60, 379/63
• US Class Current: 370/278
• CPC Class Codes: H04B 1/54 using the same frequency for two directions of communication H04B1/44 takes precedence
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A subscriber unit for use with a duplex communication system is described. The present invention contemplates a duplex transceiver which incorporates data and voice handling capability. A microprocessor generates data and DTMF signaling as well as decoding received data. According to the principles of the present invention, an improved duplex capable subscriber unit is achieved by coupling a microprocessor to a duplex transceiver through switchable filters. The filters exhibit a relatively fast or slow time constant depending on the state of a filter control input. The microprocessor is then capable of operating the subscriber unit with optimum frequency response characteristics depending on whether voice or data is being received. In addition, a summing network coupled between the microprocessor and the transmit switchable filter cooperates with the switchable filter and allows the duplex subscriber unit of the present invention to generate DTMF signaling.

Claims

1. A subscriber unit for use in a simplex/duplex communication system, comprising:

(a) duplex transceiver means having data/tone and voice transmitter inputs and demodulated data, and voice outputs;

(b) processor means for generating data and DTMF tones, decoding received data, controlling the overall operation of said subscriber unit and generating a signal indicating whether data or voice is currently being received;

(c) summing means coupled to the DTMF tone and data outputs of said processing means for combining the DTMF tones generated by said processor means;

(d) first filter means having an input responsive to said generated signal for switchably controlling the frequency response of said filter, coupled between said summing means and the data/tone transmitter input of said transceiver means;

(e) second filter means having an input responsive to said generated signal for switchably controlling the frequency response of said filter, coupled between the receiver output of said transceiver means and said processing means.

3. The subscriber unit as recited in claim 1 wherein the frequency response of said second filter means is switched in response to a received signal having a variable data rate.

4. The subscriber unit as recited in claim 1 wherein the frequency response of said first filter means is switched in response to a generated signal which indicates the data rate of a signal to be transmitted.

5. The subscriber unit as recited in claim 1 wherein said first filter means is switchable between first and second frequency responses, wherein said first frequency response is characterized by a maximally flat Bessel function, and said second frequency response is characterized as a Chebychev function.

2. A duplex interconnect capable subscriber unit for use with a dispatch trunked radio system, said subscriber unit comprising:

(a) Antenna means for receiving and transmitting an R.F. signal;

(b) Duplexer means for coupling signals to said antenna from modulator and demodulator circuits;

(c) means for modulating voice and data signals coupled to said duplexer means;

(d) means for receiving and demodulating voice and data signals coupled to said duplexer means;

(e) processor means for decoding received data, generating data to be transmitted, generating DTMF tones and controlling the overall operation of the subscriber unit including controlling the frequency response of switchable filters depending on whether data or voice is currently being received;

(f) summer means for combining data and tone information generated by said processor means;

(g) first filter means having an input for switchably controlling the transmit frequency response of the subscriber unit, said filter coupled between the modulator means and the summer means; and

(h) second filter means having an input for switchably controlling the receive frequency response of the subscriber unit, said filter disposed between said receiver means and said processing means.

6. The subscriber unit as recited in claim 2 wherein the frequency response of said second filter means is switched in response to a received signal having a variable data rate.

7. The subscriber unit as recited in claim 2 wherein the frequency response of said first filter means is switched in response to a generated signal which indicates the data rate of a signal to be transmitted.

8. The subscriber unit as recited in claim 2 wherein said first filter means is switchable between first and second frequency responses, wherein said first frequency response is characterized by a maximally flat Bessel function, and said second frequency response is characterized as a Chebychev function.

9. A duplex interconnect capable subscriber unit for use with a dispatch trunked radio system, said subscriber unit comprising:

(a) antenna means for receiving and transmitting an R.F. signal;

(b) duplexer means for coupling signals to said antenna means from a modulator circuit and to a demodulator circuit from said antenna means;

(c) modulating means for modulating voice and data signals coupled to said duplexer means;

(d) receiver means for receiving and demodulating voice and data signals coupled to said duplexer means;

(e) processor means for decoding at least some received data, generating at least some data to be transmitted, and for controlling at least some operating functions of said subscriber unit;

(f) first filter means responsive to said processor means for switchably controlling data transmission frequency response of said subscriber unit, wherein said first filter means has a frequency response that may be varied by said processor means to accomodate both voice mode and data mode of operation, and wherein said first filter means is operably coupled between said modulating means and said processor means; and

(g) second filter means responsive to said processor means for switchably controlling received data frequency response of said subscriber unit, wherein said second filter means has a frequency response that may be varied by said processor means to accomodate both voice mode and data mode of operation, and wherein said second filter means is operably coupled between said receiver means and said processor means.

10. The subscriber unit of claim 9 wherein said processor means further functions to generate DTMF tones.

11. The subscriber unit of claim 10 and further including summer means operably disposed between said processor means and said modulating means, for combining data and DTMF tone information and for providing such combined information to said modulating means.

12. The subscriber unit of claim 9 wherein said data as generated by said processor means can at least include a low speed data signal and a high speed data signal.

13. The subscriber unit of claim 12 wherein said processor means further functions to generate DTMF tones.

14. The subscriber unit of claim 13 and further including summer means operably disposed between said processor means and said modulator means, for combining said data signals and said DTMF tone information and for providing such combined information to said modulator means.

15. The subscriber unit of claim 9 wherein said second filter means has a frequency response that can be switched in response to variations in a received signal'"'"'s data rate.

16. The subscriber unit of claim 9 wherein said first filter means has a frequency response that can be switched in response to a signal indicating a data rate for a signal to be transmitted.

17. The subscriber unit of claim 16 wherein said frequency response for said first filter means can be switched between a first and second frequency response.