Multiplexed wireless receiver and transmitter

• US 7,450,911 B1
• Filed: 03/29/2007
• Issued: 11/11/2008
• Est. Priority Date: 12/21/2003
• Status: Expired due to Term

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Redpine Signals Incorporated (Silicon Laboratories Incorporated)
• Inventors: Venkatesh, Narasimhan
• Primary Examiner(s): Nguyen; Duc M
• Application Number:
  US11/731,718
• Time in Patent Office: 593 Days
• Field of Search: 455/73, 455 901- 903, 375/219, 375/377
• US Class Current: 455/73
• CPC Class Codes: H04B 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
• CPC Class Codes: H04L 27/206 using a pair of orthogonal carriers, e.g. quadrature carriers

Abstract

A baseband receiver having quadrature analog outputs and a plurality of analog control and status signals and a transmit modulator having analog quadrature inputs and a plurality of analog control and status signals are coupled to a transmit processor having a digital output and a plurality of digital control and status signals and to a receive processor having a digital input and a plurality of digital control and status signals by multiplexing analog to digital converters and digital to analog converters such that during a receive time the converters are used for a receive purpose and during a transmit time, the converters are used for a transmit purpose.

Claims

1. A signal processing system for a wireless communication system, said signal processing system comprising:

a baseband receiver having two or more control inputs and a status output;

a transmit modulator having a quadrature input, one or more control inputs, and a status output;

a baseband transmit processor having a quadrature output, a control output, a status input, and a transmit enable output;

a baseband receive processor having at least two control outputs and a status input;

a first multiplexer having an output, said output selecting either;

one of said baseband receive processor control outputs

or one of said baseband transmit processor quadrature outputs, said first multiplexer making a selection based on said transmit enable, said first multiplexer output coupled to a first digital to analog converter (DAC), said first DAC output coupled to one of said transmit modulator quadrature inputs and also to one of said baseband receiver control inputs;

a second multiplexer having an output, said output selecting either;

other said baseband receive processor control output or the other said baseband transmit processor quadrature output, said second multiplexer making a selection based on said transmit enable, said second multiplexer output coupled to the input of a second digital to analog converter (DAC), and delivering the output of said second DAC to the other of said transmit modulator quadrature inputs and also to the other of said baseband receiver control inputs;

a third multiplexer having an output, said output selecting either said baseband receiver status output or said transmit modulator output, said third multiplexer output selection based on said transmit enable, said third multiplexer output coupled to a first analog to digital converter, the output of said analog to digital converter coupled to said baseband receive processor status input and also to said baseband transmit processor status input.

2. The signal processing system of claim 1 where said first multiplexer couples one of said baseband receive processor control outputs to said first DAC when said transmit enable is not active.

3. The signal processing system of claim 2 where at least one said baseband receive processor control input is a gain control input.

4. The signal processing system of claim 1 where said second multiplexer couples one of said baseband receive processor control outputs to said second DAC when said transmit enable is not active.

5. The signal processing system of claim 4 where said baseband receive processor control outputs is a gain control.

6. The signal processing system of claim 1 where said second multiplexer couples one of said baseband transmit processor quadrature outputs to said second DAC when said transmit enable is active.

7. The signal processing system of claim 1 where said third multiplexer couples one of said baseband receiver status outputs to said ADC when said transmit enable is not active.

8. The signal processing system of claim 7 where said one of baseband receiver status outputs is receive signal strength indication.

9. The signal processing system of claim 1 where said third multiplexer couples said transmit modulator status output to said first ADC when said transmit enable is active.

10. The signal processing system of claim 9 where said transmit modulator status output is a transmit power strength.

11. The signal processing system of claim 1 where at least one of said baseband receive processor or said baseband transmit processor is a digital circuit.

12. The signal processing system of claim 11 where said digital circuit is an integrated circuit.

13. The signal processing system of claim 11 where said digital circuit is a field programmable gate array (FPGA).

14. The signal processing system of claim 1 where said first multiplexer includes a test input which is coupled to said first DAC or to said DAC, selectable by said transmit enable.

15. The signal processing system of claim 1 where said second multiplexer includes a test input which is coupled to said first DAC or to said second DAC, selectable by said transmit enable.

25. The signal processing system of claim 1 or 16 where said baseband receiver quadrature outputs and said transmit modulator quadrature inputs are analog signals.

26. The signal processing system of claim 1 or 16 where said baseband receive processor quadrature inputs and said baseband transmit processor outputs are digital signals having more than one bit of width.

16. A signal processing system for a wireless communications system, said signal processing system comprising:

a baseband receiver having two or more control inputs and a status output;

a transmit modulator having a quadrature input, one or more control inputs, and at least one status output;

a baseband receive processor having at least two control outputs;

a baseband transmit processor having a quadrature output, a control output, and a transmit enable output;

a first multiplexer having an output, said output selecting one of;

said baseband receive processor control output or one of said baseband transmit processor quadrature outputs, said first multiplexer making a selection based on said transmit enable, said first multiplexer output coupled to a first digital to analog converter (DAC), said first DAC output coupled to one of said transmit modulator quadrature inputs and also to one of said baseband receiver control inputs;

a second multiplexer having an output, said output selecting either;

other said baseband receive processor control output or the other of said baseband transmit processor quadrature outputs, said second multiplexer making a selection based on said transmit enable, said second multiplexer output coupled to a second digital to analog converter (DAC),

said second DAC output coupled to the other of said transmit modulator quadrature inputs and also to the other of said baseband receiver control inputs.

17. The signal processing system of claim 16 where said first multiplexer couples one of said baseband receive processor control outputs to said first DAC when said transmit enable is not active.

18. The signal processing system of claim 17 where at least one said baseband receive processor control output is a gain control signal.

19. The signal processing system of claim 16 where said first multiplexer couples one of said baseband transmit processor quadrature outputs to said first DAC when said transmit enable is active.

20. The signal processing system of claim 16 where said second multiplexer couples one of said baseband receive processor control outputs to said second DAC when said transmit enable is not active.

21. The signal processing system of claim 20 where at least one said baseband receive processor control outputs is a gain control signal.

22. The signal processing system of claim 16 where said second multiplexer couples one of said baseband transmit processor quadrature signals outputs to said second DAC when said transmit enable is active.

23. The signal processing system of claim 16 where said first multiplexer includes a test input which is coupled to said first DAC or to said DAC, selectable by said transmit enable.

24. The signal processing system of claim 16 where said first multiplexer includes a test input which is coupled to said first DAC or to said DAC, selectable by said transmit enable.

27. A signal processing system having:

a receiver for receiving a wireless signal and generating a quadrature baseband output, said receiver generating a receive signal strength indicator (RSSI) proportional to received signal strength and accepting a receiver gain control input;

a transmitter for accepting a baseband quadrature input and modulating to a carrier frequency, said transmitter accepting a transmit gain control and generating a transmit power output;

a transmit enable indicating that said transmitter is active during a transmit interval, and not active at other times;

a baseband signal processor for accepting a digitized quadrature receiver input, a receive signal strength input, a transmit signal strength input, and generating a digitized quadrature transmit output, said baseband signal processor also generating said transmit enable, a receive gain control output, and a transmit gain control output;

a first digital to analog converter (DAC) having an output coupled to one of said transmitter quadrature inputs and also to said baseband receiver gain control input, said first DAC input coupled to a first multiplexer selecting said baseband signal processor gain control output when said transmit enable is inactive and to one of said baseband signal processor quadrature transmit outputs when said transmit enable is active;

a first analog to digital converter (ADC) having an output coupled to said receive signal strength input and also to said transmit signal strength input, said first ADC input coupled to a second multiplexer selecting said baseband receive signal strength indicator when said transmit enable is not active and said transmitter power output when said transmit enable is active;

a second digital to analog converter (DAC) having an input coupled to other said baseband signal processor quadrature transmit output and an output coupled to the other said transmitter quadrature input.