Digital signal processor transceiver

• US 7,103,108 B1
• Filed: 05/17/2002
• Issued: 09/05/2006
• Est. Priority Date: 05/17/2001
• Status: Expired due to Fees

• Current Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Beard, Paul
• Primary Examiner(s): Bocure, Tesfaldet
• Assistant Examiner(s): Panwalkar, Vineeta
• Application Number:
  US10/150,731
• Time in Patent Office: 1,572 Days
• Field of Search: 375/295, 375/296, 375/302, 375/303, 375/305, 375/316, 375/329, 375/332, 375/334, 375/336, 375/219, 375/340, 332100-105, 711 1- 6, 711100-102, 711/109, 711/111
• US Class Current: 375/295
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/122 using digital generation of carrier signals digital function generators G06F1/02, H04L17/10; generating pulses having stepped portions using digital techniques H03K4/026

Abstract

A digital signal processor transceiver uses a finite impulse response filter memory to construct a phase integrated angle at each clock cycle. The FIR filter memory is addressed by a multibit pattern and a time count which are used in conjunction to determine the address. Each data word of the FIR filter memory represents the sum of two tap points multiplied by their tap coefficients. Several of the most significant bits of the phase integrated angle are used to address look up tables for the signal'"'"'s sine and cosine values. The address for the cosine look up table may further be phase compensated. Filter types other than a FIR filter may be used.

Claims

1. A method of selecting a frequency in a digital signal processor, comprising the steps of:

inputting a series of data bits;

combining each data bit with at least one other data bit and with a series of counts from a counter that counts to a particular number, to generate said particular number of addresses for each data bit in said series of data bits;

using said addresses to determine a plurality of first values associated with each data bit and at least one previously inputted data bit;

successively adding the first values to a sum; and

on each successive adding of the first values of the sum, using at least a portion of the sum to provide an in-phase value and a quadrature value such that a phase integrated angle at each clock cycle may be produced.

2. The method of claim 1, wherein at least a portion of the sum addresses a first memory which contains an in-phase value and a second memory which contains a quadrature value.

3. The method of claim 2, wherein the first memory contains sine values and the second memory contains cosine values.

4. The method of claim 1, wherein the series of input data bits are output by a baseband signal.

5. The method of claim 1, wherein said plurality of said data bits are three in number.

6. The method of claim 5, wherein said plurality of first values are stored in a Gaussian finite impulse response memory.

7. The method of claim 6, wherein said Gaussian finite impulse response memory is a read only memory.

8. The method of claim 1, wherein said sum is stored in a latch.

9. The method of claim 1, wherein the count from a said counter and a data bit and at least one previously input data bit form the complete address to access one of the plurality of first values.

10. A method of selecting a frequency in a digital signal processor, comprising the steps of:

inputting a series of data bits;

combining a plurality of said data bits with a series of counts from a counter that counts to a particular number, to generate said particular number of addresses for each bit in said series of inputted bits;

using said addresses to determine a series of values from one or more taps in a finite impulse response filter in which each value of the series is individually and successively added to a sum;

using at least a portion of the sum to determine an in-phase value and a quadrature value.

11. The method of claim 10, wherein said series of data bits is from a baseband, time delayed with respect to one another.

12. The method of claim 11, wherein each of said values of said series of values represents an addition of two products of a single tap and its corresponding coefficient.

13. The method of claim 10, wherein each of said series of values is determined by a pattern of bits including a recently inputted bit.

14. The method of claim 13, wherein said pattern of bits is formed of multiple bits, including the recently input bit.

15. A method for selecting a frequency in a digital signal processor, comprising the steps of:

inputting a series of bits;

clocking a counter to yield a count value; and

using a plurality of said bits and each count value of said counter as an address to determine a plurality of filter values for each bit in said series of bits.

16. The method of claim 15, further comprising phase integrating a plurality of said filter values to yield a sum.

17. The method of claim 16, wherein said filter values represents multiple taps of the filter.

18. The method of claim 17, further comprising using most significant bits of said sum to derive a sine value.

19. A method for selecting a frequency in a digital signal processor, comprising the steps of:

inputting a series of bits;

clocking a counter to yield a count value;

using a plurality of said bits and the count value as an address to determine a plurality of filter values for each bit in said series, said filter values representing multiple taps of the filter; and

using the most significant bits of said sum to derive a sine value, and further comprising using a phase correction process on the most significant bits and using a resulting output of the phase correction process to derive a cosine value.

20. The method of claim 19, wherein the said sine value is an in-phase value and the cosine value is a quadrature value.

21. A digital signal processor transceiver, comprising:

inputting a series of data bits;

combining each data bit with at least one other data bit and with a series of counts from a counter that counts to a particular number to generate a series of addresses having said particular number of addresses for each data bit,

means using said addresses for selecting a value representing two or more taps of a filter;

means for phase integrating the value to provide a sum; and

means for using a portion of the sum to determine an in-phase value and a quadrature value.

22. The digital signal processor transceiver of claim 21, wherein the means for using the sum includes a means for phase angle correction.

23. The digital signal processor transceiver of claim 21, wherein the means for selecting a value includes a means for storing a bit pattern from a baseband.

24. The digital signal processor transceiver of claim 23, wherein the means for selecting a value further includes a means for counting.

25. The digital signal processor transceiver of claim 21, wherein the means for selecting a value includes means for storing and means for generating an address in which the address is used to retrieve the tap points of a desired filter response from the means for storing.

26. The digital signal processor transceiver of claim 25, wherein the means for storing being loadable to permit recalibration of the tap points of the desired filter response.

27. The digital signal processor transceiver of claim 25, wherein the desired filter response being a Gaussian finite impulse response (FIR) filter.

28. The digital signal processor transceiver of claim 27, wherein coefficients of the Gaussian FIR filter are derived through preprocessing of the filter characteristics at a receiver by an analysis of an inverse transfer function of the transceiver.

29. The digital signal processor transceiver of claim 27, wherein each word of the means for storing corresponding to the sum of the products of two tap points and their corresponding coefficients.

30. The digital signal processor transceiver of claim 29, wherein the coefficients being determined by a tap weight algorithm and being updated either periodically or as needed to reasonably track changes in the RF propagation characteristics.

31. The digital signal processor transceiver of claim 30, wherein the Gaussian FIR filter having 24 taps and the transceiver being part of a BLUETOOTH communications device in which the bandwidth-time (BT) product is 0.5.

32. The digital signal processor transceiver of claim 31, wherein each word of the means for storing providing an integrated phase angle.

33. The digital signal processor transceiver of claim 21, wherein the means for using a portion of the sum includes a means for determining sine and cosine values for an accumulated phase angle.

34. The digital signal processor of claim 33, wherein the means for determining sine and cosine values includes software routine, hardware, memory, and a look up table.

35. A digital signal processor transceiver, comprising:

a latch for an address which includes data bits from a baseband and a count value from a counter,

a first memory for providing an angle value corresponding to said address,

an adder for phase integrating said angle value to form a sum, and

a second memory containing sine values, a phase corrector, and a third memory contain cosine values, wherein the most significant bits from the sum address the second memory and are modified to provide an address for the third memory.

36. The digital signal processor transceiver of claim 35, wherein said first memory is a Gaussian finite impulse response read only memory, said second memory is a look up table, and said third memory is a look up table.