Claims
- 1. A sample rate conversion engine for upconversion, filtering with a set of filtering coefficients applied to delayed samples and down conversion comprising:
a multiplier accumulator unit; a sample delay line; a bank of coefficient registers, each containing a reduced set of the set of filtering coefficients to be applied to input samples for each of successive outputs; and control logic which for each of the successive outputs selects a reduced set of filtering coefficients from the bank of coefficient registers and a reduced set of samples from the sample delay line to be applied to the multiplier accumulator unit.
- 2. The sample rate conversion engine of claim 1, wherein the reduced set of the set of filtering coefficients is selected to include only filtering coefficients to be applied to non-zero samples.
- 3. The sample rate conversion engine of claim 2, wherein the reduced set of input samples are selected to only compute output samples.
- 4. The sample rate conversion engine of claim 1, wherein the bank of coefficient registers is programmable.
- 5. The sample rate conversion engine of claim 1, wherein a conversion rate is variable.
- 6. The sample rate conversion engine of claim 5, wherein the conversion rate is varied by modifying the reduced sets of filtering coefficients stored in the bank of coefficient registers.
- 7. The sample rate conversion engine of claim 1, wherein the number of reduced sets of filtering coefficients stored in the bank of coefficient register is dependent on a number of interpolated zero samples.
- 8. The sample rate conversion engine of claim 1, wherein the number of reduced sets of samples is dependent on the output sampling rate.
- 9. The sample rate conversion engine of claim 1, wherein a number of multipliers in the multiplier accumulator unit is fixed.
- 10. The sample rate conversion engine of claim 1, wherein the conversion ratio is P/Q, the number of multipliers is N and the number of sets of filtering coefficients is P, to compute successive Q output samples one of the sets of filtering coefficients is applied to each of Q sets of input samples in the multiplier accumulator unit.
- 11. The sample rate conversion engine of claim 1, wherein the conversion ratio is P/Q, the number of multipliers is N, the reduced set of the set of filtering coefficients stored in the bank is h[rP+nQ (mod P)] and a reduced set of input samples is x(nQ/P)−r] and a successive output y[n] is the product of the reduced set of filtering coefficients and the reduced set of input samples for r=0 to N−1.
- 12. A method of up converting, filtering with a set of filtering coefficients applied to delayed samples and down converting comprising:
storing reduced sets of the set of filtering coefficients to be applied to input samples for each of successive outputs; and for each of the successive outputs, selecting a reduced set of filtering coefficients and a reduced set of samples from a sample delay line to be applied to the multiplier accumulator unit.
- 13. The method of claim 12, wherein the bank of coefficient registers is programmable.
- 14. The method of claim 12, wherein a conversion rate is variable.
- 15. The method of claim 14, wherein the conversion rate is varied by modifying the reduced sets of filtering coefficients stored in the bank of coefficient registers.
- 16. The method of claim 12, wherein the number of reduced sets of filtering coefficients stored in the bank of coefficient register is dependent on a number of interpolated zero samples.
- 17. The method of claim 12, wherein the number of reduced sets of samples is dependent on the output sampling rate.
- 18. The method of claim 12, wherein a number of multipliers in the multiplier accumulator unit is fixed.
- 19. The method of claim 12, wherein the conversion ratio is P/Q, the number of multipliers is N and the number of sets of filtering coefficients is P, to compute successive Q output samples one of the sets of filtering coefficients is applied to each of Q sets of input samples in the multiplier accumulator unit.
- 20. The method of claim 12, wherein the conversion ratio is P/Q, the number of multipliers is N, the reduced set of filtering coefficients is h[rP+nQ (mod P) and a reduced set of input samples is x(nQ/P)−r] and a successive output y[n] is the product of the reduced set of filtering coefficients and the reduced set of input samples for r=0 to N−1.
- 21. A sample rate conversion engine for upconversion, filtering with a set of filtering coefficients applied to delayed samples and down conversion comprising:
means for storing, reduced sets of the set of filtering coefficients to be applied to input samples for each of successive outputs; and for each of the successive outputs, means for selecting a reduced set of filtering coefficients and a reduced set of samples from a sample delay line to be applied to the multiplier accumulator unit.
RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Application No. 60/424,375,filed on Nov. 6, 2002. The entire teachings of the above application are incorporated herein by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60424375 |
Nov 2002 |
US |