Methods and systems for efficient filtering of digital signals
AssigneeGeneral Instrument Corporation
InventorChanchal Chatterjee
Life of this patent
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Abstract
A method in a signal processor for filtering samples in a digital signal is provided. An approximate filtered sample is generated as a function of less than four samples of the digital signal. A correction is generated as a function of the less than four samples, and a filtered sample is generated by modifying the approximate filtered sample with the correction.
Claims46
A method in a signal processor for filtering samples in a digital signal, the method comprising:
- generating an approximate filtered sample as a function of less than four samples of the digital signal;
- generating a correction as a function of the less than four samples;
- and
- generating a filtered sample by modifying the approximate filtered sample with the correction.
A method in a signal processor for filtering samples in a digital signal, the method comprising:
- generating an approximate filtered sample as a function of a first sample, A, a second sample, B, a third sample, C, and a fourth sample, D, wherein A, B, C, and D are fixed-point numbers;
- generating a correction as ((A{circle over (+)}B)AND(C{circle over (+)}D))OR(M{circle over (+)}N), wherein M=A+B+1>>1 and N=C+D+1>>1;
- masking the correction;
- and
- generating a filtered sample by modifying the approximate filtered sample with the correction.
A method in a signal processor for filtering samples in a digital signal, the method comprising:
- generating an approximate filtered sample as a function of a first sample, A, a second sample, B, a third sample, C, and a fourth sample, D, wherein A, B, C, and D are integers;
- generating a correction as (A{circle over (+)}B)OR(C{circle over (+)}D)OR(M{circle over (+)}N), wherein M=A+B+1>>1 and N=C+D+1>>1;
- masking the correction;
- and
- generating a filtered sample by modifying the approximate filtered sample with the correction.
A method in a signal processor for filtering samples in a digital signal, the method comprising:
- generating an approximate filtered sample as a function of a first sample, A, a second sample, B, a third sample, C, and a fourth sample, D, wherein A, B, C, and D are fixed-point numbers;
- generating a correction as (A{circle over (+)}B)OR(C{circle over (+)}D)OR(M{circle over (+)}N), wherein M=A+B+1>>1 and N=C+D+1>>1;
- masking the correction;
- and
- generating a filtered sample by modifying the approximate filtered sample with the correction.
A method in a signal processor for filtering samples in a digital signal, the method comprising:
- 11 generating M1 = (A+B+1)>>1, wherein A and B are samples in the digital signal;
- generating M2 = (C+D+1)>>1, wherein C and D are samples in the digital signal;
- generating M3 = (E+F+1)>>1, wherein E and F are samples in the digital signal;
- generating M4 = (G+H+1)>>1, wherein G and H are samples in the digital signal;
- generating N1 = (M1+(M3>>1)+(M3>>2))>>2;
- generating N2 = (M2+(M2>>1)+(M4>>2))>>2;
- and generating a filtered sample as M1+N1−N2.
A computer program product comprising:
- a computer readable storage medium having computer program code embodied therein for quantizing a digital signal, the computer program code comprising:
- code for generating an approximate filtered sample as a function of less than four samples of the digital signal;
- code for generating a correction as a function of the less than four samples;
- and
- code for generating a filtered sample by modifying the approximate filtered sample with the correction.
A system for filtering samples in a digital signal, the system comprising:
- a memory that stores samples in the digital signal;
- and
- a processor coupled to the memory and operable to perform the steps of:
- A) generating an approximate filtered sample as a function of less than four samples of the digital signal;
- B) generating a correction as a function of the less than four samples;
- and
- C) generating a filtered sample by modifying the approximate filtered sample with the correction.
A computer program product comprising:
- a computer readable storage medium having computer program code embodied therein for quantizing a digital signal, the computer program code comprising:
- code for generating an approximate filtered sample as a function of a first sample, A, a second sample, B, a third sample, C, and a fourth sample, D, wherein A, B, C, and D are fixed-point numbers;
- code for generating a correction as ((A{circle over (+)}B)AND(C{circle over (+)}D))OR(M{circle over (+)}N), wherein M=A+B+1>>1 and N=C+D+1>>1;
- code for masking the correction;
- and
- code for generating a filtered sample by modifying the approximate filtered sample with the correction.
A system for filtering samples in a digital signal, the system comprising:
- a memory that stores samples in the digital signal;
- and
- a processor coupled to the memory and operable to perform the steps of:
- A) generating an approximate filtered sample as a function of a first sample, A, a second sample, B, a third sample, C, and a fourth sample, D, wherein A, B, C, and D are fixed-point numbers;
- B) generating a correction as ((A{circle over (+)}B)AND(C{circle over (+)}D))OR(M{circle over (+)}N), wherein M=A+B+1>>1 and N=C+D+1>>1;
- C) masking the correction;
- and
- D) generating a filtered sample by modifying the approximate filtered sample with the correction.
Dependencies are inferred from the claim text.