System and methods for data compression and nonuniform quantizers

• US 10,686,466 B2
• Filed: 07/03/2019
• Issued: 06/16/2020
• Est. Priority Date: 10/05/2017
• Status: Active Grant

• Current Assignee: Cable Television Laboratories Incorporated
• Original Assignee: Cable Television Laboratories Incorporated
• Inventors: Xu, Mu, Jia, Zhensheng, Wang, Jing, Campos, Luis Alberto
• Primary Examiner(s): Pierre, Peguy Jean
• Application Number:
  US16/503,316
• Publication Number:
  US 20190326926A1
• Time in Patent Office: 349 Days
• Field of Search: 341143, 341155, 341120, 341118
• CPC Class Codes: G06F 17/16 Matrix or vector computation , e.g. matrix-matrix or matrix-vector multiplication, matrix factorization matrix transposition G06F7/78
• CPC Class Codes: G06F 17/17 Function evaluation by approximation methods, e.g. inter- or extrapolation, smoothing, least mean square method G06F17/18 takes precedence ; interpolation for numerical control G05B19/18
• CPC Class Codes: H03M 1/008 among different conversion characteristics, e.g. between mu-255 and a-laws
• CPC Class Codes: H03M 1/0626 by filtering
• CPC Class Codes: H03M 1/1265 Non-uniform sampling
• CPC Class Codes: H03M 1/664 Non-linear conversion not otherwise provided for in subgroups of H03M1/66
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/6583 Normalization other than scaling, e.g. by subtraction
• CPC Class Codes: H03M 5/06 Code representation, e.g. transition, for a given bit cell depending only on the information in that bit cell
• CPC Class Codes: H03M 5/12 Biphase level code, e.g. split phase code, Manchester code; Biphase space or mark code, e.g. double frequency code
• CPC Class Codes: H03M 7/3044 Conversion to or from differential modulation with several bits only, i.e. the difference between successive samples being coded by more than one bit, e.g. differential pulse code modulation [DPCM] H03M7/3004 takes precedence; voice coding G10L19/00; image coding H04N19/00
• CPC Class Codes: H03M 7/3055 Conversion to or from Modulo-PCM
• CPC Class Codes: H03M 7/3059 Digital compression and data reduction techniques where the original information is represented by a subset or similar information, e.g. lossy compression

Abstract

A method for differentiator-based compression of digital data includes (a) using a subtraction module, subtracting a predicted signal from a sample of an original signal to obtain an error signal, (b) using a quantization module, quantizing the error signal to obtain a quantized error signal, and (c) generating the predicted signal using a least means square (LMS)-based filtering method.

Claims

1. A method for differentiator-based compression of digital data, comprising:

generating a predicted signal using an adaptive filtering method, wherein generating the predicted signal using the adaptive filtering method comprises multiplying a tap-weight vector by an original data vector to generate the predicted signal, the original data vector comprising N sequential samples of an original signal, N being an integer greater than or equal to one;

using a subtraction module, subtracting the predicted signal from a sample of the original signal to obtain an error signal;

using a non-uniform quantizer, quantizing the error signal to obtain a quantized error signal; and

updating the tap-weight vector by adding to the tap-weight vector a product of (a) a step size, (b) the error signal, and (c) a complex conjugate of the original data vector.

2. The method of claim 1, wherein N is an integer greater than one.

3. The method of claim 1, wherein quantizing the error signal to obtain the quantized error signal comprises using a non-uniform quantizing algorithm to quantize the error signal.

4. The method of claim 3, wherein the non-uniform quantizing algorithm comprises a relaxed Lloyd algorithm.

5. The method of claim 1, wherein the steps of generating, subtracting, and quantizing are performed by a processor executing computer-readable instructions stored in a memory.

6. A method for generating a signal for transmission over a transmission medium, comprising:

sampling an analog original signal to obtain a sample of the original signal;

using the method of claim 1, obtaining a quantized error signal from the sample of the original signal;

mapping the quantized error signal from U bits to V bits to obtain a mapped error signal, U and V each being respective integers, and U being greater than V; and

modulating a carrier signal according to the mapped error signal to obtain the signal for transmission over the transmission medium.

7. A method for receiving a signal, comprising:

receiving a transmission signal from a transmission medium;

demodulating the transmission signal to obtain a demodulated signal;

mapping the demodulated signal from V to U bits to obtain a quantized error signal, U and V each being respective integers, and U being greater than V;

decompressing the quantized error signal to obtain a quantized original signal by;

generating a predicted signal using an adaptive filtering method, and

using an addition module, adding the predicted signal to a quantized error signal to obtain the quantized original signal; and

converting the quantized original signal into an analog output signal.

8. The method of claim 7, wherein generating the predicted signal using the adaptive filtering method comprises multiplying a tap-weight vector by an original data vector to generate the predicted signal, the original data vector comprising N sequential samples of the original signal, N being an integer greater than or equal to one.

9. The method of claim 8, wherein N is an integer greater than one.

10. The method of claim 7, wherein the steps of adding and generating are performed by a processor executing computer-readable instructions stored in a memory.

11. A method for transmitting data, comprising:

sampling an analog original signal to obtain a sample of the original signal;

generating a first predicted signal using a first least means square (LMS)-based filtering method;

subtracting the first predicted signal from the sample of the original signal to obtain an error signal;

quantizing the error signal to obtain a quantized error signal;

mapping the quantized error signal from U bits to V bits to obtain a mapped error signal, U and V each being respective integers, and U being greater than V;

modulating a carrier signal according to mapped error signal to obtain a transmission signal;

transmitting the transmission signal from a first location to a second location using a transmission medium;

demodulating the transmission signal to obtain a demodulated signal;

mapping the demodulated signal from V to U bits to obtain the quantized error signal;

generating a second predicted signal using a second LMS-based filtering method;

using an addition module, adding the second predicted signal to the quantized error signal to obtain a quantized original signal; and

converting the quantized original signal into an analog output signal.

12. The method of claim 11, wherein generating the first predicted signal using the first LMS-based filtering method comprises multiplying a tap-weight vector by an original data vector to generate the first predicted signal, the original data vector comprising N sequential values of the original signal, N being an integer greater than or equal to one.

13. The method of claim 12, further comprising updating the tap-weight vector by adding to the tap-weight vector a product of (a) a step size, (b) the error signal, and (c) a complex conjugate of the original data vector.

14. The method of claim 13, wherein N is an integer greater than one.

15. The method of claim 11, wherein quantizing the error signal to obtain a quantized error signal comprises using a non-uniform quantizing algorithm to quantize the error signal.

16. The method of claim 15, wherein the non-uniform quantizing algorithm comprises a relaxed Lloyd algorithm.

17. The method of claim 11, wherein:

the step of modulating is performed by a transmitting device; and

the step of demodulating is performed by a receiving device.