Spectrally shaped random signal

Patent metadata

Field	Value
Publication number	US-9929738-B2
Application number	US-201715427737-A
Country	US
Kind code	B2
Filing date	Feb 8, 2017
Priority date	Mar 4, 2016
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

An apparatus ( 100 ) comprises a signal generator ( 101 ) that is set up to produce a digital random signal ( 191 ). The apparatus ( 100 ) also comprises at least one filter element ( 102, 121, 122 ) that is set up to apply a high pass filter and a low pass filter to the digital random signal ( 191 ) in order to produce a spectrally shaped random signal ( 112 ). The apparatus ( 100 ) also comprises a modulator ( 103 ) that is set up to apply the spectrally shaped random signal ( 192 ) as dither.

First claim

The invention claimed is:

1. An apparatus comprising:
a signal generator that is configured to generate a digital pseudorandom signal;
at least one filter element that is connected in series with the signal generator and that is configured as a high pass filter and a low pass filter to generate a spectrally-shaped pseudorandom signal from the digital pseudorandom signal; and
a modulator that is connected in series with the at least one filter element and that is configured to receive an input signal and dither the input signal with the spectrally-shaped pseudorandom signal to generate an output signal.

2. The apparatus according to claim 1 , wherein the spectrally-shaped pseudorandom signal has a triangular probability density function.

3. The apparatus according to claim 1 , wherein the low pass filter is a Chebyshev filter.

4. The apparatus according to claim 1 , wherein the low pass filter comprises a recursive component.

5. The apparatus according to claim 1 , wherein the signal generator comprises a linear feedback shift register having a multiplicity of series-coupled storage elements, and wherein the at least one filter element is configured to implement the high pass filter and the low pass filter by combining a value of a first storage element of the multiplicity of series-coupled storage elements and a value of a second storage element of the multiplicity of series-coupled storage elements that is different than the first storage element.

6. The apparatus according to claim 1 , wherein the digital pseudorandom signal has a first word length, and wherein the spectrally-shaped pseudorandom signal has a second word length that is longer than the first word length.

7. The apparatus according to claim 6 , wherein the first word length is equal to one.

8. The apparatus according to claim 1 , further comprising a centering element that is configured to reduce a DC component of the digital pseudorandom signal.

9. The apparatus according to claim 1 , wherein the modulator is a digital modulator.

10. The apparatus according to claim 1 , wherein the modulator is an analog-to-digital converter.

11. The apparatus according to claim 1 , wherein the modulator is configured to dither the input signal only with the spectrally-shaped pseudorandom signal.

12. The apparatus according to claim 1 , further comprising a scaling element that is configured to scale the spectrally-shaped pseudorandom signal.

13. A method comprising:
producing, by a signal generator, a digital pseudorandom signal;
filtering, by at least one filter that is connected in series with the signal generator and that is configured as a high pass filter and a low pass filter, the digital pseudorandom signal to generate a spectrally-shaped pseudorandom signal from the digital pseudorandom signal; and
dithering, by a modulator that is connected in series with the at least one filter and that is configured to receive as input an input signal and the spectrally-shaped pseudorandom signal, the input signal with the spectrally-shaped pseudorandom signal to generate an output signal.

14. The method according to claim 13 , wherein the spectrally-shaped pseudorandom signal has a triangular probability density function.

15. The method according to claim 13 , wherein the low pass filter is a Chebyshev filter.

16. The method according to claim 13 , wherein the low pass filter comprises a recursive component.

17. The method according to claim 13 , wherein the signal generator comprises a linear feedback shift register having a multiplicity of series-coupled storage elements, and wherein filtering the digital pseudorandom signal to generate the spectrally-shaped pseudorandom signal from the digital pseudorandom signal comprises:
combining a value of a first storage element of the multiplicity of series-coupled storage elements and a value of a second storage element of the multiplicity of series-coupled storage elements that is different than the first storage element.

18. The method according to claim 13 , wherein the digital pseudorandom signal has a first word length, and wherein the spectrally-shaped pseudorandom signal has a second word length that is longer than the first word length.

19. The method according to claim 13 , further comprising reducing a DC component of the digital pseudorandom signal.

20. The method according to claim 13 , further comprising dithering the input signal only with the spectrally-shaped pseudorandom signal to generate the output signal.

Assignees

• Infineon Technologies Ag

Inventors

• Straeussnigg Dietmar

Classifications

• H03M1/0854 Primary

  of quantisation noise · CPC title

• H03K3/84

  Generating pulses having a predetermined statistical distribution of a parameter, e.g. random pulse generators · CPC title

• H03M3/50 Primary

  Digital/analogue converters using delta-sigma modulation as an intermediate step (digital delta-sigma modulators per se H03M7/3004) · CPC title

• H03M1/0641

  the dither being a random signal · CPC title

• H03M3/33

  the dither being a random signal · CPC title