Nonlinear digital signal processor
View Patent ↗A digital signal processor (DSP) comprises an input terminal configured to receive an input, an adaptive nonlinear phase filter coupled to the input terminal, the adaptive nonlinear phase filter having a time-varying phase response, and an adaptive nonlinear amplitude filter coupled to the input terminal, the adaptive nonlinear amplitude filter having a time-varying amplitude response. A method of processing a signal comprises receiving the signal, sending the signal to an adaptive nonlinear phase filter, the adaptive nonlinear phase filter having a time-varying phase response, and sending the signal to an adaptive nonlinear amplitude filter, the adaptive nonlinear amplitude filter having a time-varying amplitude response.
1. A digital signal processor (DSP) comprising:
an input terminal configured to receive an input;
an adaptive nonlinear phase filter coupled to the input terminal, the adaptive nonlinear phase filter having a time-varying phase response; and
an adaptive nonlinear amplitude filter coupled to the input terminal, the adaptive nonlinear amplitude filter having a time-varying amplitude response.
2. The DSP of claim 1 , further comprising a combiner to combine the output of the adaptive nonlinear phase filter and the output of the adaptive nonlinear amplitude filter.
3. The DSP of claim 1 , wherein the adaptive nonlinear phase filter has an amplitude response that is approximately constant over time.
4. The DSP of claim 1 , wherein the adaptive nonlinear amplitude filter has a phase response that is approximately constant over time.
5. The DSP of claim 1 , wherein the adaptive nonlinear phase filter includes an infinite impulse response (IIR) filter.
6. The DSP of claim 1 , wherein the adaptive nonlinear phase filter includes an infinite impulse response (IIR) filter whose time domain function is
r n ã 0 (y n −r n−N )+ã 1 (y n−1 −r n−N+1 )+ . . . +y n−N .
7. The DSP of claim 1 , wherein the adaptive nonlinear amplitude filter includes a finite impulse response (FIR) filter.
8. The DSP of claim 7 , wherein the FIR filter has a filter coefficient that is a time-varying function of the input to the FIR filter.
9. The DSP of claim 7 , wherein the FIR filter has the form
u
n
=
∑
i
=
0
M
w
~
i
y
n
-
i
,
wherein {tilde over (w)} is a time-varying function of the input signal.
10. The DSP of claim 8 , wherein the time-varying function is a first order function of the input to the FIR filter.
11. A method for processing a signal, comprising:
receiving the signal as an input to a digital signal processor (DSP);
sending the signal to an adaptive nonlinear phase filter, the adaptive nonlinear phase filter having a time-varying phase response; and
sending the signal to an adaptive nonlinear amplitude filter, the adaptive nonlinear amplitude filter having a time-varying amplitude response.
12. The method of claim 11 , further comprising combining the output of the adaptive nonlinear phase filter and the output of the adaptive nonlinear amplitude filter.
13. The method of claim 11 , wherein the adaptive nonlinear phase filter has an amplitude, response that is approximately constant over time.
14. The method of claim 11 , wherein the adaptive nonlinear amplitude filter has a phase response that is approximately constant over time.
15. The method of claim 11 , wherein the adaptive nonlinear phase filter includes an infinite impulse response (IIR) filter.
16. The method of claim 11 , wherein the adaptive nonlinear phase filter includes an infinite impulse response (IIR) filter whose time domain function is
r n ã 0 (y n −r n−N )+ã 1 (y n−1 −r n−N+1 )+ . . . +y n−N .
17. The method of claim 11 , wherein the adaptive nonlinear amplitude filter includes a finite impulse response (FIR) filter.
18. The method of claim 17 , wherein the FIR filter has a filter coefficient that is a time-varying function of the input to the FIR filter.
19. The method of claim 17 , wherein the FIR filter has the form
u
n
=
∑
i
=
0
M
w
~
i
y
n
-
i
,
wherein {tilde over (w)} i is a time-varying function of the input signal.
20. The method of claim 18 , wherein the time-varying function is a first order function of the input to the FIR filter.
21. A computer program product for processing a signal, the computer program product being embodied in a computer readable medium and comprising computer instructions for:
receiving the signal;
sending the signal to an adaptive nonlinear phase filter, the adaptive nonlinear phase filter having a time-varying phase response; and
sending the signal to an adaptive nonlinear amplitude filter, the adaptive nonlinear amplitude filter having a time-varying amplitude response.