Preserving phase shift in spatial filtering
View Patent ↗For preserving phase shift in spatial filtering is disclosed, an electronic device includes a microphone array. A filtering module spatially filters a plurality of received audio signals from the microphone array to increase the signal-to-noise ratio in one or more corresponding output audio signals. A phase module preserves a phase shift of at least one received audio signal in the corresponding output audio signal.
1. An apparatus comprising:
an electronic device comprising a microphone array;
a filtering module spatially filtering a plurality of received audio signals from the microphone array to increase the signal-to-noise ratio in one or more corresponding output audio signals; and
a phase module preserving a phase shift of at least one received audio signal in the corresponding output audio signal, wherein the filtering module and the phase module comprise one or more of semiconductor hardware and a memory storing machine readable code and a processor executing the machine readable code.
2. The apparatus of claim 1 , wherein at least one of the one or more output audio signals is a mono output audio signal shifted by a predetermined phase.
3. The apparatus of claim 1 , wherein the one or more output audio signals comprise an output vector of spatially filtered output audio signals with preserved phase shifts.
4. The apparatus of claim 1 , wherein the one or more output audio signals is a product of an input vector and a steering matrix.
5. The apparatus of claim 4 , wherein an output vector VO of the one or more output audio signals is a product of coefficients h, the input vector VI comprising the plurality of received audio signals, and the steering matrix VM, VO=(h*VM)*VI.
6. The apparatus of claim 5 , wherein the steering matrix VM is calculated as a product of an adjustment vector g and a steering vector VS, VM=g*VS.
7. A method comprising:
spatially filtering a plurality of received audio signals to increase the signal-to-noise ratio in one or more corresponding output audio signals; and
preserving a phase shift of at least one received audio signal in the corresponding output audio signal.
8. The method of claim 7 , wherein at least one of the one or more output audio signals is a mono output audio signal shifted by a predetermined phase.
9. The method of claim 7 , wherein the one or more of output audio signals comprise an output vector of spatially filtered output audio signals with preserved phase shifts.
10. The method of claim 7 , wherein the one or more output audio signals is a product of an input vector and a steering matrix.
11. The method of claim 10 , wherein an output vector VO of the one or more output audio signals is a product of coefficients h, the input vector VI comprising the plurality of received audio signals, and the steering matrix VM, VO=(h*VM)*VI.
12. The method of claim 11 , wherein the steering matrix VM is calculated as a product of an adjustment vector g and a steering vector VS, VM=g*VS.
13. The method of claim 12 , wherein g is [1, e +jτ , e +j2τ , . . . e +j(N-1)τ ] T , VS is [1, e −jτ , e −j2τ , . . . e −j(N-1)τ ], j is an imaginary number, and i is a phase shift for each audio signal.
14. The method of claim 1 , wherein at least one of the plurality of received audio signals is a reference signal for at least one other received audio signal.
15. The method of claim 1 , further comprising digitizing the plurality of received audio signals.
16. A program product comprising a non-transitory computer readable storage medium storing machine readable code executable by a processor to perform:
spatially filtering a plurality of received audio signals to increase the signal-to-noise ratio in one or more corresponding output audio signals; and
preserving a phase shift of at least one received audio signal in the corresponding output audio signal.
17. The program product of claim 16 , wherein at least one of the one or more output audio signals is a mono output audio signal shifted by a predetermined phase.
18. The program product of claim 16 , wherein the one or more output audio signals comprises an output vector of spatially filtered output audio signals with preserved phase shifts.
19. The program product of claim 16 , wherein the one or more output audio signals is a product of an input vector and a steering matrix.
20. The program product of claim 19 , wherein an output vector VO of the one or more output audio signals is a product of coefficients h, an input vector VI comprising the plurality of received audio signals, and the steering matrix VM, VO=(h*VM)*VI.