Patent ID: 9245520
Filing Date: 2016-01-26
CPC Classification: G10K,H04L,H04S

Claim Text:
1. Reverberator for reverberating an audio signal, comprising: a feedback delay loop processor for delaying at least two different frequency subband signals representing the audio signal by different loop delays to acquire reverberated frequency subband signals, wherein each of the at least two different frequency subband signals is a different time-frequency tile derived from a time domain audio signal, wherein the feedback delay loop processor comprises for a first frequency subband signal of the at least two frequency subband signals a first delay line comprising a first plurality of delay line taps providing signals delayed by different tap delays, a first feedback loop connected to the first delay line and a first combiner for combining signals output by the first plurality of delay line taps, and wherein the feedback delay loop processor comprises for a second different frequency subband signal of the at least two frequency subband signals a second delay line comprising a second plurality of delay line taps providing signals delayed by different tap delays, a second feedback loop connected to the second delay line and a second combiner for combining signals output by the second plurality of delay line taps, wherein the feedback delay loop processor comprises, for each frequency subband signal, a feedback loop and a diffuseness filter comprising a plurality of delay line taps, wherein the feedback loop comprises a delay element determining the loop delay for the frequency subband signal to acquire a feedback signal, and wherein the feedback loop comprises an adder for adding the frequency subband signal and the feedback signal, the adder being connected to the diffuseness filter, wherein the delay elements are different for the at least two different frequency subband signals, wherein the diffuseness filter or the delay line connected to the feedback loop and the combiner are configured as a sparse filter, wherein the sparse filter comprises a filter tap density, wherein a filter impulse response of the sparse filter approximates a predetermined energy envelope, wherein the sparse filter comprises a plurality of phase modification units, wherein each phase modification unit of the plurality of phase modification units is directly connected to an individual delay line tap of the plurality of delay line taps, and wherein each phase modification unit is configured to apply a multiplication-free phase operation to a corresponding signal output by the individual delay line tap, wherein the diffuseness filter or the delay line are complex-valued devices, and wherein each phase modification unit of the plurality of phase modification units comprises a first phase modification unit input for a real part of a respective delay line tap output signal or a second phase modification unit input for an imaginary part of the respective delay line tap output signal and a first phase modification unit output for the real part of a phase modified output signal or a second phase modification unit output for the imaginary part of the phase modified output signal, wherein the second phase modification unit input is directly connected to the first phase modification unit output and the first phase modification input is connected to an interconnected sign inverter, which is connected to the second phase modification unit output, wherein the real part of the phase modified output signal is based on the imaginary part of the respective delay line tap output signal and the imaginary part of the phase modified output signal is based on a sign-inverted real part of the respective delay line tap output signal; or wherein the first modification unit input is connected to an interconnected sign inverter, which is connected to the first phase modification unit output, and the second phase modification unit input is connected to an interconnected sign inverter, which is connected to the second phase modification unit output, wherein the real part of the phase modified output signal is based on a sign-inverted real part of the respective delay line tap output signal and the imaginary part of the phase modified output signal is based on a sign-inverted imaginary part of the respective delay line tap output signals; or wherein the first modification unit input is directly connected to the second phase modification unit output and the second phase modification input is connected to an interconnected sign inverter, which is connected to the first phase modification unit output, wherein the imaginary part of the phase modified output signal is based on the real part of the respective delay line tap output signal and the real part of the phase modified output signal is based on a sign-inverted imaginary part of the respective delay line tap output signal.