NICAM decoder with output resampler
A NICAM audio signal re-sampler may include a non-linear interpolator configured to interpolate in a non-linear manner between sequential digital samples that are based on a stream of demodulated NICAM audio samples. A phase differential calculator may be included that compares phase information at different resolutions.
1. A NICAM audio signal re-sampler comprising:
a non-linear interpolator configured to interpolate in a non-linear manner between sequential digital samples that are based on a stream of demodulated NICAM audio samples;
a local sample clock; and
a synchronizer configured to synchronize an interpolated stream of demodulated NICAM audio samples with the local sample clock.
2. The NICAM audio signal re-sampler of claim 1 further comprising a phase comparator configured to generate a measurement of phase difference between a signal that is synchronous with the stream of demodulated NICAM audio samples and a signal that is synchronous with the local sample clock.
3. The NICAM audio signal re-sampler of claim 1 wherein the local sample clock is at a frequency of approximately 31.25 kHz.
4. The NICAM audio signal re-sampler of claim 1 wherein the local sample clock is at a frequency of approximately 32 kHz.
5. The NICAM audio signal re-sampler of claim 1 wherein the local sample clock is at a frequency of approximately 44.1 kHz.
6. The NICAM audio signal re-sampler of claim 1 wherein the local sample clock is at a frequency of approximately 46.875 kHz.
7. The NICAM audio signal re-sampler of claim 1 wherein the local sample clock is at a frequency of approximately 48 kHz.
8. The NICAM audio signal resampler of claim 1 , wherein the resampler is disposed in a digital signal processor.
9. The NICAM audio signal resampler of claim 1 , wherein the non-linear interpolator comprises a parabolic interpolator.