Systems and methods for pre-averaged staggered convolution decimating filters

A system for implementing a multirate digital decimating filter for filtering received symbol data, the system comprising:

• a receiver for receiving symbol data;
• at least one memory for storing data and computer-executable instructions;
• at least one processor configured to access the at least one memory and further configured to execute the computer-executable instructions to:
• sample the received symbol data at a selected sample rate;
• pre-average the sampled received data to provide two samples per symbol;
• convolve the pre-averaged samples with decimated FIR aperture impulse response coefficients to produce detected output samples;
• convolve the pre-averaged samples with shifted decimated FIR aperture impulse response coefficients to produce decimated detected zero-crossing transition samples;
• and
• adjust the sample rate based at least in part on averaging the zero-crossing transition samples.

A filter for demodulating and filtering received symbol data, the filter comprising:

• at least one memory for storing data and computer-executable instructions;
• at least one processor configured to access the at least one memory and further configured to execute the computer-executable instructions to:
• sample the received symbol data at a selected sample rate;
• filter the sampled received symbol data to remove spectral replicas;
• pre-average the sampled received data to provide two samples per symbol;
• convolve the pre-averaged samples with decimated FIR aperture impulse response coefficients to produce detected output samples;
• convolve the pre-averaged samples with shifted decimated FIR aperture impulse response coefficients to produce decimated detected zero-crossing transition samples;
• and
• adjust the sample rate based at least in part on averaging the zero-crossing transition samples.