Frequency agile digital radio receiver

Apparatus for use in a radio receiver chain, where the radio receiver chain includes an analog-to-digital converter for converting the analog RF signal to a digital RF signal at a sample rate of fADC to generate a serial stream of RF samples, the apparatus comprising:

• a serial-to-parallel converter configured to convert the serial stream of RF samples into M parallel streams of RF samples, each stream having a sampling rate of fADC/M, where M is a positive integer greater than 1;
• signal processing circuitry configured to translate the M parallel streams of RF samples to M parallel streams of intermediate frequency (IF) samples centered about an IF of fADC/4, the M parallel streams of IF samples including a first set of even IF samples and a second set of odd IF samples and to demodulate the M parallel streams of IF samples by applying a first set of associated coefficients to the first set of even IF samples to produce a first set of even demodulated samples and applying a second set of associated coefficients to the second set of odd IF samples to produce a second set of odd demodulated samples;
• and
• a filter configured to filter the even demodulated samples using a first set of filter coefficients of a digital filter and the odd demodulated samples using a second set of filter coefficients of the digital filter to produce a complex baseband signal.

A frequency-agile radio receiver system, comprising:

• an analog input for receiving an analog radio frequency (RF) signal;
• an analog-to-digital converter for converting the analog RF signal to a digital RF signal at a sample rate of fADC to generate a serial stream of RF samples;
• a serial-to-parallel converter configured to convert the serial stream of RF samples into M parallel streams of RF samples, each stream having a sampling rate of fADC/M, where M is a positive integer greater than 1;
• signal processing circuitry configured to translate the M parallel streams of RF samples to M parallel streams of intermediate frequency (IF) samples centered about an IF of fADC/4, the M parallel streams of IF samples including a first set of even IF samples and a second set of odd IF samples and to demodulate the M parallel streams of IF samples by applying a first set of associated coefficients to the first set of even IF samples to produce a first set of even demodulated samples and applying a second set of associated coefficients to the second set of odd IF samples to produce a second set of odd demodulated samples;
• and
• a filter configured to filter the even demodulated samples using a first set of filter coefficients of a digital filter and the odd demodulated samples using a second set of filter coefficients of the digital filter to produce a complex baseband signal.