Variable rate interpolation with numerically controlled oscillator

摘要

A numerically controlled oscillator includes a phase accumulator that outputs a phase word and a clock that periodically outputs a clock signal in accordance with a delay interval. The phase accumulator outputs a new phase word in response to receiving the clock signal. A clock controller calculates a timing drift and adjusts the delay interval to reduce the timing drift. A method includes receiving a plurality of frequency control words, calculating a delay interval, accumulating the frequency control words in accordance with the delay interval to generate a phase word, converting the phase word to a waveform, calculating a timing drift, and adjusting the delay interval to reduce the timing drift.

主权项

1. A numerically controlled oscillator comprising:
a phase accumulator configured to output a phase word; a clock configured to periodically output a variable clock signal in accordance with a delay interval, wherein the phase accumulator is configured to output a new phase word in response to receiving the clock signal; and a clock controller programmed to calculate a timing drift from a ratio of an output sample rate to an input sample rate and adjust a length of the delay interval of the variable clock signal to reduce the calculated timing drift, wherein the clock controller is programmed to adjust the length of the delay interval of the variable clock signal to a rate calculated from the calculated timing drift.