A digital sine-cosine frequency synthesizer that is not an integral power of 2 and its synthesizing method

Abstract

The invention discloses a non-integral power of 2 digital sine and cosine frequency synthesizer and a non-integral power of 2 digital sine and cosine frequency synthesis method. The method includes the step that firstly, the table volume of a waveform memory is calculated; secondly, a phase accumulator carries out accumulation under the conditions of 'full length', 'half length', '1 / 4 length' and '1 / 8 length', wherein the accumulation numerical value in each time of accumulation is K; thirdly, T is made equal to 0, 1, 2 and 3 respectively through a quadrant accumulator; fourthly, synthesized sine and cosine signals are read from the waveform memory according to a numerical value accumulation result of the phase accumulator and the quadrant accumulator; fifthly, the basic address length of the waveform memory is Fs / DF. According to the non-integral power of 2 digital sine and cosine frequency synthesizer and the non-integral power of 2 digital sine and cosine frequency synthesis method, it is only required that master clock frequency equals an integral number of times the step value of output frequency, frequency errors do not exist, and waveform amplitude errors are only affected by the bit width of numerical values but not affected by the bit width interception of phase figures; because the number of phases on a phase circumference does not need to be the integral power of 2, the redundancy of the phase figures and the volume of a lookup table are reduced, the flexibility of the output frequency of the direct digital frequency synthesizer is improved, and the application range of the digital frequency synthesizer is broadened.

Description

Technical field [0001] The invention belongs to the technical field of digital frequency synthesis, and particularly relates to a digital sine-cosine frequency synthesizer that is not an integral power of 2 and a synthesis method thereof. Background technique [0002] Direct digital frequency synthesizer technology is a new frequency synthesis method. Compared with traditional analog frequency synthesizers, direct digital frequency synthesizers have the advantages of low cost, low power consumption, high resolution, and fast conversion time. A key technology for the realization of all-digital communication equipment systems. [0003] The current mature direct digital frequency synthesizer technology is mainly composed of two parts: the phase accumulator and the waveform memory. Driven by the working clock, the phase accumulator linearly accumulates the frequency control word, and outputs the phase word to look up the waveform memory. Address, so that it outputs a waveform signal w...

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Problems solved by technology

[0012] The present invention provides a non-integer power of 2 digital sine-cosine frequency synthesizer and its synthesis method, aiming to solve the problem that the digital frequency synthesizer provided in the prior art only works when the working frequency and output frequency are multiples of the integral power of 2 The relationship can only be divisible, otherwise the calculated frequency word will have errors, and the problem that the waveform memory takes up a lot of resources

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