Method and digital control oscillator for sinusoidal and cosine signal generator

Abstract

The invention discloses a method for producing sine and cosine signals, which comprises the steps that: an angle sequence is generated; the generated angle is treated with phase truncation; the angle after the phase truncation is parted into a high address bit including highest two address bits and a high address bit, the highest two address bits of which are wiped off, and a low address bit; the symbols of the sine and cosine signals corresponding to the angle are calculated by the highest two address bits; the corresponding sine and cosine values are obtained by inquiring a Pi/2 sine table and a Pi/2 cosine table with the high address bit, the highest two address bits of which are wiped off; the low address bit is corresponded to a trigonometric function for being equivalent to the value of the low address bit; a finite term Tylor series expansion of the trigonometric function is utilized for obtaining the sine and cosine values of the angle by the sine and cosine values and the value of the low address bit; the sine and cosine signals of the angle are obtained by the obtained symbols and the calculated sine and cosine values. The invention also discloses a numerical control oscillator. By utilizing the method, the space occupied by storage lists can be effectively compressed under the condition that phase-truncated word length is not increased.

Description

technical field [0001] The invention relates to the technical field of digital communication, in particular to a method for generating sine and cosine signals and a numerically controlled oscillator. Background technique [0002] In the digital circuit of wireless communication, especially after the signal processing is digitalized, that is, after the signal intermediate frequency and even the radio frequency are digitalized, in order to achieve the purpose of frequency conversion in the digital domain, it is necessary to apply a digital local oscillator. In many digital circuits, the digitized sine and cosine signals (that is, the sequence of sine and cosine function values) are output as digitized local oscillator signals. [0003] The principle of generating sine and cosine signals in the prior art is as follows: figure 1 shown. The sine and cosine values ​​of each angle are stored in a read-only memory (Read Only Memory, ROM). An angle sequence is generated by the pha...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a method for generating sine and cosine signals and a digitally controlled oscillator, so as to overcome the shortcoming that the storage table takes up too much space in the prior art

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