Method for eliminating frequency deviation of numerically controlled oscillator

Abstract

The invention provides a method for eliminating the frequency deviation of a numerically controlled oscillator. The method comprises the following steps of: calculating common factors of three frequencies according to an intermediate frequency and a local frequency used in the numerically controlled oscillator and an output frequency of a system; selecting a value of a common factor from the calculated common factors, and taking the value as the minimum frequency resolution of the numerically controlled oscillator; and setting a waveform storage and a phase accumulator in the numerically controlled oscillator according to the minimum frequency resolution and the sampling frequency of the numerically controlled oscillator. By the method, the frequency deviation of the numerically controlled oscillator (NCO) can be effectively eliminated, the NCO without frequency deviation is realized, the spurious performance of the NCO is improved, the design complexity of the NCO is reduced, the resources of the system are saved, and the production cost is reduced.

Description

Technical field [0001] The present invention relates to the field of communication technology, in particular to a method for eliminating the frequency offset of a numerically controlled oscillator. Background technique [0002] At present, with the rapid development of communication technology, digital technology has been increasingly applied to various communication products. With the development of digital frequency synthesis technology, numerically controlled oscillator (NCO) has been widely used in communication systems due to its high frequency resolution, short switching time, and low phase noise. [0003] In the prior art, NCO is a high-precision sine and cosine digital signal generator, which can convert an input signal of a first frequency into an output signal of a second frequency, thereby generating quadrature sine and cosine signals. Generally speaking, there are currently three implementation methods of NCO: look-up table method, real-time calculation method, and a c...

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Problems solved by technology

[0006] It can be seen from the above that in the prior art, if the NCO in actual use wants to meet the requirements of the system, it is difficult to effectively eliminate the frequency offset to achieve a completely frequency-offset-free NCO, thereby reducing the performance of the system, and also requires Occupies a lot of system resources; at the same time, because the minimum resolution of the NCO in the prior art is very small, the design complexity is also very large, thereby also increasing the corresponding production cost

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