Direct Digital Frequency Synthesizer Based on Improved Cordic Algorithm

Abstract

The present invention discloses a direct digital frequency synthesizer based on an improved CORDIC algorithm, including: a phase accumulator and a phase amplitude converter, wherein the phase accumulator is 32 bits wide, and 19 bits wide after the output is truncated; and the phase amplitude converter consists of a lookup table ROM, a multiplier, a super-four rotation module and a block selection module, wherein addressing is performed by the lookup table ROM using the 15-9th bit of a phase word to perform table lookup on the lookup table ROM so as to obtain a rough value of rotation, the rough value is input into the super-four rotation module after being operated by the multiplier, a 9-bit phase word is also input into the super-four rotation module at the same time, rotation calculation is performed on the rough value by the super-four rotation module using the super-four CORDIC algorithm, and a corresponding mirroring operation or turnover operation is performed on data output by the super-four rotation module by the block selection module according to the 18-16th bit finally, thereby obtaining a final output result. The synthesizer disclosed by the present invention has the advantages of lower noise, short conversion time, high SFDR, and few consumption of resources of hardware circuits.

Description

technical field [0001] The invention relates to a direct digital frequency synthesizer, in particular to a direct digital frequency synthesizer based on an improved CORDIC algorithm. Background technique [0002] Direct digital frequency synthesizer is referred to as DDS for short, which is a new type of frequency synthesis equipment that has only been developed in recent years. This kind of equipment relies on the rapid development of integrated circuit technology. Modern integrated circuit technology is constantly improving according to the prediction of Moore's law. Direct digital frequency synthesizers are also receiving more and more attention in this environment. This kind of frequency synthesis has higher resolution, faster conversion time and lower noise than the traditional frequency synthesis equipment before the equipment, so it is widely used in many electronic systems. [0003] The phase accumulator and the phase-to-magnitude converter form the digital circuit ...

AI Technical Summary

Problems solved by technology

[0007] (1) The output delay is long;

[0008] (2) It needs to go through multiple rotation calculations;

[0009] (3) Consuming more hardware resources

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