FPGA (Field Programmable Gate Array)-based high-precision signal generator with phase self correcting capability

Abstract

The invention discloses an FPGA (Field Programmable Gate Array)-based high-precision signal generator with the phase self correcting capability. The signal generator at least comprises a crystal oscillator circuit, an FPGA chip, a D / A (Digital / Analog) convertor, a low-pass filter and an A / D convertor, wherein the FPGA chip at least comprises a phase accumulator, a phase adder, a waveform lookup table, a data output control module, a data receiving control module, a phase difference detection module, a phase locked loop frequency multiplication module and an A / D conversion control module. The invention constructs the signal generator with the closed loop feedback regulation capability; the high-speed A / D convertor is used for performing A / D conversion on an output waveform signal; the A / D conversion result is directly input into the FPGA module and then is subjected to phase discrimination treatment by virtue of the phase difference detection module, so that an output waveform signal phase error is obtained; the phase adder is used for performing phase self correcting on the output waveform signal according to the phase error, thereby obtaining a high-precision phase waveform signal. According to the signal generator, problems such as simplicity and convenience in design, precision and cost are fully considered, the circuit is simple and flexible, and the signal generator is easy to expand and has practical value.

Description

technical field [0001] The present invention relates to a signal generator based on Direct Digital Frequency Synthesis (Direct Digital Frequency Synthesis, DDS or DDFS for short) technology, in particular to a FPGA-based high-precision phase self-correcting signal generator. Background technique [0002] Waveform signal generator is a kind of signal source, which is widely used in scientific research and engineering design as an excitation source. In the prior art, the DDS signal generator based on FPGA is mainly composed of phase accumulator, address accumulator, waveform look-up table, D / A converter, low-pass filter and so on. Due to the phase error caused by the software and hardware on the generated waveform signal; in order to reduce the phase error, at present, peripheral equipment is generally used to sample the output waveform signal of the low-pass filter in sections, and it is calculated by the relevant calculation formula The actual waveform signal phase is obtai...

AI Technical Summary

Problems solved by technology

However, the complexity of the peripheral equipment greatly increases the design cost of the signal generator; and the workload of the design increases, and the feedback delay of the peripheral circuit and the error caused by itself make the design complicated and difficult to operate

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