Direct digital frequency synthesis (DDS)-based signal source

Abstract

A direct digital frequency synthesis (DDS)-based signal source relates to a signal source which is based on the DDS technology. The DDS-based signal source comprises a phase-locked loop clock circuit, a key shake-removal interface circuit, a control circuit, a DDS modular circuit and other parts, wherein the DDS generates digital signal through a field programmable gate array (FPGA), the digital signal is converted into a continuous adjustable sine wave with the frequency being between 30-100Hz and the phase being between 0-360 degrees, the control circuit uses a Nios II system, so the core part of the whole system is completed on an FPGA chip. The DDS-based signal source is used for signal simulation, simulates the signal required by electronic equipment with the same characteristics as the practical environment, tests the performance of the equipment, and is used as a standard source to calibrate or compare with the common signal.

Description

Technical field: [0001] A signal source based on direct digital frequency synthesis DDS relates to a signal source based on direct digital frequency synthesis technology DDS. Background technique: [0002] Frequency synthesis technology has experienced nearly 80 years of development since it was proposed in the 1930s, and can be divided into three stages: direct frequency synthesis technology, phase-locked loop frequency synthesis technology and direct digital frequency synthesis technology. Direct frequency synthesis technology uses frequency multiplication, frequency division, and frequency mixing circuits to add, subtract, multiply, and divide one or several reference frequencies to generate the required frequency signal, and then select it through narrow-band filtering. This is the latest synthetic filtering technology, which is simple in principle and easy to implement. Its synthesis method can be divided into two types: correlation synthesis method and non-correlation...

AI Technical Summary

Problems solved by technology

Its synthesis method can be divided into two types: correlation synthesis method and non-correlation synthesis method. The frequency is provided by these frequency sources. The disadvantage is that it is difficult, complicated and costly to make multiple crystal reference frequency sources with the same frequency stability and accuracy; the correlation synthesis method only uses one crystal reference frequency source, and the various frequencies required are determined by the reference frequency Obtained after frequency division, frequency mixing, and frequency multiplication, the frequency stability and accuracy of the synthesized frequency are the same as the reference frequency

The frequency range of the direct frequency synthesizer is wide, the frequency conversion speed is fast (microsecond level), the frequency interval is small, the operation is stable and reliable, but the parasitic output is large, a large number of analog components are required, the structure is complex, the volume is large, and the cost is high

Images