摘要

电能表作为用电量的测量工具广泛的应用于各种场合。在电能表校表系统中,需要的最基本的输入信号源是高精度双路正弦信号源,并要求可对其频率、相位、幅值进行调节,来对电能表进行校准。

基于单片机的程控信号源设计，运用数字调相、数字调幅和数字调频等技术，要求实现相位、幅度、频率的高精度程控调节。本文设计了一种利用锁相环频率合成技术和数字波形合成技术组成的程控低频正弦波信号发生器，并给出了调幅、调频、调相的实用电路，频率调节通过改变8253计数器的分频系数来实现；相位调节由51单片机预置计数器的计数初值来完成，幅度的调整通过改变DAC1210II的参考电压来实现，使频率分辨率达0.01Hz,相位调节精度达0.1°，并介绍电路中的主要芯的功能及使用。输出正弦波频率和幅值的精度高，稳定性好，失真度低，电路简单、可靠、便于程控。



关键词：数字合成信号源；程控；调幅；调频；移相；

-Abstract

Meter consumption as the size of the measurement tool is widely used in various occasions. In single-phase power meter verify system, the most basic needs of the input signal is the source of two-way high-precision sine signal source, and may request its frequency, phase, amplitude in a certain step to adjust to the imitate of the actual electricity load with a right meter calibration.

Design of the programmable signal supply controlled source，which based on the MCU，including digital phase adjustment，distal amplitude adjustment，digital frequency adjustment etc．The system should achieve high quality digital adjustment of phase, amplitude and frequency. This paper describes the use of a PLL frequency synthesizer technology, and digital wave form synthesis technology consisting of program-controlled low-frequency sine wave signal issued devices, and applies the amplitude， frequency， phase of practical circuit. Frequency can be adjusted through a change in the 8253 counter-frequ