基于光敏耦合定时器的压频转换器的实现

研制了基于定时器的压频转换器, 电路主要由工作于非稳态多谐振荡器模式下的定时器LM555和两个光敏电阻构成. 由于数字存储振荡器测得的定时器输出波频率与所施加的输入电压基本呈线性比例关系, 所研制的转换器为类数字输出, 因此具有线性输入/输出关系、 体积小、 易携带和高性价比等优点. 此外, 定时器输出波可以直接与PC机、 微处理器或微控制器相连, 不需要模/数转换器就能完成对输入电压信号的进一步处理.

Development of OPTO-LDR coupled timer based voltage to frequency converter

This paper describes the development of a timer based voltage to frequency converter (VFC). Timer LM555 is used in astable multivibrator mode with two OPTO-LDRs (light dependent resistors) in the circuitry. The frequency of timer output waveform which is measured using a digital storage oscillator (DSO) is almost linearly proportional to the applied input voltage. Hence we obtain a linear relationship between the frequency of timer output waveform and the input voltage. Because of its quasi-digital output, the main advantages of this developed converter are linear input-output relationship, small size, easy portability and high cost performance. In addition, the timer output waveform can be directly interfaced with personal computer or microprocessor/microcontroller for further processing of the input voltage signal without intervening any analog-to-digital converter (ADC).