论文部分内容阅读
图(a)所示电路中使用若干廉价的运放便构成了平方律频率—电压转换器(简称为平方律FVC)。其特点是输出电压与输入脉冲频率的平方成正比,精度优于±0.15％。有关诸点的波形如图(b)所示。第一级IC_1(LM331)为频率—电流变换器(FIC),其输出脉冲电流的幅度为Io,占空比为To/Tin,其中To=1.1RoCo,Tin=1/fin。第二级IC_2A将IC_1的输出电流信号Io变为电压信号V_1,其幅度为-Vo(约为-10V)。将V_1经C_1隔直便得到了Vo。V_2的正信号分量的幅度为VoTofin。可见其幅度与输入信号的频
The circuit shown in Figure (a) uses a number of inexpensive op amps to create a square-law frequency-to-voltage converter (referred to as square-law FVC for short). Its characteristic is the output voltage is proportional to the square of the input pulse frequency, accuracy better than ± 0.15%. About the points of the waveform shown in Figure (b) below. The first stage of IC_1 (LM331) is a frequency-current converter (FIC). Its output pulse current has an amplitude of Io and a duty cycle of To / Tin, where To = 1.1RoCo and Tin = 1 / fin. The second stage IC_2A changes the output current signal Io of IC_1 into a voltage signal V_1 with an amplitude of -Vo (about -10V). Vo will be obtained by isolating V_1 from C_1. The magnitude of the positive signal component of V_2 is VoTofin. Visible amplitude and frequency of the input signal