FREQUENCY/VOLTAGE CONVERTER

摘要

PURPOSE:To obtain a speed signal which has good controllability over the entire band by using an integration type frequency-voltage converting device for a high frequency band and using a waveform obtained by analog arithmetic processing for a low frequency band. CONSTITUTION:An A-phase and a B-phase sine wave which are 90 deg. out of phase with each other are sent from an encoder 20 and separated into a low-frequency and a high-frequency component through a low-pass filter 6 and a high-pass filter 7. The low-frequency component is converted into a rectangular wave by an A-phase compara tor 11 through an analog arithmetic circuit 8 and the B-phase wave is converted into a large-amplitude waveform by a differentiating circuit 14; and those waveforms are supplied to a multiplier 15 to obtain a speed signal with a half period. Similarly, the B-phase wave is converted by a comparator 12 into a sine wave and a speed signal with the remaining half period is obtained by a multiplier 16; and those are added together by and adder 17 to obtain a low-frequency speed signal having the full period. The high-frequency wave is converted into a high-frequency speed signal by an integration type FV converting device 9. Those low-frequency and high-frequency speed signals are added together by an adder 10 to obtain an entire-band speed signal.