| 摘要 |
PURPOSE:To reduce the phase noise, by using a pair of J-K flip-flops which are triggerred by pulse width modulation signals having phases opposite to each other. CONSTITUTION:The triangular wave signal input to carrier input terminal 32 has the phase inverted by wide-band amplifier 33 having a differential output and is applied to reference terminals of two high-speed voltage comparators 34 and 35 and is compared with the modulation signal input to terminal 31. Two-phase PWM signals having the opposite phase of the carrier wave are obtained as their outputs. They are frequency-divided by J-K flip-flops 37 and 38 to obtain small-phase noise PPM signals of the half frequency of the carrier wave. Exclusive OR among them is operated by exclusive OR gate 42, thus obtaining the PPM signal, which is equal to the carrier frequency and has maximum phase shift + or -90 deg., at output terminal 46. |
