Frequency doubler for TV receiver - doubles horizontal sweep frequency using sawtooth generator and differential amplifier

摘要

In a TV receiver synchronisation of the vertical sweep with the horizontal sweep is achieved using a frequency doubler which doubles the horizontal sweep frequency. The horizontal sweep frequency is applied to an input terminal of a sawtooth generator having the same frequency as the applied sweep frequency. The sawtooth waveform output is applied to a diferential input amplifier stage to obtain a square wave with leading and trailing edges occurring where the sawtooth waveform passes through a reference voltage. The amplifier output is differentiated and the pulses are shaped to produce the required output at double the input frequency.