Ranging standard generator for continuous wave RADAR systems, has two loop voltage controlled oscillator whose modulated output signal deviation is controlled by Bessel nulling loop by generating bipolar DC signal

摘要

The generator has two loop voltage controlled oscillator (VCO) to maintain carrier phase at a value determined by crystal controlled oscillator. Phase locked loop (PLL) along with Amstrong phase modulator generates FM waveform to modulate the VCO. Bessel nulling loop with a phase sensitive amplitude detector, controls the frequency deviation at a specific deviation ratio by generating a bipolar DC signal. The generator having two loop voltage controlled oscillator generates FM waveform with sine wave deviation, precisely controlled so that the carrier nulls at specific known deviation ratio.