Electronic Tracking Systems for Satellite Ground Stations

Effect of Time—Discontinuous Amplitude Modulated Signal on the Performance of an Injection Synchronized Microwave AM-to-PM Converter

“…When the input signal is a time discontinuous (square wave) amplitude modulated one, it can be represented mathematically as (3) where £, 2 /2, WS and ()i are respectively the power, angular frequency and the phase of the input signal, m is the step modulation depth and x(t) represents the modulating square wave of period T. which is much greater than the synchronizing signal period. When the frequency of x(t) is low, each step transition can be regarded as an independent event.…”

“…Because of the circuit simplicity and an excellent amplitude limiting characteristics, synchronized oscillators are widely used as carrier phase estimators, coherent amplifiers and filters and AM -to-PM converters. In some practical situations, such as in burst-synchronization systems, pulsed radars and 'electronic beam-squint' satellite tracking systems in its satellite-acquisition phase of operation [3][4][5], the input signal is a time-discontinuous amplitude modulated (TDAM) one which may also"be referred as rectangular wave modulated (RWM) or discrete-data-modulated (DDM) AM signal. To the knowledge of the author, although in [6) an effort has been made to study the performance of a first order phase-locked loop in presence of a TDAM signal, the problem of direct synchronization ofSSMW oscillator in this situation is not reported.…”