JPS5647130A - Synchronous oscillator - Google Patents

Abstract

PURPOSE:To obtain a stable oscillation output by forming a delay feedback loop that feeds the output of an amplifier back to the input via a delay line. CONSTITUTION:Voltage control oscillator 7 generates a continuous wave of a random frequency by operating an external control signal. This has pulse width set adequately by pulse-width controller 9 and is modulated into a pulse modulated wave by the pulse modulator. This pulse modulated wave controls the oscillation frequency of the following delay feedback loop. The delay feedback loop consists of coupler 10, amplifier 11 and delay line 12 and amplifier 11 is so set that the loop gain will be one. The transfer function of the delay feedback loop has periodic poles with integral multiples of the reciprocal of the delay time of the delay line. The delay feedback loop oscillates with the most closest cylinder to the carrier frequency of input modulated pulses. Then, the delay time of delay line 12 is prolonged and the intervals between poles of the transfer functions of the delay period loop are shortened, so that the degree of freedom of oscillation frequency selection can be increased.