| 摘要 |
PURPOSE:To simplify the constitution of a demodulating device, by providing a voltage control oscillator which delivers synchronous detecting reference signals to demodulate the 1st and 2nd modulated signals and an automatic variable phase shifter and therefore demodulating the 1st and 2nd modulated waves through a single voltage control oscillator. CONSTITUTION:A voltage control oscillator 30 oscillates a synchronous detecting reference signal to demodulate the 1st modulated signal sent from a terminal 111 The output of oscillation is branched into two parts by a signal branching circuit 31. One of these two outputs is applied to a phase detecting circuit 29, and the other is applied to a phase detecting circuit 28 via a pi/2 phase shifter 32. At the same time, a part of the output of the oscillator 30 is applied to an automatic variable phase shifter 53 to produce a synchronous detecting reference signal to demodulates the 2nd modulated signal sent from a terminal 116. This reference signal is branched by the circuit 31 and supplied to phase detecting circuits 28 and 29 respectively. Thus a single oscillator 30 demodulates the 1st and 2nd modulated waves. This can simplify the constitution of a demodulating device. |
