| 摘要 |
PURPOSE:To obtain the large output voltage even with a low level of power supply voltage by forming a transistor 2-stage cascade constitution for a multiplier constituting an FM demodulation circuit. CONSTITUTION:The input FM signal is supplied to terminals 62 and 63 and limited by transistors (TR)1-3. Then the input signal undergoes a level shift through TRs 4-7 and is supplied to the bases of TRs 28 and 29 of a multiplier 74'. The limiting signal is applied also to an astable multivibrator circuit 72. The signal which is supplied from the circuit 72 with its phase delayed by a fixed time regardless of the degree of frequency change of the input FM signal is impressed to the common base of TRs 14 and 15 of the multiplier 74' via a level shift circuit 73. The H and L levels of the output of a level shift ciucuit 71 which are supplied to the TRs 28 and 29 are set higher and lower than the H and L levels of the output signal of the circuit 73 by a prescribed level. As a result, a signal current flows to the collectors of the TRs 14 and 15 even with a low level of power supply voltage. Then the FM signal is demodulated and delivered via an output circuit 75.
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