| 摘要 |
PURPOSE:To attain the frequency modulation and demodulation with one circuit, by providing a switch means for the base of transistors(TR) of differential constituted and switching the state being whether astable or monostable, in an emitter coupling type multivibrator circuit. CONSTITUTION:TRs Q11-Q21 and a capacitor C constitute an emitter coupling type multivibrator and TRs Q18, Q19 form a differential type current switching circuit. TRs Q5-Q8 constitute a switch means which switches the multivibrator into an astable or a monostable type. At modulation, a control voltage applied to control input terminals 15 and 16 goes to L and H respectively and TRs Q11 Q20 are operated as a voltage estable multivibrator together with a feedback circuit consisting of TRs Q6-Q7, and TRs Q9-Q10. At demodulation, the control voltage to the terminals 15, 16 are inverted and TRs Q11-Q21 are operated as a monostable multivibrator taking the base of the TRs Q5, Q6 as a trigger input terminal. |
