DIFFERENTIAL CIRCUIT AND FM DEMODULATION CIRCUIT USING THE SAME

摘要

PROBLEM TO BE SOLVED: To secure symmetry of current waveforms by applying input signals to the control terminals of 3rd and 4th transistors TR and then outputting these signals via a path where the mutual connecting point between each of both ends of 1st and 4th TRs is connected to a DC power supply and also via a path where the mutual connecting point between each of both ends of the 2nd and 3rd TRs is connected the DC power supply. SOLUTION: When a positive voltage and a negative voltage are applied to the bases of TR Q15 and Q16 respectively by an AC signal ein , a total current of (α+γ)+(β-γ)=(α+β) obtained from the collector current (α+γ) of a TR Q1 and the collector current (β-γ) of the TR Q15 flows to a resistor R1 . Current in the R1 is not affected by the currentγthat flows in the emitter-base capacitor CEB of a TR Q2 , and current in a resistor R2 is not affected by the currentγthat flows in the emitter-base capacitor CEB of the TR Q1 .