schaltungsanordnung to implement a unsymmetrischen input signal in a pair of symmetrical flows with equal amplitude and opposite polarity

摘要

PURPOSE:To prevent the offset of an output DC current by a base current by constituting a gain control circuit without using a differential amplifier in a signal converting circuit that converts a signal-end input signal into a differential output signal. CONSTITUTION:When signal current is is supplied from the signal current source, the electric current flowing through diode 6 changes to (I0-i1). At this time, base current (IB+iB) flows the bases of transistors 9 and 18, so that the current flowing through diode 7 is (I0-i1+iS-IB-iB), that flowing through diode 19 will be (I0-i1+iS). Therefore, the emitter current of transistor 9 is (I0-i1+is+IB+iB) and its collector current, i.e. the current flowing through diode 10 is (I0-i1+iS). Further, differential signal currents (I0-1/2is) and (I0+1/2is) flow through diodes 6 and 10 respectively.