Banner, Birch, McKie & Beckett
Logarithmic amplifier
 An input signal voltage applied to a signal input terminal is converted to a current by a differential amplifier, a voltage-to-current conversion resistor and an NPN type bipolar transistor. An input-impedance determining resistor is connected between the noninverting input terminal of the differential amplifier and ground. An NPN type bipolar transistor, whose collector is shunted to its base, has its collector connected to a constant current source and its emitter connected to a constant voltage source. The base of the NPN transistor is connected to the base of an NPN type bipolar transistor. The emitter of the transistor is connected to the collector of the transistor. A signal output terminal is connected to a connection point of the collector of the transistor and the emitter of the transistor. 
Kabushiki Kaisha Toshiba
G
G06G
inventional
Shuji
Watanabe