Trigger circuit with transistors as emitter resistors - uses inverting differential amplifier to increase precision of opposing phases

摘要

The trigger circuit has the differential amplifier that acts as inverter designed so as to produce two signals having exactly opposite phases. Transistors (T5, T6) are used for the differential amplifier's emitter resistors. The emitters of these transistors are connected to a shared emitter resistor (R4). The bases of the transistors are connected respectively to the non-inverted undelayed input signal and to the inverted undelayed input signal. Two emitter followers (T7, T8) are connected to the differential amplifier and their bases are connected respectively to the non-inverted delayed input signal and to the inverted delayed input signal. The current may be used in a frequency demodulator for a magnetic tape recorder.