FM limiter for SECAM decoder - is fitted to fourth and fifth transistors coupled to differential amplifier inputs and by own base to fixed bias

摘要

The FM limiter, for SECAM decoders, has fourth (4) and fifth (5) transistors coupled by their emitters to the bases of the transistors in the differential pair and connected by their own bases to the ends of a two resistor decoupling circuit (14, 15). The decoupling circuit is supplied with a fixed bias (17) at its centre point. (The input signal is applied over a capacitor to the base of the fourth transistor and the output is taken via the collector of one of the differential transistors). The advantage lies in few connections to the IC, little external circuity, and the lowest number of adjustments and the greatest number of functions.