دارات تكبير التردد المتوسط للصوت if .. كتاب التلفزيون الملون والعادي

18- 4 IF amplifier circuits:

They are one or more amplification stages, similar to the IF amplifier circuit but with a narrower bandwidth and are valves in older devices such as valves

- PCL82- PCF80
6DT6 - PCL86 - ECC82

Or transistor circuits BF126 - BF195. Figure (7-18) and (8-18) show a transistor audio midrange amplifier circuit. As for modern devices, one integrated circuit IC performs several functions in the sound stage, as it works as an intermediate frequency amplifier and limiter - a frequency modulation detector and an audio frequency amplifier. Among these circuits - TA7164P TBA800 - TBA120 and others. Figure (9-18) shows the use of an integrated circuit in the Seronix device.

The intermediate frequency (55) MHz resonant circuit may be of the crystal type. The mid-frequency amplification circuit amplifies the MHz FM signal with its two sidebands to the level necessary to operate the limiter stage or the next stage. The output amplitude of the amplifier is approx.
(2 - 5 volts)