Audio ICs
Pin 6: AFC circuit
It is possible to use the pin 6 detector output DC voltage
and apply AFC. Fig. 12 shows an application example
where the BA4424N is used as the FM front end.
Even if you will not use AFC, when recovering the sub-
carrier phase-modulated composite signal (voice-multi-
plexed TV) in the next stage, match the oscillator and “S”
curve orientations in the same way as described above.
If they are reversed, the left and right channels of the re-
covered audio will be reversed.
BA1442A
349