SAMSUNG Proprietary-Contents may change without notice
6-4
Circuit Description
FM RECEIVE AUDIO PATH
De-Emphasis Circuit
This part features -6dB/oct filter to reduce signal
loss and noise in Rx path.
Expandor
The expandor features 1:2 level increaser to reduce
signal loss and noise in Rx path. The zero crossing
level of the compressor is ±2.9 kHz/dev, attack time
is 3 mS, and release time is 13.5 mS.
6-1-6 TX WBD, ST, and SAT
The WBD and ST are generated by the MSM but the
SAT is transponded by the MSM. The modulation
level of TX WBD and ST is ±8kHz/dev, and SAT is
±2kHz/dev.
6-1-7 ALERT TONE GERNERATION
A buzzer is a component which converts signals to
audio alert tones. The internal buzzer generator in
the MSM will generate PWM signal which will
drive transistors(Q251) to generate the tones. The
volume of the alert tone is controlled by the width
of PWM and the different periods.
