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SAMSUNG Proprietary-Contents may change without notice
6-7
STH-N375
Circuit Description & Circuit Diagrams
AMPS (Limiting and Discrimination)
The downconverted signal from the output of F300 enters to the limiter and discriminator of U301. For the
better suppression of the unwanted interferers, discrete LC filter is used in the limiter section. The signal
through the limiter goes into the discriminator (or quadrature detector) of U301 with incorporation of the
quadrature tank circuit (LC resonator) placed outside of U301, and thus the audio signal comes out from
the pin 16 of U301. This demodulated signal is connected to U101.
TDMA (Rx AGC and 1, Q Demodulator)
The downconverted signal from the output of F300 enters to the Rx AGC and 1, Q demodulator of U301.
The Rx AGC has the performance of 80-dB dynamic range, 10 dB NF, and -85dBm IIP3. In the process of 1,
Q demodulation, 450 kHz local signal, made by dividing 14.4 MHz reference clock, is used.