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KX-TG2257BXS
12.3. Signal Flowchart in the Whole System
Reception
CN1 of the base unit is connected to the TEL line, and the signal is input through the bridge diode D4. While talking the relay
(Q4) is turned ON and amplified at the amplifiers Q50, then led to DSP (IC201). DSP generates ADPCM signal. The ADPCM
signal is input to RFIC (IC101) of RF UNIT. RFIC outputs FSK modulated RF signal. The RF signal is passed through filter
(FL101) to be transmitted from the antenna. As for the handset, RF signal from the antenna is input to RFIC passing through
filter (FL101) then input to DSP (IC201). DSP performs ADPCM decoding to convert the signal into the voice signal, then it is
output to the speaker.
Transmission
The voice signal input from the microphone is led to DSP (IC201). The DSP generates ADPCM signal. As well as the reception,
it is converted into the RF signal by RFIC (IC101). Passing through filter (FL101), it is transmitted from the antenna. As for the
base unit, RF signal from the antenna is input to RFIC (IC101) passing through filter (FL101) then input to DSP (IC201). DSP
performs ADPCM decoding to convert the signal into the voice signal. The voice signal is amplified at the TX amplifier (Q1), then
output to the TEL line (CN1) through the relay (Q4) and bridge (D4).
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