Signal Flowchart In The Radio Parts - Panasonic KX-TG4021LAT Service Manual

KX-TG4021LAT/KX-TG4022LAT/KX-TG4023LAT/KX-TGA403LAT
4.1.3.

Signal Flowchart in the Radio Parts

Reception
A voice signal from TEL line is encoded to digital data "TXDATA" by BBIC (IC501) in a base unit.
Then TXDATA goes to RF PART and it's modulated to 1.9 GHz. The RF signal is amplified and fed to a selected antenna.
As for a handset RF, RF signal is received in one antenna.
BBIC down-converts to 864 kHz IF signal from RX signal and demodulates it to digital data "RXDATA".
BBIC (IC1) converts RXDATA into a voice signal and outputs it to speaker.
Transmission
A voice signal from microphone is encoded to digital data "TXDATA" by BBIC (IC1) in a handset.
Then TXDATA goes to RF PART, and it's modulated to 1.9 GHz. The RF signal is amplified and fed to a antenna.
As for a base unit RF, RF signal is received in two antennas.
BBIC (IC501) compares RF signal levels and selects the antenna to be used. Then BBIC down-converts to 864 kHz IF signal
from RX signal in the selected antenna, and demodulates it to digital data "RXDATA".
BBIC (IC501) converts RXDATA into a voice signal and outputs it to TEL line.
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