Circuit Operation (Base Unit); Outline - Panasonic KX-TCD450 Series Service Manual

KX-TCD450RUM / KX-A145RUM / KX-TCD450RUT / KX-A145RUT

20 CIRCUIT OPERATION (BASE UNIT)

20.1. Outline

Base Unit consists of the following ICs as shown in BLOCK DIAGRAM (BASE UNIT) (P.57).
· DECT BBIC (Base Band IC): IC2
− − − − Handling all the audio, signal and data processing needed in a DECT base unit
− − − − Controlling the DECT specific physical layer and radio section (Burst Module Controller section)
− − − − ADPCM codec filter for speech encoding and speech decoding (DSP section)
− − − − Echo-cancellation and Echo-suppression (DSP section)
− − − − Any tones (tone, sidetone, ringing tone, etc.) generation (DSP section)
− − − − DTMF receiver (DSP section)
− − − − Clock Generation for RF Module
− − − − ADC, DAC, timer, and power control circuitry
− − − − All interfaces (ex: RF module, EEPROM, LED, Analog Front End, etc.)
· RF Module: IC3
− − − − PLL Oscillator
− − − − Detector
− − − − Compress/Expander
− − − − First/Second Mixer
− − − − Amplifier for transmission and reception
· EEPROM: IC1
− − − − Temporary operating parameters (for RF, etc.)
· Flash Memory: IC4
− − − − Program Code
· Additionally,
− − − − Power Supply Circuit (+4.0V, +2.65V output)
− − − − Crystal Circuit (10.368MHz)
− − − − Charge Circuit
− − − − Telephone Line Interface Circuit
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