Read Panasonic KX-TCD951GB / KX-TCD955GC Service Manual online
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KX-TCD951GB/KX-TCD955GC
1. THE BASE-BAND SECTION (SEE BLOCK DIAGRAM Fig. 25)
1.1 INTRODUCTION
The base-band section consists of a base-band integrated circuit (BBIC), a Flash PROM, an EEPROM, an LCD
Display, a Microphone, an Earpiece, and power supply/battery management circuits.
1.2 THE BASE-BAND INTEGRATED CIRCUIT (BBIC)
The National SC14404 BBIC (IC1) is a CMOS device designed to handle all the audio, signal and data processing
needed in a DECT handset. It contains two microprocessors - one general purpose - while the other “burst mode
controller” takes care of DECT specific physical layer and radio section control.
The BBIC also contains the ADPCM transcoders, a low power 14 bit codec (ADC/DAC), various other ADC’s, DAC’s
and timers, a UART for data communication with RF unit, a gaussian filter for the DECT GFSK modulation method,
clock and data recovery circuits, a clock oscillator circuit, a battery management circuit, and a pair of gain
controllable amplifiers for the microphone and earpiece. On some handset models, the Flash ROM will also be
contained within the BBIC.
Fig.26
+3V +3V
Fitted to some models only
Circuit Diagram
CIRCUIT OPERATION (HANDSET)
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