DOWNLOAD Panasonic KX-PRS110RUW / KX-PRS120RUW / KX-PRSA10RUW Service Manual ↓ Size: 5.58 MB | Pages: 83 in PDF or view online for FREE

9

Base Unit consists of the following ICs as shown in Block Diagram (Base Unit) (P.8).

• DECT BBIC (Base Band IC): IC501

- 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 code 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
- PLL Oscillator
- Detector 
- Compress/Expander
- First Mixer
- All interfaces (ex: QSPI FLASH MEMORY, EEPROM, Analog Front End, etc.)
- Integrated 1.9GHz PA for DECT

• EEPROM: IC611

- Temporary operating parameters (for RF, etc.)

• FLASH MEMORY: IC601 (for KX-PRS120 only)

- Voice Prompt (TAM) D/L Area
- ICM/OGM Recording Area

• Additionally,

- Power Supply Circuit (+3.0 V, +2.4 V, +1.8 V output)
- Crystal Circuit (10.368 MHz)
- Charge Circuit
- Telephone Line Interface Circuit

• QSPI FLASH MEMORY IC502

- Main Program D/L Area

10

(BBIC, Flash Memory, EERROM) is a digital speech/signal processing system that implements all the functions of
speechcompression, record and playback, and memory management required in a digital telephone answering machine.The
BBIC system is fully controlled by a host processor. The host processor provides activation and control of all that functionsas
follows.

• Voice Message Recording/Play back

The BBIC system uses a proprietary speech compression technique to record and store voice message in Flash Memory.An
error correction algorithm is used to enable playback of these messages from the Flash Memory.

• DTMF Generator

When the DTMF data from the handset is received, the DTMF signal is output.

• Synthesized Voice (Pre-recorded message)

The BBIC implements synthesized Voice, utilizing the built in speech detector and a Flash Memory, which stored the vocabulary.

• Caller ID demodulation

The BBIC implements monitor and demodulate the FSK/DTMF signals that provide CID information from the Central Office.

• Digital Switching

The voice signal from telephone line is transmitted to the handset or the voice signal from the handset is transmitted to
theTelephone line, etc. They are determined by the signal path route operation of voice signal.

• Block Interface Circuit

RF part, Key scan, Telephone line.

Following information data is stored.

• Voice signal

ex: Pre-recorded Greeting message, Incoming message

Following information data is stored.

• Settings

ex: message numbers, ID code, Flash Time, Tone/Pulse

RF part

ADPCM

Analog
Front
End

&
  
Multi-
plexer

TEL
Line
Interface

Digital
Speech
Processor

Caller ID
Modem

Digital TAM  System

Flash Memory  IC601

 Host CPU

DECT RF system
 TDMA/TDD
 Mod/Demod
 PA/LNA

ADPCM

Keys/ Charge

EEPROM IC611

*1

*1

*1

*1 for KX-PRS120 only

11

The power is supplied to the DECT BBIC, QSPI FLASH MEMORY, FLASH MEMORY, EEPROM and Charge Contact from AC
Adaptor (+5.5 V) as shown in Fig.101. The power supply is as follows;

• DECT BBIC (IC501): 

DC Jack (+5.5 V) 

 IC302  IC501

DC Jack (+5.5 V) 

 IC302  Q302  IC501

DC Jack (+5.5 V) 

 IC302  Q301  IC501

• EEPROM (IC611): 

DC Jack (+5.5 V) 

 IC302  IC501 IC611

• FLASH MEMORY (IC601) (for KX-PRS120 only): 

DC Jack (+5.5 V) 

 IC302 IC501 IC601

• Charge Contact (CHARGE+): 

DC Jack (+5.5 V) 

 R371  R372  D362 CHARGE+

• QSPI FLASH MEMORY (IC502): 

DC Jack (+5.5 V) 

 IC302  IC501  IC502 

<Fig.101>

AC Adaptor 

* for KX-PRS120 only

DCP

IC302

Q302

IC501 

IC502

IC601*

IC611

+5.5 V 

1.8 V 

3.0 V 

3.0 V 

Q301

2.4 V 

CHARGE+

D362

R372

R371

DC

Jack

3.0 V 

DCM

1

2

3

On

DC

S

1.8 V

Reset

(IC501(RSTN))

Off

12

• Bell signal detection
• Clip signal detection
• ON/OFF hook circuit

In the standby mode, Q141 is open to cut the DC loop current and decrease the ring load.
When ring voltage appears at the L1T (A) and L1R (B) leads (when the telephone rings), the AC ring voltage is transferred as
follows;

• B 

 P101  C106  R106  R107  IC501 (CID INp) 

• A 

 C105  R105  R108  IC501 (CID INn)

In the standby mode, Q104 is open, and connected as to cut the DC loop current and to cut the voice signal. The unit is
consequently in an on-hook condition. 
When IC501 detects a ring signal or press the TALK Key onto the handset, Q142 turns on and then Q141 turns on, thus
providing an off-hook condition (DC current flows through the circuit) and the following signal flow makes the loop current.

• B 

 P101 D101  Q141  Q161  R163  D101  A

• Audio Circuits and DTMF tone signal circuits.

Base Unit and Handset mainly consist of RF Module and DECT BBIC. 
Base Unit and Handset transmit/receive voice signal and data signal through the antenna on carrier frequency.

*Refer to Signal Route (P.15).

The voice signal input from the TEL LINE interface goes to DECT BBIC (IC501) as shown in Block Diagram (Base Unit) (P.8)
The voice signal passes through the analog part of IC501 where it is amplified and converted to a digital audio stream signal.
The burst switch controller processes this stream performing encryption and scrambling, adding the various other fields to
produce the GAP (Generic Access Profile) standard DECT frame, assigning to a time slot and channel etc.
In IC501, the carrier frequency is changing, and frequency modulated RF signal is generated.In IC501,RF signal is amplified,
and radiated from antenna. Handset detects the voice signal or data signal in the circuit same as the following explanation of
Receiver Block.

The signal of 1900 MHz band (1881.792 MHz ~ 1897.344 MHz) which is input from antenna is input to IC501 as shown in Block
Diagram (Base Unit) (P.8).
In IC501, the signal of 1900 MHz band is downconverted to 864 kHz signal and demodulated, as GAP (Generic Access Profile)
standard DECT frames. It passes through the decoding section burst switch controller where it separates out the frame
information and performs de-encryption and de-scrambling as required. It then goes to the DSP section where it is turned back
into analog audio. This is amplified by the analog front end, and goes to the TEL LINE Interface.

During pulse dialling the hookswitch (Q141, Q142) is used to generate the pulses using the HOOK control signal, which is set
high during pulses. To force the line impedance low during the “pause” intervals between dial pulses, the PULSE_DIAL signal

turns on Q144.