CL-D26X
HANDSET
Rechargable
BatteryQ10Buzzer
Charge PinBuzzerQ12
Volumn
Charge andControl
Quick ChargeBuzzerBack Light
ControlCharge Detect & ControlSignal
D3
Volumn Control6MHz
Xtal
U2
SPEAKERU1Q2,Q3KEYPAD
MCU
MCU Tx DATA
Helical
Q7Q8,Q9Antenna
VCO
Transmit Audio
MICReceivedRF Transmitter
U1
DataDual
PLL
10.24MHzDuplexer
OSCVCO
2nd mixer1st mixer
FM
Detect
Recovered
AudioU1Q1
RF Front
RF ReceiverEnd
455kHz10.7MHz
BPF2BPF1
Figure 23 HANDSET BLOCK DIAGRAM
2. Transmit Portion
1. Receiver Portion
The acoustic signal from the network is fed to FM modulator
An incoming RF signal from the base unit (46.670 -
through the compressor. The variable resistor, VR1 in
46.970 MHz) which is fed to ANTENNA is supplied to 1st
handset is used to prevent over modulation.The digital
MIXER through Rx filter (receiver RF Amplifier) and
control signal from the microcomputer U2 is then fed to
B.P.F. (Band Pass Filter) then Mixed with Rx LOCAL
Tx VCO for making FM modulation signal.
VCO signal (35.915 - 36.275 MHz).
The Tx VCO is formed by Q7 in Cloppits oscillator
The receiving frequency signal of CH1is passed to the RF
format.The frequency sterring is controlled by the variable
front end which is comprised of low noise FET Q1 and the
capacitor VD1.
tank coil T1. The amplified signal is supplied to 1st
The Tx VCO RF signal output is then buffered and
MIXER of the RF combo IC U1. 1st IF signal which is the
amplified by Q8 and Q9.
difference (46.610 - 35.915 = 10.695 MHz) is fed to 2nd
This signal is then fed to HELICAL ANTENNA through
MIXER through 10.695 MHz 1st IF FILTER. The 2nd IF
49.670 - 49.990 MHz Tx band pass filter (DPX1).
signal is obtained by mixing the 10.695 MHz IF signal with
2Ond local signal 10.240 MHz. The 2nd IF, 455 kHz, is then
3. Antenna and Ground System
fed to the IF amplifier via the 455 kHz filter. The 455 kHz
signal is then demodulated via quadrature demodulation.
The recovered signal is splitted into voice audio and FSKBase UnitHandset
data detection. The audio signal through low pass filterAntennaBuilt-in Rod AntennaBuilt-in Helical Antenna
and expander is amplified by the operational amplifier in(Unbalanced)(Unbalanced)
the RF system IC and audio amplifier of U1. (pin 15, pinGroundInner ChassisInner Chassis
16, pin 17, pin 18, pin 19, pin 20 of U1 and the connecting
resistor and capacitor components)4. Frequency Synthesis Portion
The detected FSK signal from compander is fed toPLL(RF SYstem IC) has dual phase lock loop which
microcomputer U2 through comparator. ( pin 24 and pinsynthesis all 10 Tx and 10 1st local oscillator frequencies
23 of U1)from the 10.240 MHz crystal frequency. The selection of
the channel access is controlled by microcomputer U2 via
serial link CLK, DATA and EN of U1. The control signal
will then control the built-in programmable divider to
enable channel selection and MCA capability.
N 23 N |
ACEC
SHARP
