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KX-TCD725AXM
6.3.
RF MODULE
BLOCK DIAGRAM RF MODULE
ANT1
ANT2
PAON
3.8V
TXDA
CHP
Loop
filter
SYRI
SYEN
SYDA
SYCL
RXDSG
RXDA
S&H
RSSI
6.3.1.
RF MODULE (SEE BLOCK DIAGRAM Fig.22)
The RF Module consists of two main components: the PMB6610 transceiver and the PMB6818 power amp.
In the transceiver the 10.368MHz clock signal SYCL is multiplied to around 1.9GHz using PLL (Phase Locked Loop) control.
The TXDA signal is used to control the modulation of this frequency to 1.87GHz to 1.93GHz.
Received signals are demodulated, filtered and sent to the BBIC via the RXDA line.
The RSSI (Radio Signal Strength Indicator) signal enables the implementation of diversity switching whereby two antennae can
be mounted in different orientations and their signals compared. The one with better reception can be selected by the BBIC
using the ANT1 and ANT2 lines.
VCC
VCC1
voltage
VCC
regulator
VCC1
x2
VCO
TX Part
PD
:N/A
32/33
:R
PLL &
control logic
Demodulator
VCC2
PMB6610
voltage
regulator
DECT transceiver
RXON
Low IF
band pass
filter
RX Part
Fig. 22
24
Diversity
Switching
PAON
PMB6818
Power amp.
Printed
balun
DRON
Printed
Printed
balun
RF1
RF2
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