– 5–4 –
TX path is a translation loop architecture consisting of an IQ modulator, integrated high power VCO, offset mixer,
programmable divider, PFD, charge pump, and power amplifier with its control circuit.
The device consists of an In-phase and Quadrate (I/Q) modulator within a frequency translation loop designed to
perform frequency up-conversion with high output spectral purity.
Clock source is 26MHz VCTCXO external instead of XTAL function block active. VCTCXO is more stable over
extreme condition and current saving in standby mode.
■
Transceiver - - Transmitter
Base-band
section
Power
Detector
Coupler
Antenna
3-wire bus
TX IN
TX IN I/Q
+
–
PAVAPC
PA
TXVCO
900
1800/1900
PFD
UHF synthesizer
PA gain
controller
Figure 5.3. Transmitter block diagram