User Manual
SECTION 1: THEORY OF OPERATION
298994.DOC Page 10
input determines the VCO frequency. The voltage is generated by the phase detector output (PD/O) of
U2, which drives a loop filter consisting of R19, C16, C17, and C47. The filter integrates the pulses,
which normally appear on PDOUT into a smooth DC control signal for the VCO. The output of VCO1 is
attenuated by module AT2, resulting in improved VCO stability.
Amplifier U8 amplifies the signal and applies it to a splitter (U3). One output of U3 is connected to a
switch (U1). U1 is enabled by signal TX when the transmitter is enabled. The other output of the splitter
is connected through AT1 and provides feedback to U2.
Power Amplifier
The transmit injection signal from the RF injection section is applied to the high-powered linear amplifier
(U1) one (1) watt amplifier. The signal is then routed to the final power amplifier boosting the output
signal to 40 watts. The transmitter output power is controlled with R3. R3 controls the output voltage of
an adjustable regulator (U3). The signal KEY* enables the regulator. The output of the amplifier is routed
to transmit antenna port ANT (via SW1).