User's Manual

85894_M&R_TA7650C_A 2-6
prosessed in the DSP on the mainboard, and the I/Q signals to the modulator are modified
accordingly.
Synthesizer
The VCO is operating at 2 times the output frequency. Q4 is the oscillator transistor and the
frequency is controlled by varicaps D1and D2. The VCO have a separate regulated supply to
get as low noise as possible on the output signal. The signal is then split up in three parts. On
signal is going to the divider IC1 which supplies the modulator LO signal. The VCO signal is
also supplied directly to the demodulator which operates on the double frequency. A part of
the LO signal is also fed to the synthesizer IC3. The synthesizer is controlled from the main
board via the SPI bus.
Reference input is taken from the system clock located on the main board.
2.6 Software module
The Software module contains all necessary software to make the TA-7650C transmitter unit
functional.
2.7 PSU-7002 Power supply Unit
The PSU converts an AC input voltage between 105VAC and 250VAC to a 28V regulated
DC voltage to support the 7000 series transmitters.
The maximum load is 280VA.
If both the AC and DC power supply connection is made to the PSU, it will automatically
switch to the DC backup supply in case the main AC supply fails.
2.8 Remote Data Interface
The data on the RS-232/RS-485 bus is transferred both ways with a data rate of 1200 b/s,
using 9 bit data format, and 1 stop bit.
The data on the LAN connection uses SNMP protocol.