Mitsubishi TRIUM ASTRAL, Service Manual, Page: 16 / 33

Level 3 Service Manual
GALAXY ASTRAL GEO GEO WAP
Mitsubishi Electric Telecom Europe SA Version E
ZA le Piquet, 35370 Etrelles Date: 04/00
Phone: +33 2 99 75 71 00
Fax: + 33 2 99 75 71 47
15/29
3.5 Transmission.
3.5.1 Transmission Block Diagram.
3.5.2 Description of Transmission Block Diagram.
The direct and phase shifted signals are then fed to I and Q modulators inside the IC600. I and Q data
components are fed into the IC600. The output from the two modulators is summed and fed out of
pin 11. The GMSK signal leaves the modulator of IC600, and is amplified also inside IC600.
E-GSM Band (880-915MHz).
A phase locked loop is created around the TXVCO IC700. The output is fed into IC600 and converted
to 270 MHz (135MHz on DCS) by mixing with RFVCO at 1150-1185 MHz (1575 – 1650 MHz DCS).
This 270 MHz signal is compared with the 270MHz signal from the modulators, and the error signal is
used to control the TXVCO. Note that the error signal on TP700 will have a DC component to control
frequency, and an AC component at approx 270 kHz to control phase changes. Then the signal is
filtered, amplified by TR702, and further filtered before to input to the power amplifier (IC702).From
the PA, the output goes through coupler Z701, is switched to the TX path and is filtered by SW700.
The signal then goes up to the antenna.
DCS Band (1710-1785MHz).
A phase locked loop is created around the TXVCO IC700. The output is fed into IC600 and converted
to 135 MHz (270 MHz on GSM) by mixing with RFVCO at 1575 – 1650 MHz. This 135 MHz signal is
compared with the 135MHz signal from the modulators, and the error signal is used to control the
TXVCO. Note that the error signal on TP700 will have a DC component to control frequency, and an
AC component at approx 270 kHz to control phase changes. Then the signal is filtered, amplified by
TR712, and further filtered before to input to the power amplifier (IC702).From the PA, the output
goes through coupler Z 700, is switched to the TX path and is filtered by SW700. The signal then
goes up to the antenna.