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Part 3.2 : Testing the Receiver
Using a suitable high frequency probe measure the RF levels at the relevant
points shown in fig 3.1 and compare your measurements with those shown in the
diagram. If there are any major differences between the readings taken and those
indicated then further investigation of that particular point will be required. It will
also be necessary to ensure that all the following power supplies and signals are
present which control this part of the receiver circuit:-
V_G_LNA
1.
( 2.85V supply which powers the GSM LNA and TX/RX switching
diode pack: D400). See figure 3.4.
V_P_LNA
2.
( 2.85V supply which powers the PCN LNA and TX/RX switching
diode pack: D401). See figure 3.5.
RX_ON2
3.
( Control signal which supplies the GSM LNA, the RX demodulator
and internal buffer's). See figure 3.6.
2V85_RF2
4.
( A 2.85V power supply derived from MicroMoe IC204, which
supplies V_G_LNA and V_P_LNA)
GSM_LNA
5.
( Control signal from Superchip pin 29 which switches V_G-LNA).
See figure 3.7.
PCN_LNA
6.
( Control signal from Superchip pin 30 which switches V_G_LNA).
See figure 3.8.
TCXO (X200)
7.
- 13 Mhz clock on Test Point 413, see figure 4.9.
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