Handset Section - Sony SPP-SS950 Service Manual

5-2. HANDSET SECTION

• Make the set in Test mode (see page 11)
1. Checking RX I&Q Output Level
Setting:
oscilloscope
level meter
+ +
– –
SG
Procedure:
1. Place the handset in the Continuous Receive mode (1CH, LNA,
AGC ON).
2. Set the SSG frequency to the frequency on 1CH + 300 kHz,
and the RF output level to –95 dBm.
3. Measure the output lvel of RXIN, RXIP, RXQN, and RXQP
with a level meter. At this time, confirm with an oscilloscope
that a sine wave of 300 kHz is output.
4. confirm that the measured output level is –23.3 to –20.9 dBV.
If IC502 was replaced (there is no ID data), the output level
is –28.3 to –25.9 dBV.
5. Also, execute steps 1 through 4 for the channels 2 – 20.
* for the frequency on each channel, see page 7.
2. Checking TX Center Frequency
Setting:
• short: TP555 ↔ TP553
frequency counter
+
–
Procedure:
1. Short TP555 and TP553 (GND) on the MAIN board in the base
unit.
2. Place the handset in the Continuous Transmit mode (1CH, High
power).
3. Measure the ANT OUT frequency of the RF module in the hand-
set using a frequency counter.
4. Confirm that the measured freuquency is 903.600 MHz ±
27 kHz.
5. Also, execute steps 1 through 4 for the channels 2 – 20.
TP520: RXIP
TP521: RXIN
TP522: RXQP
TP523: RXQP
TP553: GND
ANTENNA TERMINAL
ANTENNA TERMINAL
3. Checking TX output
Setting:
peak power meter
+
–
Procedure:
1. Place the handset in the Continuous Transmit mode (1CH, High
power).
2. Measure the ANT OUT output of the RF module in the handset
using a peak power meter.
3. Confirm that the measured output is 29 mW (MIN 17.4 mW).
4. Also, execute steps 1 through 4 for the channels 2 – 20.
– 13 –
ANTENNA TERMINAL