– 29 –
4-2.
HANDSET SECTION
VT adjustment and TX confirmation
Set the Handset in the Radio System Test
Mode
where
the
chan-
nel
is T1
CH
and TX
is
turned
on.
(See
page
19)
1. TX VT adjustment
Setting:
Precedure:
• Connect a voltmeter to TP6 and TP30.
• Adjust L52 so that TX VT value (DC voltage) is 1.2 ± 0.05 V.
2. RX VT adjustment
Setting:
Precedure:
• Connect a voltmeter to TP5 and TP30.
• Adjust L102 so that RX VT value (DC voltage) is 3.0 ± 0.05 V.
3. TX confirmation
Setting:
Precedure:
Confirmation of TX frequency
• Measure the TX frequency with a modulation analyzer to con-
firm that it is 48.800 ± 0.001 MHz.
Confirmation of TX output
• Measure the TX output with a modulation analyzer to confirm
that it is 1.0~4.0 mW.
Confirmation of the degree of modulation
• Set the oscillator output to 1 kHz, –54.5 dBV.
• Measure the degree of modulation with a modulation analyzer to
confirm that it is 0.45~0.90 kHz DEV.
• Observe the demodulated waveform of modulation analyzer with
an oscilloscope to confirm that it is a sine wave free from distor-
tion.
Confirmation of modulation distortion factor
• Set the oscillator output to 1 kHz, –40 dBV.
• Observe the demodulated waveform of modulation analyzer with
a distortion meter to confirm that the distortion is below 2.0 %.
Confirmation of the degree of ID modulation
• Press
[6]
key to set the Handset in the Message Transmit & Re-
ceive Test mode.
• Measure the degree of modulation with a modulation analyzer
to confirm that it is 1.8~3.5 kHz DEV.
• Observe the demodulated waveform of modulation analyzer with
an oscilloscope to confirm that it is a rectangular wave.
RX adjustment
Set the Handset in the Radio System Test
Mode
where
the
chan-
nel
is T1
CH
and
RX
is
turned
on.
(See
page
19)
1. RX level adjustment
Setting:
Precedure:
• Adjust FL101 so that the RX output becomes maximum. In such
a case, measure the RX output with an audio analyzer to confirm
that it is –18~–10 dBV.
• Observe the demodulated waveform of audio analyzer with an
oscilloscope to confirm that it is a sine wave free from distor-
tion.
+
–
digital voltmeter
TP6 (TX VT)
TP30 (GND)
+
–
digital voltmeter
TP5 (RX VT)
TP30 (GND)
+
–
+
–
+
–
oscilloscope
deviation meter
Modulation analyzer
HPF: OFF
LPF: <15 kHz
DET: AVERAGE
ANTENNA TERMINAL
TP3 (RF GND)
HPF: 400 Hz
AF oscillator
TP28
TP29
SG
ANTENNA TERMINAL
TP3 (RF GND)
Frequency : 43.780 MHz
RF output
: 60 dB
µ
V EMF
Signal
: 1 kHz INT
Deviation
: FM 3 kHz DEV
+
–
+
–
oscilloscope
Audio analyzer
TP47 (RX)
TP30 (GND)
MEAS. mode : AC Level
Input range
: –20 dBV
Filter
: < 20 kHz
Summary of Contents for SPP-A400 - Cordless Telephone With Answering Machine
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