DP405 Service Manual
6. Modulation and Test
6.1. Method
During the repair, if the components are changed, you need to test and adjust theh technical specification.
6.1.1. Components needed for adjustment
（1）antenna interface converter
（2）universal interface
6.1.2. PC Test Mode Modulation Method:
Tx Section
Tx Frequency
Under computer mode(frequency stability), adjust Tx frequency as reference frequency within ±100Hz.
B. Power
a.under computer mode(Tx high power)(five frequencies), adjust Tx high power as 3.5-5.0W.
b.under computer mode(Tx low power) (five frequencies), adjust Tx low power as 0.5-1.5W.
C. Battery low power indication during transmission: set power voltage as 6.5V, and under computer mode
(Tx low voltage), click Ok after digits are stable.
Rx Section
Maximum Volume
Set the RF frequency of integrated tester as center frequency, signal strength as 1mV, modulated
frequency deviation as 3.0 kHz /1.5kHz（wide/narrow band）. Under computer mode(max volume,
wide/narrow band), adjust audio power as 1.2-1.5W.
B.Squelch
a. RF signal is set to -121dBm, modulated frequency deviation to 3.0kHz/1.5kHz（narrow/wide band）.
Under computer mode (SQL on, narrow/wide band) (five frequencies), click Ok when the value is stable.
b. RF signal is set to -123dBm, modulated frequency deviation to 3.0kHz/1.5kHz（wide/narrow ban）. Under
computer mode (SQL off, narrow/wide band) (five frequencies), click Ok when the value is stable.
6.2. Radio Test
(1)Volatge used in test: 7.5V +/-0.1V room temperature
(2)Frequency range:
S760:400MHz～470MHz
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