Kenwood TKR-D710 Service Manual page 62

TKR-D710
Item Condition
24. Repeat FPU Test mode
Gain adjust 1) Adjust Item: [Repeat Gain
[Analog (Analog Wide)]
Wide] Connect the Deviation Meter
to the TX ANT end via the ATT.
Deviation Meter setting
LPF: 15kHz
HPF: OFF
De-emphasis: OFF
2) Connect the SSG to the RX ANT.
SSG setting
Frequency: Desired Frequency
Output: –53dBm (501µV)
MOD: 1.0kHz
DEV: ±1.0kHz
25. Repeat FPU Test mode
Gain adjust 1) Adjust Item: [Repeat Gain
[Analog Nar- (Analog Narrow)]
row] Connect the Deviation Meter
to the TX ANT end via the ATT.
Deviation Meter setting
LPF: 15kHz
HPF: OFF
De-emphasis: OFF
2) Connect the SSG to the RX ANT.
SSG setting
Frequency: Desired Frequency
Output: –53dBm (501µV)
MOD: 1.0kHz
DEV: ±1.0kHz
Confi rmation and Alignment of Set-up to
Prevent Receiver Desensitization
1. Confi rmation of Duplexer alignment
The duplexer allows the Repeater to simultaneously transmit
and receive. To accomplish this, in the programmed receive fre-
quency, the transmit frequency must be notched or suppressed
by 75dB or more. Additionally, on the programmed transmit fre-
quency, the receive frequency must be notched or suppressed
by 75dB or more. The following figures are examples of Du-
plexer alignment using a spectrum analyzer.
Ref –10dBm
Atten 5dB
# Peak
Log
10dB/
V1 V2
V3 FC
AA
TX
#Res BW 30kHz VBW 30kHz
62
ADJUSTMENT
Measurement
Test-
Unit
equipment
Deviation Rear
meter
Oscilloscope
SSG
RX
Span 20MHz
Sweep 50ms (401 pts)
Adjustment
Terminal Unit Parts
TX ANT PC 1.0kHz Deviation
ADJ
RX ANT
2. Confi rmation of Repeater Desensitization
The following fi gure is a Test set-up for Repeater Desensiti-
zation.
After this Test set-up is completed, confirm the Repeater
Desensitization as mentioned below.
1) Disable the repeater mode.
2) Adjust the level of the RF generator until 12dB SINAD is
reached.
3) Increase the output of the RF generator by 1dB. (This in-
creases the SINAD.)
4) Enable the repeater mode.
5) Read the SINAD level. It should not drop below 12dB
SINAD. If the SINAD is less then 12dB, check the tightness
of the connectors and the tuning of duplexer.
Duplexer
Repeater
Specifi cations / Remarks
Method
±0.1kHz
Press [Apply] button to store
the adjustment value.
Attenuated
port
50Ω
dummy
RF signal
generator