Abell A720T, Service Manual

Page: 28 / 56

A720T (VHF) Service Manual V1.0
28/56
(
level 1
frequency point
2 adjustment
)
(
level 9
frequency point
2 adjustment
)
automatically detect
data
After debugging,
click the
confirmation to save
detection data
6.audio frequency
deviation
broadband
adjustment
Adjust channel
CH:2(middle
port)
AG:1KHz/120
mv
frequency
deviation filter
LPF:15KHz
HPF:50KHz
power
meter
frequency
deviation
meter
oscilloscop
e
Audio
generator
Antenna
Termina
l
JK101
Mic
socket
A720T
programming
software
frequency
deviation wide
band middle
port adjustment
Enter audio
frequency deviation
adjustment
After Changing sub
audio
deviation
adjustment, click
confirmation to save
debugging data
Wide band
frequency
deviation
：
4.2KHz±0.2
KHz
7.audio frequency
deviation narrow
band adjustment
A720T
programming
software
frequency
deviation
narrow band
RF:middle port
adjustment
narrow band
frequency
deviation
：
2.2KHz±0.2
KHz
1. transmit
digital 4FSK bit
error rate
adjustment
Test channels:
CH1 CH2 CH3
CH4 CH5 3920
measuring
equipment
Antenn
a
terminal
JK101
JK102
Connect
comput
er
A720T
progra
mming
softwar
e
Digital send path I amplitude path Q
adjustment:this
adjustment needs
AEROFLEX
3920. click digital
adjustment item to adjust path Q
digital frequency deviation, via +/- to
adjust digital frequency deviation
within 1.9KHZ~2KHZ, then via path I
to adjust bit error rate , use path I to
adjust digital bit error rate mainly and
adjust frequency deviation slightly.
Use path Q to adjust digital bit error
rate and also adjust frequency
deviation slightly. When you adjust
path Q to a higher value, path I needs
to be adjust higher or lower according
to current situation. In a word, you
need to adjust both path I and path Q.
Adjust channel 1 to standard range,
then click confirm, then adjust next
channel one by one.(CH 1.2.3.4.5)
Digital
frequency
difference
1.9KHZ~2.0
KHZ
Bib
error
rate
：
< 5%