Check Points; Measurement Of Demod Output - Furuno FELCOM 12 Service Manual

5.3 Check Points

Board name
CPU Board
(16P0148)
RF CON Board
(16P0147)

Measurement of DEMOD output

Oscilloscope Settings
• MODE :
• VOLTS/DIV : 0.5/DIV
• TIM/DIV :
Connections
CH1 ------ TP4 or TP5
CH2 ------ TP5 or TP4
GND ----- TP1 or TP2
Lissajous Figures
• When C/N in status monitor display is 40dB
(synchronized); Two poles can be recognized.
• When C/N in status monitor display is 35dB
(synchronized); Two poles can be recognized.
• When C/N in status monitor display is 28dB
(not synchronized); Two poles cannot be recognized.
Note) The synchrozination is made when the C/N is 32dB or more.
TP No. Status
TP 1
TP 2
5Vp-p
TP 3
(1200Hz)
TP 4
TP 5
TP 1
TP2
4Vp-p
TP 3
DC5V ~ 6V
TP 4
X-Y CONV
X-Y
5-5
Signal
GND
GND
TX CLK
DEMOD OUT Rx waveform, during synchronization
Rx waveform
50kHz IF
Rx waveform output
50kHz IF
Rx IF AGC Level on status monitor
AGC Level
display; 130=5V, 100=4V, 80=3V
GND
Figure 5-2 Lissajous Figures
Remarks