Comtech EF Data CDM-425, Installation And Operation Manual

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CDM-425 Advanced Satellite Modem
Revision 0
Front Panel Operation 6–74 MN-CDM-425
6.2.2 SELECT: Test Menu Branch
TEST: Mode BERT (

)
CnC-APC-Monitor Uncorrected-BER
Use the
◄ ►
arrow keys to select a test parameter. Press ENTER .
6.2.2.1 SELECT: TEST

Mode
Modem Test Mode = Normal (

)
(NORM,Tx-CW,Tx-1/0,IF
↓
,RF
↓
,DIG
↓
,I/O
↓
)
Use the
▲▼ arrow keys to select
Normal modem operation. Press ENTER . Otherwise, select a
Test Mode from the parameters shown in the parentheses. Valid selections are:
Setting Function
NORM
(Normal) This clears any test modes or loopbacks, and places the unit back into an
operational state.
Tx-CW
(Transmit CW) Use this test mode to force the modulator to transmit a pure carrier
(unmodulated).
Tx-Alt-1/0
(Tx-1/0)
(Transmit an alternating 1,0,1,0 pattern) Use this test mode to check the carrier
suppression of the Modulator This mode forces the modulator to transmit a carrier modulated
with an alternating 1,0,1,0 pattern, at the currently selected symbol rate; this causes two
discrete spectral lines to appear, spaced at ± half the symbol rate, about the carrier
frequency.
IF-LOOP ( IF
↓
)
(IF Loopback) Use this test mode to invoke an internal IF loop. This is a particularly useful
feature, as it permits you to perform a quick diagnostic test without having to disturb external
cabling. Furthermore, all of the receive configuration parameters are temporarily changed to
match those of the transmit side. All previous values are restored once Normal is again
selected. See Figure 5-3. Starting with Firmware Ver. 1.1.1, IF Loopback now works correctly
when Carrier-in-Carrier is enabled.