Cisco Cisco Digital Service Access Node (DSAN) 8211 Troubleshooting Guide
Chapter 2 Hardware Installation
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4032301 Rev A
Reverse Path Upstream Signal (Port 1)
The reverse path is unity gain (0 dB). The DSAN provides no internal adjustment for
levels and tilt for the upstream signal. Although no reverse path setup is required,
you should verify the proper level upstream of the DSAN.
levels and tilt for the upstream signal. Although no reverse path setup is required,
you should verify the proper level upstream of the DSAN.
Output Path Downstream Signal (Port 3)
The signals generated by the DSAN exit the unit at the Mixed Services output port
(Port 3). The nominal DSAN analog output level is + 20 dBmV (±1.0 dB). The
nominal DSAN analog spectrum output flatness is 3 dB peak-to-valley. The digital
portion of the DSAN output spectrum should be configured to be 6 dB down from
the analog portion (nominally +14 dBmV).
(Port 3). The nominal DSAN analog output level is + 20 dBmV (±1.0 dB). The
nominal DSAN analog spectrum output flatness is 3 dB peak-to-valley. The digital
portion of the DSAN output spectrum should be configured to be 6 dB down from
the analog portion (nominally +14 dBmV).
The DSAN analog output signal levels are fixed and are not a function of the input
power level to the DSAN. The operator can adjust the level of the digital tier signals
(>564 MHz) at the Mixed Services output port (Port 3), if needed, by changing the
FWD IN PAD value.
power level to the DSAN. The operator can adjust the level of the digital tier signals
(>564 MHz) at the Mixed Services output port (Port 3), if needed, by changing the
FWD IN PAD value.
Note: Due to its RF output level, the next component in the network following the
DSAN must be an amplifier, preferably a high gain dual with a low input signal
requirement.
DSAN must be an amplifier, preferably a high gain dual with a low input signal
requirement.
Complete the following steps to verify and set the signal levels for the output of the
DSAN unit.
1 Connect the test probe to the Mixed Services output port (Port 3) test point (FWD
DSAN unit.
1 Connect the test probe to the Mixed Services output port (Port 3) test point (FWD
OUT -20dB TP).
2 Monitor the output levels of all active channels between 585 MHz and the upper
frequency limit of the plant.
a Note the highest and lowest signal levels over that frequency range.
b Add together the highest and lowest signal levels noted above, and then
a Note the highest and lowest signal levels over that frequency range.
b Add together the highest and lowest signal levels noted above, and then
divide the result by 2.
c Use the resulting average value as the reference digital channel signal level
for step 4 below.
3 Measure and note the output signal level of Channel 2 (55.25 MHz) at the Mixed
Services output port (Port 3) test point (FWD OUT -20dB TP). Use this value as
the reference analog channel signal value for step 4 below.
the reference analog channel signal value for step 4 below.
4 Confirm that the reference analog channel signal level found above is 6 dB
greater than the reference digital channel signal level found above. If necessary,
adjust the FWD IN PAD value to achieve 6 dB difference between the reference
analog and digital signal levels.
adjust the FWD IN PAD value to achieve 6 dB difference between the reference
analog and digital signal levels.
5 If any problems persist, see Verifying Operation (on page 25) for instructions on
using the diagnostic interface for further investigation.