ADCP-61-813 • Issue 2 • February 2005
Page 11
© 2005, ADC Telecommunications, Inc.
5.1.1
Calibration
Since normal operation is with the A channel as primary, calibration need only be performed on
the A input channel. Calibration cannot be performed on channel B. Switching the unit to B will
place the unit in a manual mode of operation and disable all switching capability.
RF connectors must be terminated before calibration is performed. The unit should be placed
into the configuration in which it is to be used before attempting calibration.
Use the following steps to calibrate the RDS-AS:
1. Confirm that a nominal signal level to channel A is present.
2. Select PORT (1 or 2) with threshold switch.
3. Flip MODE SELECT switch to CALIBRATION.
Figure 13. RDS-AS Front Panel
5.1.2
Setting The Threshold
After calibration, lock onto the port 1 with the THRESHOLD switch, then set the desired
threshold level with the threshold toggle switch.
The threshold set in this mode of operation will be the level below which the calibrated signal
must drop before switching from the primary to standby receiver/amplifier. For example, if
receiver A is calibrated with a 40 dBmV power level and the threshold is set for 3 dB down, the
RDS-AS will switch to receiver B whenever the “A” signal level falls below 40 – 3 = 37 dBmV.
Repeat the above procedures for Port 2.
5.2
Operation
Threshold adjustment, calibration, and selection of the input channel can be performed on both
ports. Use the threshold switch to select a port for modification, up for port 1, down for port 2.
Note:
If an “H” or an “L” appears in the display, the signal level is either too high or too
low. Verify that an acceptable signal level is present before continuing. (See
Note:
A “Guard Band” of 0.5 dB is added to all threshold settings to prevent premature
switching; i.e., when setting = 3 dB, 3.5 dB is used as the switching point.
Note:
To maintain accuracy after an extreme change in input signal level or operating
temperature, unit may require “Re-calibration” at the new condition.
12212-A
