Performing In-Band Power Meter User Calibration - Motorola ASTRO 25 GTR 8000 Manual

5 From the menu, select Service → Test And Measurement Screen.
The Test And Measurement Screen dialog box appears.
6 If the base radio is not already in service mode, perform the follows substeps, otherwise go to
step 7.
a Click Change to Service Mode.
b At the confirmation screen, click OK.
The base radio halts activity in the current mode and switches operation to the requested
mode.
c Re-open the Test And Measurement Screen, as described in
7 If measuring the base radio transmit signal, connect the Tx connector at the rear of the base
radio to the T/R (Transmit/Receive) port on the front of the service monitor. (Both are N-type RF
connectors.)
8 If measuring the base radio receive signal, using a splitter, connect the RX-A and RX-B ports at
the rear of the base radio to the GEN port on the front of the service monitor.
9 Press the green power button on the front of the service monitor.
10 If the Test Screen is not displayed (see
3900 Series Service Monitor) on page
monitor.
11 Locate the specifications for the GTR 8000 Base Radio configuration being tested. See
8000 Base Radio Specifications on page
12 If no further testing is needed, place the base radio in Normal Mode, as follows:
a Click Change to Normal Mode.
b At the confirmation screen, click OK.
The base radio halts activity in the current mode and switches operation to the requested
mode.
5.12.2

Performing In-band Power Meter User Calibration

When and where to use:
The Aeroflex 3900 series High Performance Data (HPD) service monitor has two forms of power
measurement:
• Broadband is similar to the working of an in-line wattmeter.
• In-band is performed after the RF signal is down converted to baseband by a Digital Signal
Processor (DSP).
If the HPD service monitor runs continuously, it requires periodic calibration. Re-calibration is required
only if the User Calibration Threshold is exceeded. The service monitor displays a flag at the bottom
indicating to re-calibrate to maintain the accuracy indicated in the User Calibration Threshold.
For an HPD signal, only the in-band power meter is available. The in-band power measurement
accuracy without a user calibration is ±1 dB. User calibration improves the accuracy at a specific
Chapter 5: GTR 8000 Base Radio Optimization
Figure 82: HPD Service Monitor Test Screen (Aeroflex
198), press the Test button on the front of the service
40.
MN003286A01-E
step 5.
GTR
199