User's Manual

Table Of Contents

ITCR Wayside User’s Manual

5/16/2013 11

7. Set the VSA to the center frequency of the channel and set it to demodulate the

8 ksym/second π/4-DQPSK emission and measure the error frequency which is

referenced to the VSA center frequency.

To adjust the master crystal reference oscillator parameters:

1. First, check the factory default setting for the crystal reference parameter by

typing

cal

2. Note the value for “xo” in the cal factors table that is displayed.

3. At the XtermW command line, type:

cal,set,xo,xx

where xx is some value close to the original factory set value.

4. Use trial and error to determine the set point for the xo value to achieve the

desired carrier frequency accuracy.

To reset the XO tuning parameter to the factory setting:

Power cycle the radio.

5.4 Measure and Adjust Output Power

Caution: Avoid unnecessary adjustments. Exercise caution when setting

DDS level (ddslevel) or other power output controls as damage to the

radio can occur if they are set too high.

The wayside radio is rated for 30W PEP and is preset to this level at the factory. If

additional tuning is required, use an appropriate method to measure PEP for a π/4-

DQPSK signal. The CCDF function on the VSA is recommended for peak power

measurement. Slowly increase/decrease ddslevel level from its nominal set point, as

determined by issuing the command ‘cal’.

To measure and adjust output power:

1. At the XtermW command line, begin transmitting a π/4-DQPSK signal by

typing: