Determining Synthesiser Lock Ranges - Tait TB8100 User Manual

Determining Synthesiser Lock Ranges

TB8100 Service Kit User's Manual
To measure signal levels
1. Select Diagnose > Reciter > Signal Level.
2. In the Center frequency box, specify the middle frequency of the band
you want to test. This can be any frequency within the receiver's
range.
3. In the Channel spacing box, select a value from the drop-down list. This
specifies the size of the step from one frequency to the next. If this
corresponds to the channel spacing, you will measure signal levels of the
different channels in the band.
4. Click Start Test. The base station sets the receiver to a frequency, measures
the RSSI, increments the frequency by the value in the Channel spacing
box, measures its RSSI and so on for 101 steps below and above the center
frequency you specified.
When the test is complete, the graph displays the measured RSSI values and
annotates the x-axis with the correct frequency values.
You can test the reciter's synthesisers to determine the range of frequencies that
the receiver and the exciter can operate on. Use these tests to check that the
reciter is calibrated correctly for the channels that it will operate on.
The Clock source box indicates whether the reference frequency is internal
or external to the base station.
The bottom group of boxes with LEDs indicate the lock status of various parts
of the reciter in its current operation.
To test the exciter or receiver lock range
1. Select Diagnose > Reciter > Synthesisers.
2. Click Start Test in the exciter or receiver row.
The exciter or receiver checks all the channel frequencies in the band that
the base station is type-approved to operate in.
3. In the Lower Frequency and Upper Frequency boxes, view the results
of the test. These values report the range within which the synthesiser is able
to lock onto the specified frequency.
Note: The reported ranges are conservative. In fact, the base station
will be able to transmit and receive outside the range, but with
reduced transmit output and receive sensitivity.
4. Click Stop Test. The exciter and receiver frequencies revert to what they
were when you started the test.
switching
Reciter Tests 153