Freedom R8100 SERIES, Руководство оператора

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4.2.3 SINAD Measurement
Select the SINAD meter and note the bar graph and digital indication in dB. You may need to adjust the
radio’s volume until the signal level is within the meter’s range. Navigate to the RF Zone and adjust the
Generator level until the reading averages 12 dB. Note the RF level required for a 12 dB SINAD and
compare to the radio’s specification. Typical values for 2 way radios range from -100 to -120 dBm.
Note: for best results set the baseband audio filters of the analyzer to achieve a bandwidth no wider
than necessary for the modulation frequency range of the radio under test. Ex: 2-way voice is typically
300 Hz to 3 kHz. This minimizes noise in the measurement and provides smoother readings
.
4.2.4 Modulation Acceptance Bandwidth
Set the radio’s volume control to 10% of its rated output. Adjust the R8100 RF output level 6 dB above
that needed for 12 dB SINAD as determined in 5.2.3 (a 6 dB increase is double the RF voltage).
Increase the deviation level until the SINAD meter returns to 12 dB. Read the deviation and compare to
the radio’s specification.
4.2.5 Receiver Sensitivity Testing (20 dB Quieting)
Place the R8100 in Monitor mode to remove input signal from the radio. In the Meter Zone select the
AC Voltmeter. Make certain the radio is un-squelched and adjust the volume control to feed noise to the
analyzer at approximately ¼ the rated audio power. Record the noise reading in dBm.
Switch the R8100 to Generate mode, Navigate to the Audio Zone and turn off all modulation. In the RF
Zone adjust the RF output level until the noise reading on the AC voltmeter is 20 dB less than the
recorded value. Refer to the radio’s service manual and determine if any adjustments or repairs are
needed.
4.2.6 Squelch Sensitivity Test
Threshold Squelch Sensitivity
Place the R8100 in Monitor mode to remove input signal from the radio. Disable the radio’s PL/DPL
squelch if provided. Carefully adjust the radio’s squelch control to the point where the receiver just
quiets and no further.
Switch the R8100 to Generate Mode, navigate to the Audio Zone and turn off all modulation. In the RF
Zone adjust the RF output level below that required to un-squelch the radio’s receiver. Gradually raise
the level until the receiver just un-squelches. This is the threshold squelch sensitivity of the radio.
Tight Squelch Sensitivity
Repeat the test after adjusting the radio’s squelch to the tight setting – this is either a maximum or pre-
determined higher setting used to reject weak noisy signals. Refer to the radio’s service manual and
determine if any adjustments or repair are needed.
PL/DPL Squelch Sensitivity
With the R8100 in Generate mode navigate to the Audio Zone. Change the Synth Format to PL or DPL
and enter the appropriate code for the radio under test in the PL or DPL Table submenu. See Table B-
3 and B-5 in Appendix B for standard codes used in PL/DPL enabled systems. Turn the Synth mode to
On and adjust the level to provide a 750 Hz deviation or that specified in the manufacturer’s
specifications.