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Chapter 4, Test, Parameter, and Pass/Fail Limit Descriptions
TEST_11. RX Hum and Noise
TEST_11. RX Hum and Noise
This test measures the receiver’s hum and noise ratio (a ratio of the output signal
power to the residual output power in the absence of modulation) in decibels.
Hum and noise is measured at unsquelched and squelched settings.
Audio connections from the radio to the test set are required for this test.
Pass/Fail Limits Used
Pass/Fail Limit 8, RX CT/CDCSS FM Hum and Noise
Pass/Fail Limit 11, RX Hum and Noise Squelched
Pass/Fail Limit 12, RX Hum and Noise Unsquelched
Test Parameters Used
Parameter 2, RT Full Rated System Deviation
Parameter 11, RX Maximum Audio Power
Parameter 14, RX Squelch Control
Parameter 16, RX Standard RF Input Level
Parameter 17, RX Tolerance for Setting Volume
Testing Conditions Defined by the Software
• The receiver’s unsquelched FM hum and noise is measured at 60% of rated system
deviation ( Parameter 2, RT Full Rated System Deviation) at a 1 kHz rate.
• If the radio has a squelch control, the hum and noise at the squelched position is also
measured.