Technical data

S:\hp11807a\OPT001\USRGUIDE\BOOK\chapters\descrptn.fb

Chapter 4, Test, Parameter, and Pass/Fail Limit Descriptions

TEST_05. TX Audio Frequency Response

This test compares the audio frequency response of your transmitter to a 6 dB/

octave pre-emphasis curve from 0.5 kHz to 2.5 kHz. Variation from that pre-

emphasis curve is measured separately for frequencies <0.5 kHz and >2.7 kHz.

An additional roll-off is allowed from 2.3 kHz to 2.7 kHz, and from 2.7 kHz to 3

kHz in equipment operating in the 896 MHz to 940 MHz range. Audio

connections from the radio to the test set are required for this test.

The test results indicate the flatness of the audio output as frequency is varied.

Audio frequency response is measured in “dB error” from the 6 dB/octave pre-

emphasis slope.

If your radio has Continuous Digital-Controlled Squelch System (CDCSS) or

Continuous Tone-Controlled Squelch System (CTCSS), the added signal can

cause this test to fail. In this case, disable the CDCSS circuitry.

Pass/Fail Limits Used

Pass/Fail Limit 20, TX Audio Response Delta From 6 dB/oct

Pass/Fail Limit 21, TX Audio Frequency Response Roll <0.5 kHz

Pass/Fail Limit 22, TX Audio Frequency Response Roll >2.3 kHz for 896-940M

Pass/Fail Limit 23, TX Audio Response Roll >2.5 kHz

Pass/Fail Limit 24, TX Audio Frequency Response Roll >2.7 kHz for 896-940M

Test Parameters Used

Parameter 2, RT Full Rated System Deviation

Parameters 21-23, TX Audio Freq Response Start, Step, and Stop Frequency

Testing Conditions Defined by the Software

• Audio frequency response is measured at 20% of the rated system deviation and the

reference is taken at 1 kHz rate.

• The rms detector is used when the 20% reference is set.