12
AUDIO LEVELS ALIGNMENT
This section describes how to determine and set the audio levels.
The procedures below can be used to approximate the response of the internal microphone. These
measurements must be taken within 15 seconds of powering the unit on. This is because the unit may enter
power saving mode after that time. Measurements made while the unit is in power saving mode will not be valid.
The unit ships with the power save feature enabled by default. The power save feature can be disabled via the
programming software so that it will not interfere with taking measurements.
1. A method for controlling transmitter modulation is required for accurate measurements in the TX mode. A
small speaker held in place near the microphone by a rubber band can serve this purpose in most cases. Use
a sine-wave generator to inject a 1000 Hz tone into the speaker. Adjust the output of the sine wave generator
so that the transmitter produces 60% of rated modulation while PTT is pressed.
2. Leaving the generator output set to the same level, install the SM-1 microphone with the same set up as
above. Press PTT and using a communications monitor, observe the modulation level.
3. In the programming software, adjust MIC Out to obtain 60% modulation.
4. Spkr In should be set to 1980 mvpp.
5. MIC In and Spk Out should be set to 1920 mvpp.
