Audio Response: Motorola Mitrek

This is the audio response as seen on pin 11 (DET OUT) of the control cable connector. This is buffered discriminator audio with no de-emphasis applied. Note the gradual rolloff that begins above 1.0kHz; also note that the scale of the chart is only +1 to -1dB, so the response is essentially flat through the range of interest.

The output at pin 11 is about 1.8 volts peak-to-peak for a 2200Hz tone deviated 3kHz.

This is the transmitter response of the Mitrek, with audio injected to the pin 1 (MIC HIGH) of the control cable connector. The frequency response is quite limited, with a definite flattening above 2.0kHz. The pre-emphasis between 1200Hz and 2200Hz is 4.5dB.

With the IDC (deviation) control on the channel element set per the Motorola manual, it takes 52.4mV RMS of audio to generate 3kHz deviation on a 2200Hz tone.