Signals similar to data seem to come out of the Data Out (DO) terminal, even when no signal is received. Why is this?

Only noise is heard at the frequency where there is no transmissions. Noise will be output from the AF when the communication distance is extremely large or no signal is transmitted. The output from DO is produced after the AF output signals are compared in the slicer circuit. This is why signal similar to data can be output, if random AF noise signal is fed to the comparator.

To balance performance and cost, the receiver does not include a mute circuit which can remove noise occurring when no signal is input. The mute circuit can be easily designed using RSSI signal. For further information please contact Circuit Design, Inc.