RDL ACM-3 Synchronous AM Noise Measurement / Amplitude Component Monitor

The RDL ACM-3 Amplitude Component Monitor is a bench and rack tool for broadcast engineers who need to see and hear the incidental amplitude modulation riding on an FM carrier. It recovers the AM component from the RF signal, displays its level on a front-panel meter, and demodulates it to clean audio so a technician can track down the source of synchronous AM noise in a transmitter or exciter. A front-panel oscilloscope jack lets you put the recovered waveform on a scope for a closer look.

All signal connections are on BNC jacks: RF in, scope out, and a line-level audio output at +4 dBu from a 100 ohm source. The front-panel display reads from -20 dB down to -69 dB, while the scope jack extends the usable range from -10 dB to -90 dB. The unit runs from an included 18 Vac external supply and lives in a compact half-rack-depth chassis for the transmitter shelf.