The RDX-6 is a broadband (0.25 to 45 MHz) passive device for allowing a single transducer to be used both for transmitting and receiving sound (pulse-echo). It protects the receiver input from the high power output of a gated amplifier without loading the pulse, and also provides an efficient transfer of signal from the transducer to the receiver.

Additional features have been incorporated to allow the user to optimize signals for a unique setup :

A switch-selectable diode expander at the input of the RDX-6. This is designed to block noise that may be present at the output of the gated amplifier. It is particularly valuable when a non-gated (always on) power amplifier is used.
Two switch-selectable high power attenuators (1 and 2 dB) follow the diode expander. Use of these attenuators will improve the signal strength to the receiver if the gated amplifier does not present a low impedance to the circuit during the off time. They are required, however, when the diode expander is in use.
Eight selectable high-pass filters to the transducer. These improve recovery time for higher-frequency signals.
Adjustable damping on the receiver input. This may be effective in minimizing ringing in the transducer.