Monroe Electronics’ Model 625A RF/IF Sensor provides automatic 2x1 RF/IF switching controlled by the loss of video modulated RF carrier.
The 625A’s sense input circuit monitors horizontal sync pulses on the video modulated RF carrier and automatically switches to the secondary input upon a decrease or loss. The relay remains in this state with the secondary input connected to the output, until the sync pulses on the video modulated RF carrier return. This causes the primary input to switch back to the output connection.
The 625A’s sensing input requires an external bandpass filter and pad for multiple channel feed conditions.