The DVPD-01 Dual Video Presence Detector senses the presence of NTSC video or sync and activates a DPDT relay if the signal is lost. Two video signals may be monitored with a single unit (loss of one signal will not affect the monitoring of the other signal). The DVPD-01 uses special, high noise immunity, detection circuitry; it will not falsely activate on noise produced by off-air demodulators or microwave receivers with no input signal.
Video presence detector with relay contacts and TTL outputs, which respond to the presence of video or sync;
DC voltage proportional to the peak of the video signal normalized to 5 VDC;
DC voltage proportional to the amplitude of the sync signal normalized to 4 VDC (40 IEEE units* of sync gives 4 VDC).
A new option (DVPD-02) measures the color burst amplitude and generates a linear DC signal normalized to 4 VDC (40 IEEE units* of burst gives 4 VDC). The circuit responds linearly from 10 to 40 IEEE units* thus giving information about the luminance to chrominance ratio.
The second option (DVPD-03) makes the DVPD respond to the presence of a VIT signal and then becomes a VIT presence detector with the same relay contacts and TTL outputs and DC analog outputs as listed above. This option is useful to allow remote selective switching functions. It is also useful in satellite-fed systems using receivers equipped with an internal sync generator that is switched on during RF failures, thus giving a false indication of the presence of video (example: Bell ExpressVu 3100 Receiver). The option can be programmed to select a specific VIT line from 10 to 21. A set of jumpers, located inside the unit, is used to select either normal full field operation or VIT operation. Since the DVPD is a dual-channel detector, the option can be set to work on one or both channels independently.
When used with Off-Air Receivers, the DVPD is very selective and immune to high noise levels as well as to adjacent-channel interference in satellite receivers.
Use the DVPD for:
The DVPD monitors unattended video signals at TV, cable, production or satellite facilities and will alert you of loss of signal or automatically switch to back-up equipment. The DVPD will provide digital (status) inputs that are compatible with the Davicom remote monitoring & control unit.
Museums, theme parks, public transportation facilities or distance learning
The DVPD will monitor unattended video feeds, such as information kiosks or automated classroom sessions fed over a network, and will automatically activate an alarm or switch to a back-up source if the signal is lost.