[SBE] DTV image freeze alarm

[a9xw at cs.com]

The output of a digital FS is ASI in HD or SD. Could be a 270 Meg ASI, 1.3 gig or 3 gig, 19.39 meg or some other data rate chosen.  The issue is, when the input quits it either freezes on the last frams or shitches to blue screen depending on where ina DTV system you are monitoring hte data stream. The issue is, the data stream does not cease, and thus no loss of signal alarm. I've decided to get a cheap $150 motion alarm that sticks on the face of a monitor. If the video on the monitor does not change during the set time, it will trigger an alarm that says I hae a freeze frame, not active video.  The broadcast version is $25k, a simple alarm company video motion detector is $150 to get a contact closure to tell an auto dialer to call for help. 8VSB is a psudo random data stream, even with no audio or video input, the encoder continues to generate a data stream, again the issue, even if the data stream has no input, the outpout does not stop, thus no loss of signal alarm. The exciter has a loss of MPEG alarm, but does not output the alarm if there is an STL loss since the STL goes through a few boxes to make Nielsen and 310M, so there is always MPEG, albiet loss of PID, etc that is upstream of the STL.  
And in the event of a power loss, the transmitter is not going to output anything but the STL rack on UPS continues to run for a while, or the 1 on 3 chance that that phase is OK and the phase 2/3 circuit is dead. So the difficulty in detecting a power loss other than look at the tower lights out the window. [vs an STL or TX failure].  Remember DTV is perfect ... perfect blue screen.  

Henry







-----Original Message-----
From: Gibson Prichard <gibson at prichard.tv>
To: sbe member discussion mail list <sbe at sbe.org>
Sent: Tue, Jun 29, 2010 8:46 pm
Subject: Re: [SBE] DTV image freeze alarm


I'm not sure I get the criteria, Henry. What sort of frame sync passes 8VSB or ASI? Frame Synchronizers are use to time video to a house standard and don't process ASI or certainly not 8VSB. If you're looking to detect frozen video from a tuner, there are numerous devices that will do that, from multi-viewers with SNMP monitoring to simple video freeze alarms with contact closures. If you want a tuner with built-in freeze-frame detection (and presumably loss of carrier detection), someone like Sencore comes to mind. 
FM Systems makes a card that will detect frozen video and switch to another feed, as well give an alarm contact of freeze status. Presumably something you already have can alert you. 
 
Best of luck. 
 
Gibson 
Nashville 
 
On 6/29/2010 1:45 PM, a9xw at cs.com wrote: 

> Anyone know of a product that will detect frozen video feed from 8VSB > or ASI output of a frame sync? [vs a still frame]. 

> I need to alarm a distant (unviewed locally) video loss to dial "help > I've failed and can't move my lips." 

> Henry Ruhwiedel 

> 

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