Re: [Phys-l] Digital TV signal delay

["John Clement" <clement@hal-pc.org>]

If the boxes are the same, are they really the same?  If the serial numbers
are far apart there may have been a design change.

Beyond this are the TVs being fed from the same spigots?  In other words is
one being fed HDMI and the other one a composite signal?  There should be no
difference between S-video and composite, but HDMI or component outputs may
be different.  Is one set digital, and the other analog?  These are some of
the relevant questions that might bear on the question.

Or there is the possibility at one converter box may be defective.  I had
that problem with HD radio, and the defective box introduced a huge delay.

John M. Clement
Houston, TX

> Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu> writes:
> > You state that you had a digital cable installed. Is a digital box
> > connected to all your television sets? In Rhode Island, two services
> > come into the house simultaneously, one requires a digital decoder box
> > at each television and the other is a non-HD service that can be fed to
> > many sets using a splitter. There is considerable delay between the two
> > that produces the effect that you mention. I assume that the HD requires
> > the more sophisticated decompression and hence a longer delay.
>
> Our service provider is ahead of the curve for switching over to digital.
> We no longer receive analog signals.  The decoder boxes are identical and
> the coax runs are practically the same.  (Maybe 3-4 meters different.)
> I wish I had noticed the effect before the switch to pure digital so I
> could compare the effect once the switchover occured.  I may have to drag
> out the old o'scope and take a look...  Wonder how much error that's going
> to put in the system?