[BC] Analogue is better for many viewers

[RichardBJohnson at comcast.net]

An unconstrained (no filter) digital signal only requires a 6dB S/N ratio to completely eliminate noise from the information. With appropriate information-filtering, the digital information must only exceed the noise, and if the digital signal repeats, such as is the case of signals from the Mars lander, etc., even a negative S/N ratio can be accommodated as the signal is brought up out of the noise by averaging techniques. Analog TV requires at least 15 dB S/N to be able to synchronize and at least 40 dB to eliminate all visible noise on a typical B/W receiver (if there are any) and at least 55dB S/N to eliminate visible color noise. 

It is NOT the digital modulation scheme that is the problem! It is that HDTV receivers suck rocks. When enough people complain, perhaps the receivers will have more RF gain. Right now the HDTV receivers are really designed to require at least 100 mV (sic, NOT uV) to work! The input is a "single-chip-solution" that connects the signal input directly into a multiplier where the signal is demodulated to baseband -sort of like a crystal set. There is no RF preselection, and no RF amplification. If it wasn't for digital signal processing, it wouldn't work at all. The emphasis is upon cheap. cheap, and more cheap. Point Google to "HDTV RF front end" if you are interested in these "Muntz" (http://www.madmanmuntzmovie.com/ ) gutless wonders.

Cheers,
Richard B. Johnson
Book: http://www.AbominableFirebug.com/

----- Original Message -----
From: "Stanley Adams" <stanleybadams at yahoo.com>

The signal to noise or interference (Ebno/I) of digital must have a higher
threshold to produce a useable picture than the standard (E/I) of analogue
of old TV.