Digital Television Explained

The other evening, whilst enjoying another gripping episode of "Deal or No Deal" (which I daily pre-record and watch at four times speed over my evening meal), the present Mother-in-Law telephoned BuddlementTowers in a distressed state, wondering why she couldn't get a clear picture for Channel Five and QVC on her Digibox. The reason for her angst was that she couldn't get her weekly dose of Gary Sinise in CSI:New York and had to content herself with Hugh Edwards on the Nine O'clock news discussing the 210 kilos of Russian Polo mints (again).

I quickly identified her predicament as a clear case of poor reception on one particular multiplexer or MUX; however how can one easily explain this to someone not familiar with finer technicalities of modern broadcast television? I quickly came up with a simple analogy and I thought the technically challenged amongst you, may find the explanation I gave, of use.

"Let us compare television to toothpaste.

Analogue television is rather like brushing your teeth with a simple mono-colour toothpaste (such Colgate freshmint... other toothpastes are available). You select a channel (or toothpaste) and clean using a toothbrush (or television set). However, what if you only had multi-striped toothpaste (such as Aquafresh), but yet still wanted to enjoy the same, simple delights of a mono-coloured dental cleaning product? This is where the Digibox comes in. A Digibox separates the multiplexed toothpaste into it's constituent parts (or channels). Multiple channels (or toothpaste stripes) are broadcast on the same multiplexer (or toothpaste tube) and arrive on your Digibox or bathroom shelf. The user (or Digibox) would then delicately de-multiplex, or separate, each stripe on the bathroom shelf, into single strands of red toothpaste (Channel Five), blue toothpaste (QVC) and white toothpaste (Bidup TV), before placing them onto separate individual toothbrushes, or slots in the Electronic Programme Guide (EPG). The viewer, then selects the appropriate toothbrush, unaware of the other multiple channels, or toothbrushes. These toothbrushes are all broadcast on the same MUX or toothpaste tube. If however, your tube of Aquafresh emerges in a single strand of purple toothpaste, the digibox cannot decode the toothpaste into the separate channels and Gary Sinise, ends up looking like one of those pixilated villans as seen on the excellent ITV programme "Police, Camera, Action!""

I hope this makes things clearer.