Letter: Digital debate

Sir: Gavyn Davies makes the glib comment that "digital television is simply a superior technology to analogue television" as part of his justification for forcing pay-TV on the UK viewer ("What can I do to make you go digital?", 21 September). Whilst digital technology may provide better suppression of interference in some cases, all of the digital systems available in the UK use data compression to squeeze many digital channels into the space required by a single analogue channel. Whilst the commercial advantages of this economy are obvious, this contrasts with the introduction of the CD for music reproduction, where the digital system was intended to provide the same or better performance than the analogue system (vinyl LPs) which it replaced.

Data compression relies on the similarities between successive frames of a television picture to discard redundant information, but is often detectable and can be seriously irritating with fast-moving images or complex edit sequences. The picture quality is visibly inferior to that of a good-quality analogue television with an effective aerial.

The many commercial organisations standing to gain from digital have misled the consumer in this regard, with high-profile advertising claiming better picture quality as an advantage of their digital services. The reality is that we are being asked to pay money for a reduction of the signal fidelity.

If Gavyn Davies wants me to "go digital", equalling the performance of the existing analogue service would be a good start.