Seven-day wonder: Inside the Promise TV

Seven-day wonder: Inside the Promise TV

Summary: Modern consumer products need hardware, software, industrial design and usability. Find out what two designers can do with Promise TV, a set-top box that records seven days of Freeview at once


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  • Circuit board

    In the semi-rural idyll of Ascot, the Ludlam family has come up with a set-top box with a difference.

    Promise TV records programmes from terrestrial digital Freeview, but unlike other systems, it doesn't rely on the viewer selecting shows to record. Instead, it records everything broadcast over seven days: every show transmitted on all 40-odd radio and TV channels, without pause. Recordings are grouped by category, as well as time or date, so it's like a constantly renewed watch-on-demand service.

    The family, led by husband-and-wife team Richard and Kate Ludlam, handle everything to do with the Promise TV system themselves, including case design and prototype production. Sons Dominic and Christian Ludlam take care of the software and hardware design, respectively.

    One of the trickier design problems on the Promise TV was the tuner board, the Ludlams told ZDNet UK. With up to six multiplexes to receive simultaneously, the incoming signal needs to be to split between six radio receivers, and the six 24Mbps decoded data streams need to be continually sent to the recording circuitry.

    Radio frequency signals in particular are very sensitive to board layout, digitally generated noise and cross-talk between circuits, which makes design something of an art. Here, each receiver has three chips and a couple of filters, effectively producing a 144Mbps one-way wireless network card that works over many tens of miles.

    Image credit: Rupert Goodwins/ZDNet UK

  • Promise TV box

    This is the remote head that links a TV to Ethernet while relaying infrared control codes from the remote. Up to four of these can be fitted around a building and connected back to the main box.

    The natural length limitations of single-span wired Ethernet and the deliberate lack of wireless make it very hard to use this system to distribute TV outside a single building. The company hopes this will placate any broadcaster nervous that its content rights are being infringed.

    Image credit: Rupert Goodwins/ZDNet UK

  • EPG screen

    A major advantage of the Promise TV system is its ease of use and guaranteed capture of wanted programmes — potentially even before the viewer knows they want to see them.

    Dominic Ludlam, the software designer, has eschewed the grid system so common in other electronic programme guides (EPGs) for a simple timeline or content grouped by type.

    Here, part of the list of the hundreds of films that had been broadcast in the week prior to ZDNet UK's visit is shown. Because it's unlikely the viewer would care when the film was broadcast, the time isn't shown. With news or sport, however, that information is displayed. 

    Image credit: Rupert Goodwins/ZDNet UK

Topics: Storage, Emerging Tech

Rupert Goodwins

About Rupert Goodwins

Rupert started off as a nerdy lad expecting to be an electronics engineer, but having tried it for a while discovered that journalism was more fun. He ended up on PC Magazine in the early '90s, before that evolved into ZDNet UK - and Rupert evolved with them into an online journalist.

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  • Oh very nice!