World Television Standards

There follows a list of various television standards in use around the world. It's as comprehensive as I can mange, and correct to the best of my knowledge. If you are a visitor from outside the UK and I've missed you out, or you can tell me I've made a mistake then please let me know!

A number of countries appear in more than one standard.

These countries have (or have had) more than one standard in operation.

A quick note on NTSC 4.43 (525 lines, 60 fields, 15.734KHz line, Sub-Carrier 4.43MHz)

This isn't really a standard at all, though it does crop up occasionally. Inexpensive VHS and DVD players which claim 'NTSC playback on a PAL TV' often output NTSC 4.43. They do not perform a standards conversion as such, but merely convert the colour information to something which resembles 4.43MHz PAL. The line and field rates are not modified at all, leaving it it up to the timebase of the downsteam equipment to lock up (hopefully!). On some sets this works well, on others an assortment of squashed looking pictures may result.

A few notes on SECAM

Owing to the somewhat poor documentation (in English at least!) of this format, all SECAM countries have been grouped together in the table above. There are several variations on the theme including horizontal, vertical and MESECAM.

MESECAM  uses an AM colour subcarrier (allegedly) and is popular in the Middle East, where as the original French SECAM version uses an FM colour subcarrier.

SECAM uses only a single FM carrier for the colour information, and so only one colour difference signal can be transmitted at any one time. R-Y and B-Y are sent on alternate lines (a delay line in the receiver makes up for the chroma 'holes' left on every other line). In its original form (so called VERTICAL SECAM) lines 7-15 and 320-328 contained a chroma synchronisation sawtooth. These indicate to the receiver the order of the incoming R-Y & B-Y lines of colour (referred to as DR & DB). Being rather wasteful of bandwidth, this system has been dropped in later sets. The frequency of the colour burst (which is different for each colour difference signals) can be used to make the identification instead. This system is referred to as HORIZONTAL SECAM.

It is interesting to note that most material transmitted in these counties originates in PAL, and is transcoded to SECAM prior to transmission. This is due to the fact that the SECAM signal is difficult to edit, and near impossible to dissolve/mix. This is something of a moot point thanks to the arrival of component production techniques, where the chroma signal need not be modulated onto the luma at all.