modern TVs and composite video

[Mark Carver]

An analogue TV signal had a single main vision carrier, and FM and NICAM sub-carriers. With all the sidebands etc it would occupy an 8 MHz wide chunk of spectrum.

A DTT mux occupies the same 8 MHz chunk, but it is composed of 8000 separate carriers, each carrying a very low speed digital signal. The data that composes that mux is spread and interleaved amongst those

8000 carriers. It requires Fourier mathematics to decode that signal down to a digital stream, that is then split up into individual services,

In other words you can't just take an analogue TV tuner, and stick a digital decoder on the output of it, there is no main carrier for it to lock on to for starters

[The Natural Philosopher]

multiplexed onto one of 5 or more carreiers deoending on the multiplex

600-900 IIRC

Nope. Its an Mt2 stream at either 2-3Mbps for DVB-or 4-5 at HD.

Oh... 24Mbps for the whole multiplex? could be.

Does contain several channels ALWAYS.

depending on how the 24Mbps is allocated.

Technically a multiplex or frequency, not a channel

[Mark Carver]

No, 8k or 32k for DVB-T2 muxes  in the UK (although the DVB 'toolbox' allows options from 1k to 32k)  BTW those are not exact carrier values,

8k is actually 6817 carriers.

No, 470 MHz to 750 MHz  (Ch 21 to 55) From next June the UK TV band will run from 470 to 693 MHz (Ch 21-48)

No, typical mux payloads in the UK are 24 Mb/s for DVB-T and 36 Mb/s for DVB-T2. Local TV muxes are 10 Mb/s (to make reception more robust for their Tx powers)

No. There's a mux from Ridge Hill near Hereford that only carries a single service. ITV West

[Brian Gaff (Sofa]

Well, some have inputs some have outputs but many have neither and some just don't seem to know. I can play it via composite on my Samsung of last year, but you cannot get anything out, so if you wanted to vhs anything you would need some kind of dongle or something.

I have one that allows the pc to use hdmi into the telly. Brian

[Brian Gaff (Sofa]

I am given to understand that in India a lot of tvs have analogue still. However many over there still use vhs, so I guess any company will research their markets. If they can save a few pence by not having the chips and sockets they will!

Brian

[Dave Plowman (News]

Out of interest, has anyone ever got one to work?

Ask because I bought one to use with an old Topfield with SCART only. And the Ebay ad said it would convert RGB to HDMI. Didn't work. Tried it with a few different TVs etc too. The Topfield works normally into a TV with a SCART.

Sent it back for a refund. Bought a different one from Ebay - same result.

Remember buying one to convert VGA to HDMI. That didn't work either. ;-)

[Chris Holmes]

Thanks everyone.

And thanks especially for the link to the composite to HDMI converter.

I had searched for these, but the ones I found were way more expensive.

[Chris Holmes]

Perhaps not?

Or maybe not this side of the ditch?

Or maybe not the cheap ones.

In other news I was really surprised to find cheap DVI to VGA and DVI to HDMI converters do work (most of the time (and the latter even work back to front (HDMI out of laptop into DVI on monitor))

[David Wade]

You have to be careful with "SCART". It can be either Composite or RGB. Which was the Topfield? I have a couple of these:-

and they have worked fine on my old computers with RGB into an LG TV

Dave

[Adrian Caspersz]

This idiot ...

The Best Easy Way to Capture Analog Video (it's a little weird)

Ah... he is a Canuck.

DVI comes in two flavours, DVI-D and DVI-I. The latter has pins that can output VGA analogue video.

Not all monitors with DVI inputs are HDCP compliant, which may limit some feeding of HDMI signals to them.

[Dave Plowman (News]

I've found DVI a bit more tolerant than HDMI. No idea why.

[Dave Plowman (News]

You can select what you want in the Topfield software. Think it may also do S Video over SCART.

But even if selected to RGB, the composite signal should still be present on the SCART.

[Mark Carver]

 If it has RGB connections, it has to have Composite too. Because there are no syncs carried in the R, G or B signals, the telly derives the syncs from the Composite line

[williamwright]

It's just a matter of semantics. In popular parlance the word 'tuner' means 'receiver', approximately!

Bill

[williamwright]

There's a mux on my TV system that only carries one channel.

Bill

[SH]

your CCTV mosaic picture via a DVB-T modulator by any chance? :-)

[jkn]

Calling Coded Orthogonal Frequency Division Multiplexing (COFDM) 'analogue' is stretching the original meaning of the term 'analogue modulation' quite a bit beyond a useful point IMO.

[Max Demian]

You might as well say, for an old fashioned analogue radio, that the "tuner" is just the tuned circuit and disregard the frequency changer, IF amplifier and demodulator.

[Fredxx]

DVI is essentially HDMI without the audio, but with analogue VGA added.

The DVI digital signals levels, to my knowledge, are the same as HDMI.

I guess the DVI connector is more rugged.

[Fredxx]

Do you mean you still need composite blanks and syncs on the composite pin? It doesn't actually need real video.