Im using my vcr just as a UHF modulator (analogue) but analogue is becoming obsolete, and im thinking of doing away with the vcr, and getting a tv with digital tv tuner but no analogue, is there an equivalent modulator for digital TV ?
I already have UHF coax and I dont want to have to run a multicore cable, and it would be so useful if it didnt need a seperate demodulator but could just use the internal digital tuner.
a search for such a thing seemed to show up modulators to connect freeview boxes to analgue tv UHF input.
just need to send it down the tv areal lead, or maybe tramsit it a few feet through a wall or ceiling, to the next room.
All TV is analogue at the receiver at present. You would need an MP2 encoder for digital - then decode it with a set-top box (like a sky receiver) and then re-modulate it in the usual way to show it on a TV. Digital TV is a misnomer - the receiver is still analogue after the MP2 decoder box - it's the modulation and encoding method that differs. Having said that though, LCD TVs are going digital in the sense there is no CR tube.
The digital TV broadcast is a digitised signal, the new TVs with a built in digital tuner can receive the basic digital broadcasts with no extra box, Im not sure what the modulation sheme is but although the front end amplifiers etc may be anlogue, the signal still contains digital information, so its still a valid distinction. some of the newest TVs come with only the digital version tuner can not receive the old non digitised fully analogue transmision, its becomeing obselete and is being phased out here, as almost everywhere now receives digital broadcasts, the analogue transmisions will be switched off over the next decade.
I cant see the advantage of encoding then decoding then modulating as you suggested, I just want to convert a signal into something that can be received directly by a tv with only a digital tuner. ie where the tv contains the necessary tuner to demodulate and decode.
presumably just needs a digitised source of the correct type, such as mp2 you mentioned, from a pc this is easy, and UHF modulator, im not sure what the scheme used is or if theres any control information etc. the old system was relativly complicated with sound, chroma, luminence signals and PAL etc, I would think just modulating bits wouldnt be beyond the possibilities of a small module. a digitizer and mp2 encoder would
Ive seen you can get USB digital tv broadcast receivers.
I gues the market just wouldnt be there as it was for analogue when the old tvs only had an aerial input and no other way to feed video directly.
"colin" wrote in news:Vfxai.10210$ snipped-for-privacy@newsfe5-win.ntli.net:
Not at the consumer level.
Consider putting a simple tuner/analog demodulator at the TV, if it has no analog tuner built in. Or just send composite video to the display, and play sound from a separate sound system.
Best thing I ever did, when we built this house... I had them add 3 spares of RG-6 between the home theater area and the central cable company distribution area.
...Jim Thompson
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| James E.Thompson, P.E. | mens |
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"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
ive got quite a few cables going through 1 or 2 walls atm, rather than put more through I was hoping to mostly get rid of them, I also want to be able to move things round a bit easier, with a new tv in the main room, I dont have a theater area as such, also a new tv in the bedroom where there is no cable or conduit, new tvs seem a fair bit cheaper with just the digital tuner rather than both.
it would be ideal to have some wirless system and do away with cables, less for the cats to chew through ! although they dont seem to have chewed thru the usb cable for the kittycam by the food bowl.
if it was possible to send and receive all the audio and all video via the same system that would be so cool, as there is there are so many diferent systems as for wirless you can get microwave video senders, wifi, bluetooth etc ...
When my mother built her house, about forty years ago, I put outlet boxes with conduit to the attic area for cable and stuff. You never know what sorts of cable will be needed. The conduit made it easy to snake whatever is needed.
Sometimes I can snake a cable after, but I've had to open holes in walls in this house. It's a PITA and blank wall plates are ugly.
in a few years I expect you'll be able to run those signals through a cat6 network cable, or possibly wireless lan with no loss, but currently there's a technology called HDMI and a bunch of stupid laws that restrict how you can distribute the video signals.
I thought that is what they made medium to large FPGA's development kits for. Sure you have to do some Verilog or VHDL, that is the fun part. Can you say software defined radio?
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JosephKK
Gegen dummheit kampfen die Gotter Selbst, vergebens.
--Schiller
how much could you do in the fpga ? just the modulation to feed into a uhf freq shifter ? perhaps usb interface that would be usefull, or maybe do the mp2 encoding too, or even analogue video in too, say composite or whatever, although theres probably a chip that would do the a/d nicely, or hdmi ...
if it was a fpga and a uhf mixer that wouldnt be so hard to do, although software always takes longer than you want, and those fpga are awfully tetchy about being soldered deadbug style, i dont know how big those kits are.
I would imagine just trying to interpret the standards would be hard enough judginbg by the way many such things are becoming more and more complex.
and would anyone else realy be interested ? might be cool if there was some shared effort. no ones come up with a commercial offering yet so I assume there isnt one, save for broadcats studios.
On Jun 11, 2:17 am, Jasen wrote: > On 2007-06-10, colin wrote: >
In a few _years_? You can do that today as I've been watching HDTV over cat 5 cable for over a year. You need an HD tuner and a home network. The computers don't need to be rockets either but you will need large drives as HDTV can use up to 8.7 gig/hour.
I figure that 1 or 3 a-to-d converters for the analog input, 2 d-to-a converters for the baseband / if (40 MHz or 70 MHz) output, a uC to load the FPGA, a FLASH chip to store the programs, and the modulator out of a standard tv converter. (yes the primary difference is the baseband signal content).
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JosephKK
Gegen dummheit kampfen die Gotter Selbst, vergebens.
--Schiller
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