Analog to Digital Converter

[DutyCat]

Ok, someone out there has to know something about this.

In my school, there is a closed circuit TV system. A coax cable comes out of the wall in each classroom. The signal is an analog RF format.

Now, rather than hooking this up to an older TV, what I want to do is pass the signal through a newer DVD player and onwards via RCA jacks to a projection system, so that the image is much larger and my students can see it better. The problem is new build DVD players are set up to receive "digital only" signals. They will not receive an analog signal and it will not pass through.

What I need is an analog to digital converter. One that will take an RF analog signal and change it to a digital format acceptable to a newer model DVD player. All I can find online is digital to analog converters, where modern digital signals are converted back to analog for use in older model TVs and VHS players. I need the opposite of that. I have gone to Radio Shack and Best Buy, and for the typical young pup on the sales floor, this request is so far out of their experience base that I might as well be from Mars.

If their are any audio/video pros here, please chime in of you can help.

[Ben Brown]

Try NewEgg ( http://www.newegg.com/ ). Radio Shack has turned into a cell phone store and Best Buy is, well, Best Buy. One of these might be what you're looking for: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&Description=analog+to+digital+converter

HTH.

Ben

[Hawkeye's Hobbies]

If the source of the signal is digital and the monitor is also digital, then the conduit (cable) shouldn't matter. When my house was wired it was done so using standard coax. When we upgraded to digital television they didn't replace the cabling. Any of my old non-digital television either need a cable box or converter to watch digital programing (our last local station finally converted to all digital broadcasting this past month). However, my digital television could pick up those stations not digitally broadcasting.

As long as your DVD is digital, you should be able to view it using the schools closed circuit system as it is only a network of cables run from a audio/video library room (correct?) where the DVD, video tape players and central television tuner for the building are located and those signals in turn are fed to the classrooms.

If you can't make a digital television work, look at using a LCD projector onto the movie screen in the classroom instead.

[AlanM]

Ok, If I read your post verbatim, you can't do what you want to do with the DVD PLAYER. You would need a DVD recorder which is what has replaced the VCR. You would need to find one with an F connector(RF) input, I think most DVD Recorder/VCR combos should have the inputs you need. HTH.

[KursadA]

What you are looking for is not called an "analog to digital converter". I am not sure I fully understand the setup you're describing; but it looks like there is coax A/V cabling in the school, and you would like to get the video signal from the coax cable and connect it to a video projector. I am not sure I understand where the DVD player comes into the picture. Do you believe that you could connect the video signal from the coax cable to the DVD player, and connect the projector to the output of the DVD player? Sorry, but it won't work. Such a setup would work in an older VCR because VCRs have built-in tuners for recording TV shows; so they have video input ports. A DVD player (unless it is also a DVD recorder/PVR or a VCR/DVD combo) is an output-only device and does not need or have a video input port.

What you need is called an "RF demodulator". Essentially you're looking for a device that would accept an RF video signal and output a line level video signal to an RCA connector. You have two options:

-You can get a purpose-built RF demodulator. A basic TV tuner with RCA outputs would work, too. These cost around $70-100.

-You can get an old VCR. Many VCRs have coax video input and RCA A/V outputs. These are basically almost free via Ebay or Craigslist.

Edited August 13, 2011 by KursadA

[DutyCat]

OK, first off, thanks for the responses. I appreciate it. Here is my set up:

I have a projection system in my classroom with RCA input jacks.

I have a coax cable coming out of the wall which carries an RF analog signal. This is a school wide system which feeds live as well as recorded media.

I have a new model VHS/DVD combo player. I do not think the VHS side has record capability, but I haven't taken a look at it in awhile since we are out of school right now. Pre-planning starts tomorrow, so I will take a look. I will also see if there is a coax input.

I have the VHS/DVD routed to an amplifier,(standard stereo type) via RCA cables. RCA cables are then run to my projector.

I can watch DVD or VHS no problem, but so far at least, I cannot get the RF coax signal to pass through the VHS/DVD player and on to the projector. I have been able to put an OLD VCR in the line and route it through no problem, but that means two components hooked up to my projection system, and I get half channel audio on each.

What I need is something that can format this signal so that it will be usable when passing through this VHS/DVD system.

I will look at the components again tomorrow.

[DutyCat]

What you need is called an "RF demodulator". Essentially you're looking for a device that would accept an RF video signal and output a line level video signal to an RCA connector. You have two options:

-You can get a purpose-built RF demodulator. A basic TV tuner with RCA outputs would work, too. These cost around $70-100.

-You can get an old VCR. Many VCRs have coax video input and RCA A/V outputs. These are basically almost free via Ebay or Craigslist.

After I run the signal through an RF demodulator, can I run it through the DVD player and onward to my projector?

[KursadA]

It looks like you already tried the old VCR method I suggested and confirmed that it works. It will work, because most old VCRs have a TV tuner and have a video input port for this purpose.

A DVD/VCR combo with no recording capability (for the VCR part, obviously) sounds odd to me, but then again I have not seen a VCR or a VHS video cassette since; I don't know; 2004 or so. It may just be that manufacturers dropped the analog TV tuner to decrease cost. I am pretty sure it must have a video input port, though: do you see a group of RCA connectors clearly labeled "VIDEO IN" at the back?

If the DVD/VCR combo has a video-in port; you can connect the RF input of an old VCR to the coax cable, and then connect the RCA video output of the old VCR to the RCA video input of the VCR/DVD combo. Definitely clumsy, but it will work.

If the DVD/VCR combo does not have a video-in port, there is no device that will allow you to pass an RF signal to your projector through it. It simply is not possible. You may look into buying one with a video-in port.

Edited August 15, 2011 by KursadA

[DutyCat]

It looks like you already tried the old VCR method I suggested and confirmed that it works. It will work, because most old VCRs have a TV tuner and have a video input port for this purpose.

A DVD/VCR combo with no recording capability (for the VCR part, obviously) sounds odd to me, but then again I have not seen a VCR or a VHS video cassette since; I don't know; 2004 or so. It may just be that manufacturers dropped the analog TV tuner to decrease cost. I am pretty sure it must have a video input port, though: do you see a group of RCA connectors clearly labeled "VIDEO IN" at the back?

If the DVD/VCR combo has a video-in port; you can connect the RF input of an old VCR to the coax cable, and then connect the RCA video output of the old VCR to the RCA video input of the VCR/DVD combo. Definitely clumsy, but it will work.

If the DVD/VCR combo does not have a video-in port, there is no device that will allow you to pass an RF signal to your projector through it. It simply is not possible. You may look into buying one with a video-in port.

I'll be back in the classroom Thursday and take a closer look. Last year when this problem came up they were talking about buying me a DVD/VCR combo player with a tuner. For some reason, when I called to confirm it would do what I wanted before purchase, the company that had it backed off and said they did not think it would work. I'll maybe look at that again.

You said to plug into the video on RCA jack? What about my audio? I think this was the problem I had before...half channel audio because I only have two audio input jacks...one was taking the TV signal from the VCR and the other was from the DVD/VCR combo.

Edited August 16, 2011 by DutyCat

[KursadA]

I still suggest the old VCR approach. This guy seems to have a bunch of these and wants to get rid of them. Why not give him a call?

http://jacksonville.craigslist.org/bar/2542261022.html

If you have only two audio input jacks (one stereo audio input); then use an inexpensive A/V switcher. Here is one on Amazon for $8.

http://www.amazon.com/RCA-DT902AV-2-Way-V-Switcher/dp/B0014KOAD8/

In short, my suggestion is:

-Junked VCR from Craigslist or Freecycle: $0

-Cheap A/V switcher from Amazon: $8

-Not paying $60+ for an RF demodulator: priceless

Edited August 17, 2011 by KursadA

[DutyCat]

Seems easy enough. I need video from both devices as well. I also have an amp, which hooks to my speakers. I will look at it all tomorrow and experiment a little. Kids come back Monday. Yikes!