Digital Cable

Will a digital cable box enhance the picture on a regular television or would you need to have a high-definition/digital television to see a difference?

      • We upgraded recently, and while there may be some difference in picture quality between an analog and a digital feed to an analog TV, I didn’t notice it. You do see a bit of improvement of a DVD over the same videotape, though. - DougC

You should not expect any significant increase in picture quality with digital cable.

If you plan to get HDTV, that will be on separate channels on the digital line-up and won’t even be visible to you until you have an HDTV set. For example, on a regular TV, you might watch HBO on channel 300 and see that channel 301 is HD HBO, but you won’t see anything if you tune to channel 301. On an HDTV, you would see regular-definition HBO on channel 300 and HD HBO on channel 301.

Hope this helps.

The big difference seems to be the manifestation of transmission errors.

As I type this I am watching an analog channel with interference caused by thunderstorms in Eastern Canada. There’s all kinds of snow of the type you’re already familiar with.

But if I change the channel to a digital broadcast, I get a perfectly clear picture, - except, - when there are transmission errors you get little green squares that pepper the screen that may last a second or two, or the whole screen will go black for a second.

Imagine that you’re watching a sequence of .JPG files. A one-bit error will result in one square chunk of the screen being decompressed incorrectly, or it may prevent the whole frame from being shown.

I can tell you about the digital cable available in my location (Dallas, TX area).

The only channels that were digital where the ones above channel 100. All the rest of the channels were just as they were before. Some of them had noticable quality problems. The “rest” of the channels are the ones you watch the most. The ones that were digital are just the “extras” that you couldn’t get except with digital cable.

The compression rate for the digital channels was obviously very high. MPEG style artifacts were very noticable.

Even though the digital channels got to the house in a digital format, what was output to the TV was standard NTSC quality. The only improvement in quality is that the digital channels never ghosted, etc. Of course, analog channels on cable shouldn’t do that either, but they often do to some degree. An HDTV (which I have) doesn’t make any more of the digital cable channels than the others.

Though the cable box had the words “dolby digital” on it, the output was just a analog stereo pair. There was no way to get true multi-channel sound other than matrix (pro logic) type decoding. If the box fully supported dolby digital, it should have carried 6 analog outs, had a bitstream out that an outboard decoder could deal with, or both. There was no better box available as an option.

In the end, I decided I had had enough.

I recently (in the last couple of weeks) switched to direct TV. What I get now:

  1. I have two true HDTV channels by satellite.
  2. Every channel is delivered digitally, and they look great, no ghosting, etc.
  3. All my audio is coming from a digital output and being processed by my receiver. Whatever format the show is broadcast in, that is what I get. Not everything is created in full 5.1 dolby digital, but if it is made that way, that is how I get it.
  4. I am spending quite a bit less money.


  1. If the weather gets really bad, I can get a loss of signal. It takes a hell of a downpour though.
  2. I bought my satellite equipment, so that is cash out of my pocket up front.

That doesn’t mean that digital cable is just like that in your area. But those are the pitfuls that you need to watch out for. I suggest visiting a friend who has it and check it out.

Also, you need to be aware of the difference between DTV and a channel being carried digitally by cable or satellite for that matter.

DTV, even at standard definition uses a true RGB color space. When cable or satellite carry a regular broadcast digitally, it is still NTSC at heart and uses the luminance/chromanance (sp?) color space. True DTV standard even at normal resolution looks better. For a TV to run in the RGB color space, it must have digital input or (this is how I am running) Red, Green, and Blue inputs (there are several formats of this). All TV’s actually convert NTSC to RGB before it gets to the display tubes, but if the signal is carried in NTSC format anywhere along the way, the color will never be as accurate. A good example is that the red of a sunset is never convincing on normal TV. You may not even notice it any more, as you are probably just used to it. It jumps out at you immediately the first time you see it look correct on TV.

Probably more info than you were after but, the satellite reciever that I am using also has a terrestrial DTV/HDTV tuner in it as well. I am subscribed to my local channels by satellite, but also get the ones that have a digital transmitter up a “second” time. This makes it easy for me to compare NTSC and DTV of the same broadcast side by side. The satellite gets the NTSC to me about as well as I have seen it, but DTV looks much better color wise. And if the the local broadcast is in HDTV, there is truly no comparison at all.

As your location info isn’t filled in, I don’t know where you are located, but… if you happen to be in the north texas area, I would more than happy to show it to you first hand.

First off, Digital does not = better quality. Analog media have a bad rap, but analog data for images and sound is superior. Even when the signal is good (not that often) I get a lot of digital artifacts. Flashes that are blocky, jerky movements, etc.

Remember, the cable co.s are selling you digital primarily so they can shut off the analog channels and force you to use their box for everything. I.e., charge your more $$$ even to just record one basic channel and watch another.

Thank you very much. You have all been helpful.