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Analog FAQ

Why do some of my basic cable channels look worse than they did before I got this " HD DVR digital cable box?

Related questions and answers:

1. Do you use the box to view HDTV channels?
1. If yes: The improved HD pictures often make the basic cable channels look worse by comparison.
2. If no, see next question.
2. Are you familiar with the DVR capabilities of the box?
1. If no: The DVR in this product offers such convenience features as pausing live TV, one touch recording, fast forward etc. These benefits are not available on other set-tops. Once familiar with DVR see 2b.
2. b. If yes: The circuitry that enables the DVR functions can on certain non-digital channels distort the image slightly. The distortion is usually a minor fuzziness. If the distortion is more than a slight fuzziness, then contact your cable provider. There may be a problem with either the set-top box or the signal into your home.

In depth information

This is not a simple issue. In order for your cable operator to deliver you services like HDTV, they must send a digital signal to your home, alongside the current analog signal they send for other channels. The cable box you have must decipher both of these signals independently. In order to record current analog channels on a Digital Video Recorder (DVR), it is necessary to digitize the analog video. This digitization process does introduce artifacts into the analog video which some viewers find objectionable. As your cable company converts more of their analog video services to digital, the number of such channels where you might notice a distortion of the image will decrease.

The advanced digital processing equipment in your cable box is different than a standard analog television tuner. Putting the non-digital (analog) TV signal through a digital conversion process to allow it to be recorded does slightly affect the look of the video. These video artifacts are subjective, and some consumers find them more objectionable than others.

What you can do about it: You can bypass the digital processor by adding a cable splitter. One output of the cable splitter would be directly connected to the coax input on your TV, while the other output of the splitter would attach to the DVR set-top box, which would then be connected to a different input on your TV (such as "Video 1" or "Auxiliary Input"). To switch between analog content and recorded DVR content, simply switch the inputs on your TV.

This configuration will also allow you to watch a basic cable channel while recording a different program on the cable DVR. However, you should note that you will not have use of the interactive program guide or the DVR functions (like pausing live TV) while you're watching the basic analog cable channels. Further, if you record a basic cable channel it will still have to be encoded into a digital format to be saved on the DVR hard disk drive and will therefore contain the picture faults you avoid by watching with the cable splitter.

What we are doing about it: We are working on a next generation of analog-to-digital encoding with more sophisticated picture improvement techniques. This will improve the situation, but will not make converted analog pictures look as good as pictures that are originally created in a pure digital format or transmitted in a digital format.

More in depth information:

Standard non-digital television signals or analog television signals are very different than digital video. Analog television signals often pick up some interference as they travel through air or the cable network. Technicians call the interference "noise". This noise manifests itself as "snow", blurriness, or other picture distortion depending on how much of this "noise" interferes with the original TV picture information.

The signal-to-noise ratio is usually optimized by the cable network technicians, who will provide amplification and/or filtering to make sure you receive a good signal to your home. However, other conditions in your home -- such as loose cable fittings, splitters, or switches -- can cause signals in the air to "leak in" or "ingress" other interference into the cable line around your home, which will result in more noise in the pictures. However with a standard television and with no digital processing, a certain level of signal-to-noise is more tolerable in the picture.

High-definition video signals, along with the information saved on a digital video recorder, are digital. The digital encoder inside your DVR turns the TV picture into digital information which can be saved on the hard disk drive. This means that when the encoder receives an analog signal, it will turn every element of the picture into a digital form with a specific address location for display on a high resolution TV screen.

The computer processor that digitizes the picture must interpret everything that it receives in some way, so when it receives a noisy picture, what you end up seeing on your high-resolution monitor is a picture that contains a combination of the encoder's "interpretation" of the noise and what your TV's processor does with it. Basically, it's a digital copy of a digital copy of interference. By bypassing the digital box and input directly to the TV, only the digital processor in your TV handles the information and the picture comes out looking better.

Miscellaneous:

Compared to high definition pictures the processed analog pictures look much worse and become less tolerable.

Different digital TVs use different digital processes. Some are less forgiving than others, so picture quality varies from TV to TV. Some more sophisticated and more expensive sets have noise reduction technology that can improve the picture.