What you need to know before buying a HDTV

What you need to know before buying a HDTV
Will my HDTV look like it does at the store?



Introduction

The days of going down to the local electronics store and picking out a TV based strictly on what you can afford and what size you need are gone. The FCC has mandated that all broadcasts be digital by December 31, 2006. This deadline may change due to the fact that the mandate also states that 85% of the TV households in America must have HDTV before the old standard is done away with. Regardless of when it happens, it will happen.

In this article I will explain what you as a consumer needs to know and what to expect when shopping for a HDTV display device. This will be a basic description of the terms and the necessary information you need to know.

Resolution

The "resolution" is the format the image is displayed on the screen. There are a lot of terms you will hear regarding resolution; 480i, 480p, 1080i, 720p etc. The "i" stands for interlaced and the "p" stands for progressive scan. For the purpose of this discussion suffice it to say that "p" or progressive scan in the same resolution is better than "i" or interlaced scan. This is because the progressive scan has twice the lines of video information as an interlaced image. The more lines of video, the "smoother" the appearance of the picture will be.

The main point for a consumer considering the purchase of an HDTV display, is that any equipment such as set top boxes (STB's), cable or satellite receivers have the ability to output the same signal format as the "native" resolution of the display device or monitor. So, what is "native" resolution? Most HDTV display devices takes any signal applied to it and converts it into one of the resolutions listed above. Because of this, you will get the best results from your purchase if all signals applied are the same as the native resolution. For example; one of the most common native resolutions is 1080i. If you apply a 480i or 480p signal to it, the monitor will have to "up convert" the signal to its native resolution of 1080i. Conversely, if you apply a 720p signal it will have to "down convert" it to 1080i. Any additional processing of the applied signal such as up converting or down converting can cause distortions of the image. Therefore, it is in your best interest to have everything operating at the same resolution.

Is it really HDTV?

When shopping for HDTV displays and monitors you will undoubtedly see terms such as "digital or HDTV ready", "digital or HDTV capable," and "digital or HDTV receiver." Be careful with these terms! Digital or HDTV ready means that the device has the ability to receive digital and HDTV signals but may or may not actually be able to display a HDTV image on the screen. Digital or HDTV capable means that the device will display a HDTV image on the screen, but needs an external source for the HDTV signal, such as a HDTV set top box, cable, or satellite receiver. Digital or HDTV receiver, also called “Digital or HDTV TV's,” will have a built in tuner, satellite, or cable receiver that is capable of receiving digital and HDTV signals.

Where do I get HDTV signal from?

There are a number of sources from which you can get an HDTV signal. You can have an antenna installed, and with the use of a set top box or a built in "atsc" tuner, you can receive HDTV signal for free from your local broadcast channels. You can contact your local cable company and have them "upgrade" you to HDTV; which will require them replacing your old "analog" cable box. You can contact a satellite signal providers and have them provide you with an HDTV signal. There are also "progressive" scan DVD players and HD video game consoles that can provide you with the necessary signal for your HDTV experience.

Audio for HDTV

Most HDTV programs are broadcast with 5.1 Dolby digital audio. To truly experience this audio you will need a Stereo receiver or processor that is capable of processing 5.1 Dolby digital audio. This also requires more speakers than are available in the display devices. Generally, you will need 2 main speakers, 2 rear speakers, 1 center channel speaker, and 1 subwoofer. When configured properly, this set up will give you incredible audio to go with your incredible picture. Don't worry, you can still hear the sound with just the TV speakers or 2 stereo speakers and an amplifier, it just won't sound the way it is intended. You will need to make sure the display device you purchase has speakers, some do not. This is especially true when it comes to Plasma displays. There are a lot of them that do not have any audio processing capabilities at all and will require an additional amplifier and speakers.

So, will it look as good when I get it home?

The easy answer is yes, provided you have applied the correct signal to the display when you get it home. The main problem that causes complaints with picture quality on HDTV displays is due to the wrong signal!

The most common reason for bad picture quality, is people getting it home and connecting it to their old analog cable, satellite receiver or outdoor antenna. Analog signal looks bad under ideal conditions. If you take this poor quality signal and apply it to a display that is designed to reproduce the picture as accurately as possible, then you get poor signal quality and poor picture quality. Do not call your local repairman or the manufacturer. They cannot "fix" it, because it is not broken.

Make sure you have the proper signal format applied to the device! If you have multiple signal sources and some are not HDTV, make sure you have selected your HDTV source. If your STB, cable, satellite box, etc. have the ability to select their output resolutions, then make sure you have selected the correct one for your application. Remember that standard DVD players/recorders, VCRs and other such devices are not digital or HDTV unless they are "progressive scan" devices.

Summary

I have barely touched on the highlights of all the issues regarding Digital TV or HDTV. It would require a book to explain everything. Hopefully, the information provided here will assist you in making decisions regarding what to purchase when shopping for HDTV devices.


About the author:
Steve Sweeney
I am a 32 year veteran in electronics repair with experience in fixing all aspects of consumer electronics.
http://www.DiscussElectronics.com