What are NTSC, ATSC, and QUAM tuners?

Here's a breakdown and how you can use them.NTSC - This is your analog TV tuner that is built into every VCR and Television in America. Basically its purpose is to bring in ANALOG broadcasts. Will receive Cable or Antenna Broadcasts. It will be in every TV that you buy.ATSC - This is the Hight Definition Tuner that by this time next year is required to be in every new television 20" and larger. Its purpose is to receive OVER THE AIR (OTA) broadcasts from local channels via an Antenna, not cable. To utilize this you will need to connect an Antenna, whether a roof top or attic mount and depending on your situation even a table top antenna will work to receive the local HD broadcasts. So when you see the icon in the bottom of your screen now that says available in HD/5.1 this is where you would need an ATSC tuner with an Antenna to receive them that way (or through HD Cable, or Satellite in some cases).QAM - is a High Definition Cable tuner. Used to receive HD Cable broadcasts without a box, just connect your coax directly to the Television. You will need to pay for the programming from your cable provider. However, maybe 2% of the cable companies in the US have this as an option currently (they want you to rent their boxes instead).There's also Cable Card - which works with the QAM tuner to receive HD Cable without a Box. Basically you pay your cable company for the card (rent monthly like a box), but instead of having a box on top of your TV and wires to mess with, you put it into the back of your Television like a disc (similar to a PC slot on a laptop if you are familiar). This works like a box, and the QAM tuner on your TV does the tuning.It all comes down to your source. If you're going to do HD Satellite, then it really doesn't matter what connections your TV offers, because it will connect via Component Video or HDMI and will bypass the tuner inside the TV. For local HD Channels most are available in big cities through DirecTV HD and their new equipment, but if you don't want to mess with the upgrades, all you need is an Antenna for all your local broadcasts (through the ATSC tuner) and use standard DirecTV for everything else.If you're doing Cable, the same thing applies as listed with Satellite, unless you are going to use the Cable Card, then you must have a QAM tuner in your set, and Cable Card Capability.The most important thing to know is what your source is going to be, once you know this, then it will help in determining what is right for you.