What is QAM? and also...

[Madtown HD Junkie]

What is QAM (hope that is right)
Also I have heard my RCA 210 HD tuner can receive my local cable companies QAM siganl and decode it so I can watch it even though i only have cable for interent? sound right? Not trying to get something for free but i don't want to miss out on a free thing either. I had heard they have to broadcast the QAM thing due to law??? any help me thanks.

 

[charper1]

I think it stands for Quadrature Amplitude Modulation and thus:

a method of combining two amplitude-modulated (AM) signals into a single channel, thereby doubling the effective bandwidth. QAM is used with pulse amplitude modulation (PAM) in digital systems, especially in wireless applications.

In a QAM signal, there are two carriers, each having the same frequency but differing in phase by 90 degrees (one quarter of a cycle, from which the term quadrature arises). One signal is called the I signal, and the other is called the Q signal.

Mathematically, one of the signals can be represented by a sine wave, and the other by a cosine wave. The two modulated carriers are combined at the source for transmission.

At the destination, the carriers are separated, the data is extracted from each, and then the data is combined into the original modulating information.

 

[Neutron]

I don't see how it would let you watch something on your cable company's digital system as you would still need their box to decode it.

 

[shappyss]

even if it could recieve QAM signals i think u would need some type of access card from the cable company and still require a subscription

 

[Scott Greczkowski]

My Zenith HDTV in my bedroom has a built in QAM tuner, and with it I can receive a bunch of unscrambled Digital Cable Channels all the Digital Cable Music Channels plus all the local HD Channels which my cable system carries.

On MOST cable system the local HDTV channels are not scrambled and can be received with a QAM tuner.

 

[charper1]

On MOST cable system the local HDTV channels are not scrambled and can be received with a QAM tuner.

Is this a "law" or just happenstance?

 

[Neutron]

How can you tell if your receiver has a QAM tuner? I know my HTL-HD has a Cable-IN coax jack but I don't think it's QAM compatible.

 

[Scott Greczkowski]

Is this a "law" or just happenstance?

The way the law is written is says that OTA Locals "should" be provided unscrambled, it does not has that the OTA Locals HAVE to be provided unscrambled.

Problem is if you call your cable company and ask they will tell you you need a HD Digital Cable Box, not only so they can get $5 a month more out of you but they also hope you subscribe to Digital Cable and use Pay Per View and their VOD services.

 

[charper1]

How can you tell if your receiver has a QAM tuner? I know my HTL-HD has a Cable-IN coax jack but I don't think it's QAM compatible.

Check your user guide specs and it will say, or visit the make/model's website.

 

[shappyss]

i did a quick read of the user manual for that model and didn't see anything about QAM tuner but I might have missed it

 

[charper1]

EXAMPLE of my LG LSS-3200A

The 3200A receiver has ATSC (high definition), NTSC (standard definition) and DIRECTV® tuners so it is able to process both over the air (OTA) and satellite signals as well as unscrambled cable (QAM). It integrates all stations into a single programming guide that is flexible and generally quite fast. This is either the only receiver you need or a great supplement to any integrated tuners your TV may have.

The back panel is fairly simple yet surprisingly complete. It has inputs for the DIRECTV® antenna feed, a cable connection, and an OTA antenna connection. It has single video outputs in the following formats – DVI (with HDCP), RGB, component, s-video, composite (two of these) and RF. The RF output can also be used to loop through the OTA or cable signal (but not both) when the unit is in standby mode. There is a 2-position switch for selecting either component or RGB/DVI. The s-video and composite outputs are always active, which is one of the major improvements.

There are two sets of stereo audio outputs and one optical digital audio output. There is no coaxial digital audio. There is an RS-232 data port and the standard phone jack for ordering pay per view programming. There is also an IR blaster output to make it easy to interface the 3200A with a VCR and an input for using the remote control in RF mode.

The front panel is even simpler. Besides the typical power and cursor buttons, there are buttons for the Display Format, Info, Menu, Guide, Select and Exit functions. All of these are duplicated on the remote with the exception of the Display Format function. The display is very easy to read in all lighting conditions from several feet away but is not obtrusive in a dark room. The access card slot is also in the front.

 

[Neutron]

Found a website that sells the HTL-HD and it said this:

Hughes, being the parent company of DIRECTV means they’ve been around since the beginning of the commercial satellite business and are satellite experts. Their products are always well engineered and rank among the highest in customer satisfaction. The HTL-HD has lived up to these standards with advanced connectivity able to receive ATSC, NTSC, QAM (Unscrambled), HDTV and DIRECTV signals. This receiver also has the main connectivity including component, s-video, DVI and composite jacks.

The only other question I have is if my local cable company's local HD channels are unscrambled, could I view them properly on the HTL-HD, in HD?

 

[charper1]

That might be a local friend or buddy question, or even a self test.

 

[Neutron]

Since my apartment complex forces me to subscribe for basic and classic cable (I tried really hard with both the cable company and the apartment complex to get out of this) and is included with my rent I may try it this weekend.

 

[VewDew]

Ok, you have piqued my interest. Does the new DVR HR10-250 have this QAM capability?

 

[charper1]

Here is a SPEC LINK and I didn't see QAM mentioned.

 

[Neutron]

There's not a cable-in jack on the HD DTivo either.

 

[robert luzzi]

you did say that the complex you live at denies you the right to get satellite. AND that it is included in your rent??!!??!!

THAT IS ILLEGAL

PERIOD

......bob

 

[Neutron]

Oh no!! I have Directv satellite just fine!! They have no problem with it. Included in my rent is basic and classic service, $39 a month extra that is in my rent. I can't get out of that. I've tried on both ends of the problem.

Now if they did tell me to take my dish down we would have problems.

 

[slacker9876]

I think it stands for Quadrature Amplitude Modulation and thus:

a method of combining two amplitude-modulated (AM) signals into a single channel, thereby doubling the effective bandwidth. QAM is used with pulse amplitude modulation (PAM) in digital systems, especially in wireless applications.

In a QAM signal, there are two carriers, each having the same frequency but differing in phase by 90 degrees (one quarter of a cycle, from which the term quadrature arises). One signal is called the I signal, and the other is called the Q signal.

Mathematically, one of the signals can be represented by a sine wave, and the other by a cosine wave. The two modulated carriers are combined at the source for transmission.

At the destination, the carriers are separated, the data is extracted from each, and then the data is combined into the original modulating information.

Please remind me to NEVER question you in the future I thought I could get technical until now. Well it will give me something to look at in my spare time at the office.

Too bad, I would have kept my HTL-HD had I known this. I may sell mt HR-
250 anyway. I have been thinking A LOT about what is coming and I may pickup an R10 tomorrow and try one out for a month.

QAM is built into many devices, it is the reason 2005 will be the year of cable, but we all know 2006 belongs to D*!!!