[treebeard]

I am looking to purchase a RPTV, Receiver, and DVD player very soon. After doing much reading on the receivers in this forum, and doing the compares at various web-sites, I find myself wondering what "component video bandwidth" is.


Crutchfield describes it as:

The bandwidth available to send component video signals to your receiver. You'll need bandwidth over 10 MHz to pass on progressive-scan video without noticeable softening of the picture. And for HDTV signals, you'll need bandwidth in the upper 20s or higher to avoid noticeable softening of the picture (with most TVs).


Some of the receivers that I am considering have NA next to them in this category. Sorry in advance if this is a dumb question, but if the receiver has NA, does this mean that a progressive scan dvd player running through the receiver would not work?


tia

 

[thebishman]

I believe it means that the manufacturer has not listed the bandwidth present in that particular receiver, hence it can't be quoted. BUT, I would be very wary, since it might not be published because it is on the low side. I believe that a minimum of 37MHz is necessary to 'pass thru'' HDTV signals without potential problems with degradation.

thebishman

 

[C Clark]

Although a bandwidth of 37 MHz may be okay, I read here that the video bandwidth needs to be in the 100 MHz range. Several technical discussions that included calculations occurred earlier in the year. (Search the audio forum.)

 

[Drew Eckhardt]

1080i video requires a display rate (including non-visible pieces) of 74.25 million pixels/second.


Nyquist theorum says that this is sufficient to encode a signal with a 37.125 MHz.


Conversely, an analog medium can convey all the image in a 1080i video stream if it's bandwidth is _flat_ (as in +/- 0dB) to 37.125 MHz.


To get that, you'll need a -3dB point of something closer to 50MHz.


Of course, with sources that aren't computer generated the actual detail will be lower in the source material. Unless you buy a 9" CRT based projection TV with a fine enough lenticular lens, you won't be getting the full 1920x1080 resolution.

 

[Mothman]

I'm having the same prob trying to find the numbers on the Marantz 7300.


This site maybe some help on the subject of mhz needed for diff sorts of tv and hdtv. Then again I could be misreading the whole subject and it's back to the drawing board.

http://members.aol.com/ajaynejr/hdtvreal.htm

 

[Mothman]

PS... If anyone has found any info on the component video bandwidth of Marantz receivers I would love to know.


Thanks.

 

[jandrade]

Drew, thanks for the technical explanation. I'm kind of new at this, and I'm also trying to figure out what low to mid-level receiver to buy that has enough bandwith to support a high definition signal. I'm a little confused by your post, in that I'm not sure whether I should look in a receiver's specs for it to say 37MHz or 50MHz under "component video bandwith". What do you mean by "you'll need a -3dB point of something closer to 50MHz"? I hope I'm not the only one that doesn't understand this


Thanks!

 

[amheck]

Why not consider a component video switcher? These will normaly cost around $200 and will have upwards of 200Mhz bandwidth and will allow 4-in and 1-out. Then you can just concentrate on the other features of the receiver that you want.


Aaron