[mythtv-users] Questions about Hauppauge HD-PVR (1212)
Marc Randolph
mrand at pobox.com
Thu Jul 3 21:13:35 UTC 2008
On Thu, Jul 3, 2008 at 1:12 PM, John Welch <jrw3319 at gmail.com> wrote:
>> u could always use a longer USB cable and keep the HDPVR near the TV.
>>
>> Cheap usb cables/extenders can be found at monoprice.com
>>
>> Mitchell
>>
>>
> Thanks. I am considering running a long USB cable, with appropriate
> repeaters. However, if the heat from the unit continues to be a
> factor I would much rather have it in my basement. Also, isn't it
> just as likely that the long USB run will introduce problems as it is
> that the long component video will cause problems? I mean, there's at
> least one poster in this thread that is saying he's running 40+ foot
> cables with just a splitter, and is not seeing any quality
> degradation.
Kinda comparing apples and oranges there - one is a digital pipe while
the other is an analog signal. The short answer is no, it isn't as
likely. But that assumes that the run isn't so long that the USB
signal has bit errors. Once you have bit errors, then USB is
basically useless. By using a repeater on USB, you can keep this from
happening and achieve (near) perfect data transmission.
Component video signals are analog - so there are inherent losses in
signal transmission. Not only are they to subject to interference in
some situations that you can't easily fix at the receiver, but there
are several kinds of unavoidable losses associated with transmitting a
signal down a wire that (in general) a receiver can't completely
compensate for either. It simply displays a filtered (and amplified)
version of whatever non-perfect signal it receives. Using an inline
amplifier can help the situation some by keeping the signal strength
high (SNR) compared to the losses and noise, but it will always have
some amount of noise.
In short, analog (component video) fails gracefully because it has a
continuous range (really good TO really bad) while digital (USB) is
all or nothing because it fails catastrophically (really good OR
really bad).
Marc
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