Re: How can digital be more spectrum efficient than analog ?
- From: Stanislaw Flatto <compaid@xxxxxxxxxxxxxxxxx>
- Date: Mon, 30 Oct 2006 02:55:05 GMT
no-top-post wrote:
It's common knowledge that digital technology gives more telephone"Efficiency" is a two edged sword.
[4 Khz wide] channels than analog technology - for the same spectrum width. This even with the steep-sided filters and SSB technology.
Since the input and output need to be in analog form, I find digital's claim very unintuitive -- almost doubting it.
Can someone offer an intuitive explanation ?
I guess a 4 HHz bandwidth telco signal contains a lot of
redundancy which is not needed to convey the inteligence ?
Speech can even be transmitted as a sequence of 'predetermined
sylables' - what are they called again ?
So it seems to me that the improvement over analog methods
can't be acheived merely by 'modeming', which would only add
entropy. But once it's in the digital format, standard compression
[by removing redundancy] can make for more efficiency ?
Thanks for any info,
== Chris Glur.
If you want to apply efficiency to some existing technology you have to make allowances. If you want to implement something ssssoooo efficient that nobody can use it, you are on your own.
If you know any "old-timers" in radio amateurs club ask them when 100Hz accurate Morse code became popular, it was when TX-RX equipment advanced to this kind of accuracy.
So IT is about transfering info, and as much as possible on existing channels and in this context digitasation of info is "efficient".
Have fun
Stanislaw
Slack user from Ulladulla.
.
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