Prev: Signals on FFT bins, and Windowing
Next: Announcing AjarDSP - an open source VLIW DSP
From: glen herrmannsfeldt on 20 Jul 2010 19:29
The term 'broadband' is commonly used to describe high
speed networking systems. There is a question in
comp.protocols.tcp-ip related to that term. Does
the term make any sense?

As far as I understand it, broadband originated in terms
of television signals, where the signal bandwidth is a
signfificant fraction of the carrier (or maybe center)
frequency. That complicates filter design, and so is
an important part of system design. For audio/radio,
the bandwidth is a much smaller fraction of the carrier.

Now, does this distinction make any sense in terms
of digital network communication? It seems to me that
it doesn't. (Though it does seem that cable modem
channels are still designed around the 6MHz TV channel
bandwidth.)

-- glen
From: Tim Wescott on 20 Jul 2010 20:15
On 07/20/2010 04:29 PM, glen herrmannsfeldt wrote:
> The term 'broadband' is commonly used to describe high
> speed networking systems. There is a question in
> comp.protocols.tcp-ip related to that term. Does
> the term make any sense?
>
> As far as I understand it, broadband originated in terms
> of television signals, where the signal bandwidth is a
> signfificant fraction of the carrier (or maybe center)
> frequency. That complicates filter design, and so is
> an important part of system design. For audio/radio,
> the bandwidth is a much smaller fraction of the carrier.
>
> Now, does this distinction make any sense in terms
> of digital network communication? It seems to me that
> it doesn't. (Though it does seem that cable modem
> channels are still designed around the 6MHz TV channel
> bandwidth.)

I think that "broadband" in the internet sense means "way faster than
you can get over telephone lines". So my cable modem delivers
"broadband" internet to me, but whether it is really truly broadband in
the radio receiver sense, or narrowband, or even baseband, makes no
difference to how quickly I can download, nor what nonsense my cable
company's marketing folks will blather at me.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
From: steveu on 20 Jul 2010 20:46
>The term 'broadband' is commonly used to describe high
>speed networking systems. There is a question in
>comp.protocols.tcp-ip related to that term. Does
>the term make any sense?
>
>As far as I understand it, broadband originated in terms
>of television signals, where the signal bandwidth is a
>signfificant fraction of the carrier (or maybe center)
>frequency. That complicates filter design, and so is
>an important part of system design. For audio/radio,
>the bandwidth is a much smaller fraction of the carrier.
>
>Now, does this distinction make any sense in terms
>of digital network communication? It seems to me that
>it doesn't. (Though it does seem that cable modem
>channels are still designed around the 6MHz TV channel
>bandwidth.)

Once a technical term has been picked up by popular culture, why would you
expect to find any meaning in it at all?

Steve

From: glen herrmannsfeldt on 21 Jul 2010 00:53
steveu <steveu(a)n_o_s_p_a_m.coppice.org> wrote:
(snip on broadband)

>>Now, does this distinction make any sense in terms
>>of digital network communication? It seems to me that
>>it doesn't. (Though it does seem that cable modem
>>channels are still designed around the 6MHz TV channel
>>bandwidth.)

> Once a technical term has been picked up by popular culture,
> why would you expect to find any meaning in it at all?

Well, there is that.

Then there is Wi-fi which doesn't seem to have any meaning
at all in the technical sense.

thanks,

-- glen
From: Eric Jacobsen on 23 Jul 2010 19:25
On Wed, 21 Jul 2010 04:53:47 +0000 (UTC), glen herrmannsfeldt
<gah(a)ugcs.caltech.edu> wrote:

>steveu <steveu(a)n_o_s_p_a_m.coppice.org> wrote:
>(snip on broadband)
>
>>>Now, does this distinction make any sense in terms
>>>of digital network communication? It seems to me that
>>>it doesn't. (Though it does seem that cable modem
>>>channels are still designed around the 6MHz TV channel
>>>bandwidth.)
>
>> Once a technical term has been picked up by popular culture,
>> why would you expect to find any meaning in it at all?
>
>Well, there is that.
>
>Then there is Wi-fi which doesn't seem to have any meaning
>at all in the technical sense.
>
>thanks,
>
>-- glen



As has been mentioned, I think "broadband" has gone the way of being
whatever people want it to mean.

However, Ultrawideband has, at least for the time being, a specific
definition, which at the moment seems to be >500MHz BW or >20% of the
carrier frequency. So, broadband could arguably be something between
that and "narrowband", although I'm not sure "narrowband" has a
specific interpretation. ;)

FWIW, Wi-Fi is the trademarked name used by the Wi-Fi Alliance, an
industry consortium that manages compliance with the Wi-Fi
specifications, which are essentially the 802.11 air interface
standards. People may use it to mean wireless LAN generically, which
is probably fine with the Wi-Fi people since that's what they exist to
promote.

http://www.wi-fi.org/


Eric Jacobsen
Minister of Algorithms
Abineau Communications
http://www.abineau.com
 |  Next  |  Last
Pages: 1 2
Prev: Signals on FFT bins, and Windowing
Next: Announcing AjarDSP - an open source VLIW DSP