Przemek Klosowski wrote on 7/17/2016 9:26 AM:
On Fri, 15 Jul 2016 13:17:48 -0400, BPVeW*ｉｇｈｔｙ Ｗａｎｎａｂｅ
fZSSO wrote:
Digital cellphone system is almost like digital TV. You either get it
100% or you don't get it at all, because the signals are all in ones and
zeros.
That ain't right---you can see how it really works with progressive GIFs.
Basically, you send the crude approximation of your signal (image in this
case) first, and then if you have bandwidth/time/money/patience you show
more detail. A good example is he
https://blog.codinghorror.com/content/images/
uploads/2005/12/6a0120a85dcdae970b0128776fcadb970c-pi.gif
You could think of this as using very low bandwidth aka low bitrate
connection in the beginning (sending just few 'bits' of the image), and
then increasing the number of sent bits per unit time to get more detail.
Ed was talking about the phone companies using adaptive audio bitrate,
which is how the phone company manages their limited aggregate cell tower
bandwidth. They basically can serve small number of customers at high
bitrate that gives very good sound quality. If, however, they get a lot
of cellphones trying to use an oversubscribed tower, they run out of
bandwidth. They COULD drop the call (drop from 100% to nothing at all, as
you say), but the customers tend to complain loudly about that.
Instead, the phone company came up with a brilliant idea: they switch
everyone to a low, crappy bitrate, so they can handle a lot of cellphones
at lower quality. It's much harder for the customers to quantify their
complaints now ("maybe momma is just mumbling"). Geniuses.
You are talking about "digitizing" voice or video.
I am talking about the "transmission mode" of analogue cellphone and
digital cellphone, and the equivalent technology of digital TV and
analogue TV.
Canada has phased out analogue TV broadcast a few years ago. All TV
broadcast over the airwaves are now digital in Canada.
https://en.wikipedia.org/wiki/Digital_terrestrial_television_in_Canada
It is true that when you are transmitting in digital form, the signals
are in ones and zeros, so that you either get it clearly or you don't
get it at all.
Analog Versus Digital TV: What's the Difference?
http://www.quepublishing.com/articles/article.aspx?p=1245329&seqNum=2
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How Digital Television Works
DTV is more advanced than the older analog technology. Unlike analog
television, which uses a continuously variable signal, a digital
broadcast converts the programming into a stream of binary on/off
bitssequences of 0s and 1s. This is the same way that computers store
information in data files; each bit represents a small part of the
picture, and all the bits combine to reproduce the original picture.
The primary advantage of digital broadcasting is that these binary bits
recombine to reproduce an exact copy of the original material. The
picture and sound received from a digital transmission are always
identical to the original source.
Even better, over-the-air digital signals dont weaken over distance, as
analog signals do. As long as the signal can be received, the picture is
perfect, with no degradation or ghosting. Because digital signals are
composed of binary bits, a 1 is always a 1, and a 0 is always a 0. There
is no fuzziness or snow in the picture, no ghosts caused by interference.
In addition, digital is a more efficient technology. A digital
transmission requires less bandwidth than does a similar analog
broadcast; this lets local television stations broadcast two, three, or
even four digital channels in the space of a single analog channel. This
multicasting technology means youll receive more variety in
programming from your local stationsall delivered with superior digital
quality.
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