ping: Jim Thompson

Hello Steve,

Nothing wrong with it. But on a noisy channel that contains some radio links it might not cut it. Why settle for 12bits when you can buy a uC with a 16bit converter at around the same budget? It's not advertised much for some reason but the MSP430F2013 contains a 16bitter and can be had between $1.50 and $2.00 depending on volume. I believe its prime market is power metering and that probably doesn't require much advertising.

Regards, Joerg

No, it's dynamic range is 48dB -- but only in the sense that you can listen to something, then the same thing 48dB down. You _can't_ listen to one signal at max amplitude at the same time you're hearing another one, undistorted, 48dB down.

This is fun. I'm waiting for the response to this post that starts out "No, ..."

--

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

Posting from Google?  See http://cfaj.freeshell.org/google/

No, [ :-) ], you can't ordinarily do that anyway. Masking.

Jerry

--
Engineering is the art of making what you want from things you can get.
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Only if the bits are being used to provide a voice channel, as contrasted to a 64 kbit/s digital channel or concatinated digital channels.

Don

No. The SDR of u-law and a-law is a lot less than 48dB. It is more like

30dB. 48dB would be the range of an 8 bit number. The telephone network kinda has 5 bit numbers and 3 bit exponents.

Steve

Let me express this more technically........ You are terribly mistaken.

However, program channels that are better than the C-message weighted ones, use bits from multiple channels to achieve a better response, but the numbers of these is miniscule compared to the message network.

Could you possibly be thinking of a ADPCM application used in private networks?

Don

When you send bits, you send bits. The converter used for sending voice has 12 bits. (It will have 8 outputs if the pseudo-log converter is integrated with it.)

Jerry

--
Dr. Bettelheim, when I knit, I knit; when I masturbate, I masturbate.
                  --   Helen Krasnow, as a student at Barnard College.
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Oh. Dangit. How'd I get 12 * 6 = 48? Must be the New Math.

--

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

Posting from Google?  See http://cfaj.freeshell.org/google/

"Forty-eight? How did forty-eight get into it?" I hear you cry. Well, forty-eight is 6*8, don't you see? (Well, you ask a silly question, and you get a silly answer.)

Apologies to Tom Lehrer :-)

Steve

Well, I think that's where it came from, too -- but it was supposed to be 12 * 6. My kid does that. I try to impress upon him the importance of showing your work for just that reason. Still, he (and I) persist in doing things in our heads with little errors.

--

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

Posting from Google?  See http://cfaj.freeshell.org/google/

Well what is really fun to show is how to improperly reduce a fraction and still get the right result

16 1

--- = ---

64 4

just cancel out the sixes.

Try it with

19

--
95

cancel the nines and you get  1/5

Of course the trick is there are four cases where this works when 2 digits 
are divided by two digits.

Clay

At the per channel level, the only place where more than 8 bits are used is in the exchange between the codec and channel units, where 14 bits are used to set the PAM polarity, Cord, and level within the cord, switches for the codec.

Don

Your words have an intriguing surreal quality. :-)

Steve

And yours appear to be mindless.

Av>

domain

convert

to

OK alligator breath, explain v.90 modems.

--
JosephKK
Gegen dummheit kampfen die Gotter Selbst, vergebens.  
--Schiller

Well, skunk tail breath, what's that have to do with the current discussion, and why should I explain them?

Don

they

uses

contrasted

discussion,

You have been talking big, but have not shown me a good grasp of how Continuously Variable Slope Delta (CVSD) codec's work. You could really show me by explaining how they pack 56,000 bits/s down the voice telephone lines, through the D4 channel banks that does the analog/digital conversions at 56,000 bits/s with a CVSD and so on th the other end. I have been watching the CVSD's develop for over 30 years, and i followed all the way to 28800 baud modems. Some of the tricks necessary for 56000 baud interact in ways i do not fully understand yet. Enlighten us all please.

--
JosephKK
Gegen dummheit kampfen die Gotter Selbst, vergebens.  
--Schiller

"Continuously variable slope" is the key phrase... modulation AND demodulation are both adaptive to the change of slope rate.

That used to be well-explained in an old Motorola data book, but I can't seem to lay my hands on the correct manual right now.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

I have not been "talking big," but have simply been discussing fairly simple things about analog-PAM-PCM conversion in the telephone Network.

Regarding CVSD, I am not a modem person and really have no idea how it functions in a modem, other than what I can *guess* at from the definition.

The codec in the telephone network (Mu-law) is *not* a CVSD type.

Don