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Anyone know about signals?

PostPosted: Thu Jun 09, 2005 2:30 pm
by Liam
Sorry, I couldn't find a great place to post this....so I'll lump it here.

Anyone knows how analogue signals are actually generated (from voice, and for transmitting)? Obviously digital signals are electrical pulses to represent different values...but analogue? I really should know this, but I haven't been over it in a long while.

Cheers! I'm sure someone can give me a response!   :-[

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 2:34 pm
by ozzy72
Do you mean converted into digital signals for transmission (sampling) Liam?

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 2:37 pm
by Liam
No, sorry I didn't make myself too clear.

Obviousy Digital signals are artificial, and Analog are (theortically) natural...is there a good way to say how, from a persons voice, the noise is made? Like from vibrations etc? I guess electrical pulses can also be involved from microphones?

Cheers!

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 2:47 pm
by ozzy72
Well a microphone would have a diagphram in it that vibrates to the sound of the persons voice generating electrical signals. These look like waves if seen on an oscilloscope.
The problem with transmitting analogue is signal deterioration, hence why most signals are sampled and made digital these days as it is easier to boost them without losing quality.

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 2:49 pm
by Fozzer
Digital signals are transmitted by varying electrical pulses.
These then have to be converted into analogue signals for the human ear to be interpreted as sound pressures.
Your modern telephone has a digital to analogue system, first to transmit the signals and then convert them to be heard by the recipient.
Analogue signals are transmitted by varying electrical frequencies...(wave-forms), and reach the human ear as sound pressures.

Early radio transmissions were always analogue signals.

Sound travels through air as sound pressure waves...
...in space, no-one can hear you scream..!!

..Here endeth the first lesson...;)...!

LOL...!

Paul.

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 2:50 pm
by Liam
Thanks for that, I think that gives me a good place to start. Now my task is to chat as much BS about it as possible!  ;D

If anyone else can think of anything else constructive to add then it's much appreciated.

Thanks again Ozzy! (There was me thinking your were just a stuntman...)

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 2:56 pm
by Fozzer

If anyone else can think of anything else constructive to add then it's much appreciated.



I wouldn't bank on it....
...not from the mad lot at Simviation, anyway... ;)....!

Paul.... ;)...!

What frequency does a Vibrator vibrate at...?.... ;)... ;D...!
LOL...!

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 3:03 pm
by Liam
What frequency does a Vibrator vibrate at...?.... ;)... ;D...!
LOL...!


I know most would be happy with this digital representation:

111111111111111111111111....  ;D

Nice one Paul.

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 3:20 pm
by Jared
Oh geez, PETE! We need some medication stat! ;)

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 3:25 pm
by C
Maybe I'll dig my telecommunications notes out this weekend if I can find them (don't bank on it). Did alot about it in the second year at uni...


Charlie

edit - here's a brief explantion here...

http://eserver.bell.ac.uk/mirrors/dc100www/dc_006.htm

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 3:27 pm
by Liam
That would be brilliant!!  :)

Re: Anyone know about signals?

PostPosted: Thu Jun 09, 2005 7:24 pm
by Felix/FFDS
I can't help but get a good chuckle.

My academic background is electrical engineering, communications - as in telephony.  In my professional youth, I was even in charge of maintenance for the microwave radio systems in the communications department of a large company....  Back then, we were installing the first "digital" switching systems, an incredible improvement over the hard-wired cross-bar switching systems of the period

Now everything's digital ....

To me, digital is a piano's note.... analog is a a violin's note....  the faster you strike a piano's keys, the closer you get to the violin's sound.

Re: Anyone know about signal

PostPosted: Fri Jun 10, 2005 1:21 am
by H
I can't help but get a good chuckle.

.... To me, digital is a piano's note.... analog is a a violin's note....  the faster you strike a piano's keys, the closer you get to the violin's sound.



Is this going from keyed-in to strung-out? :)

Where the subject of aging from infancy is brought up in the article http://eserver.bell.ac.uk/mirrors/dc100www/dc_006.htm why isn't it mentioned that our ear diaphragms enlarge with age which naturally contributes to our lowering hearing range (frequency- wise); not really the same as the hardening of the bones. Size does matter and, in this case, with lower expectations :-[.