When emulating an analogue signal with a digital system you inevitably run into the "squaring the circle" problem. No matter how good your D/A or A/D converters you will only be able to come CLOSE to replicating the original analogue signal.

kind of like shooting movies on DV and releasing them on film because its a "cool" new way to make "films" and cause its cheaper.

I took Algebra I and Algebra II in High School but instead of taking Trig. and Calc. I took Geometry. After that, in college i took a couple of elementary Statistics classes. Is this something I would have learned if I had taken the other track? Or, is this something completely different?

Clue me in!

I know a guy who i graduated from college with who made a pretty good quality 5 part movie (15 minutes each since it was run as a television series for our school's cable station). Our school uses mini DV cameras which produce really good video images on a TV screen, and based on this, cost, and efficiency, he said that when he starts making big movies he goig to use all digital.

Ken is right. Digital audio kicks ass. Most of the time. I don't really care for the digital EQing scheme in the latest processors from Sony and Dolby. There is just no way that you can achieve the same exact curve with digital EQ as with an analog EQ each and every single time. But that's a different story.

The point I am trying to make is that people automatically associate the word "digital" with "the best it can possibly be". Have you seen ads for the latest TV hard disc recorders, etc? They advertise that they record up to 4 billion hours (or so) in "full digital quality". Well, since it's digital it must kick the living hell out of VHS! Nope. When you see the 4 billion hour low quality mode it's not even as good as Video CD. And Video CD is noticably worse than VHS (even worse than VHS in EP if you ask me, just due to the artifacting). MPEG sucks (MPEG 2 is better, but I can still see lots of artifacts on DVDs, especially in dark scenes). But its digital, right? So no matter how bad it is, it's still waaaay better than any analog recording device!

"Digital" and "Digital Done Right" are two completely different things! Don't fall for a cinema processor just 'cause it says "digital processing" in the ads. That doesn't mean it will sound good. Audition it for yourself first!

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However, it is not true, as Ken stated, that the waveform will be reproduced exactly. Take a sine wave sampled at exactly twice its frequency. Try it yourself -- instead of a curvy sine wave, you'll get a triangle wave. At 22.05 KHz, you'd be hard-pressed to notice the difference. Hook up a function generator to a set of headphones and compare low-frequency sine and triangle waves, though, and you'll notice a distinct difference.

The Nyquist Theorem ensures an accurate epresentation of the signal, but "squaring the circle" (or in this case, triangling the sine) always occurs when trying to represent a continuous input discretely.

Any digital camera or projection system that uses a fixed array of pixels may suffer aliasing unless a low-pass filter or defocusing are used to minimize the risk of interference.

Here are some links:
http://www.kodak.com/US/en/digital/dlc/
http://www.spie.org/web/meetings/programs/or97/sc/or97_sc22.html
http://www.imagingspectrum.com/portraitcomparison.htm
http://www.kodak.com/cluster/global/en/service/faqs/faq1082.shtml

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Steve,
Give a listen to the Panastereo Processor with the new SR card. You'll be very surprised at how much better it sounds!

Joe said
"Too many people are wooed by the word "digital" these days. Just because it's digital doesn't mean it's good.

Joe, you hit the nail on the head!
Take the Panastero Processor for instance. Blows em all out of the water by a long shot.

IMHO, Dolby should have and could have lowered the price of the CP650 substantially as it is far cheaper to mass produce than the 500 was.
Mark @ GTS

A properly designed A/D and D/A conversion process does not simply sample a waveform, and then reconstruct the samples by ordinary linear interpolation (connect the dots). This would require a tremendously high sample rate to adequately reproduce the input signal. There are 'other things' that go along with following Nyquists theorem to stay out of trouble. One of those things is to low pass the input signal at the half-sampling frequency. This is also know as an anti-aliasing filter. Another one of 'those things' is to provide an (ideal) low pass reconstruction filter at the output, also known as a smoothing filter. This filter will have a sin(x)/x impulse response. When samples of the bandlimited input signal (remember the low pass filter at the input?) are processed with this impulse response, the input signal will be exactly reproduced...there's more too...

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

SDR is here to stay. So Dolby will rule.
even ads are srd these days (even with the bad error rates)
I prefer DTS as it has less drop outs.