Digital noise

When data are transmitted, or indeed handled at all, a certain amount of noise enters into the signal. This can have several causes: data transmitted by radio may be received inaccurately, suffer interference from other radio sources, or pick up background radio noise from the rest of the universe. Microphones pick up everything—signal as well as background noise—without discriminating between signal and noise, so when audio is encoded digitally, it already includes noise.

Electric pulses being sent via wires are attenuated by the resistance of the wire, and changed by its capacitance or inductance. Temperature variations can increase or reduce these effects. While digital transmissions are also degraded, slight variations do not matter since they are ignored when the signal is received. With an analog signal, variances cannot be distinguished from the signal and so are a kind of distortion. In a digital signal, similar variances will not matter, as any signal close enough to a particular value will be interpreted as that value. Care must be taken to avoid noise and distortion when connecting digital and analog systems, but more when using analog systems.

Digital technology helping dental patients

(New York-WABC, March 29, 2007) - Digital technology is helping patients in the dentist office. Mainly, it's helping them envision better teeth.

With the help of digital photos and dental x-rays, one dentist is helping patients who may be facing thousands of dollars worth of dental work. He's showing them how they'll look after all that time and money.

White, shiny and straight. If you want a better smile or better teeth, now you can see how dental work will look before you get the treatment.

Dentist Steven Feldman has developed a new technology that can help you get the teeth you want. XCPT converts X-rays and digital photos into computer-generated images, so patients can see what their dental work will look like.

"Patients were more accepting of what their issues were and they were accepting of our recommendations, which was really nice. It was a good feeling," Dr. Feldman said

Take Gary Trombley. He suffers from severe decay. But before having surgery, he gets to see what will happen.

"I don't comprehend it as well unless I can see it and hear it, so it really helps that way," he said.

Fifty two-year-old Bob Dennison not only sees what's wrong on his x-rays, with a digital photo, Dr. Feldman shows Dennison how he can change his appearance.

"A picture is worth a 1000 words," Dennison said.

Doug Mann is six months into a nine-month plan to fix his teeth. The XCPT software gave him the confidence to do it.

"You know you have a problem. Now you see the problem. Now you understand what he has to do," he said.

And with doctor and patient on the same page, they'll both be smiling in the end.

There are about 150 dental offices that are testing the software. It's also in use to teach dental students the before and after of their work.

The cost of the software is about $3500, and doctors typically don't charge their patients any extra for using it.