MTD2 class 9

In class

Review and discuss rough movie edits.
Digital Theory 2
- Listen to Beethoven examples (Sample Rate and Bit Depth)
- Discuss Digital Errors
- Look at sampling circuit
Quiz Three Next
- The quiz will cover week digital theory 1 Audio Digitization 2 and chapter 3 from Sound Design for Interactive Multimedia

Three types of digital errors

Quantization Error - Difference between actual analog value and quantized digital value
Aliasing - Undersampling
Jitter - Time errors

Quantization

Quantization Definition

Quantization Signal Processing

Discrete levels based on the number of bits

Analogy

Analog is like a bucket of water while digital is like a bucket of ball bearings. Analog has an infinite resolution while a digital system can only resolve thins to finite values.

"...if sheets of typing paper were stacked 22 feet, a single sheet of paper would represent one quantization level in a 16-bit system. In a 20-bit system, the stack would reach 349 feet. In a 24-bit system, the stack would tower 5592 feet in height - over a mile high." -Principals of Digital Audio, Ken C. Pohlmann McGraw Hill

The more bits you have the more dynamic range you have. Each bit is equal to approximately 6 more dB. 16 dB s about 120 dB of dynamic range.

Quantization Error

Quantization_error

Quantization error = the difference between the actual analog value and the quantized digital value.

The less bits that you have to quantize a signal the larger the quantization error will be. More Bits = Less Quantization Error

Quantization Error is also known as Signal

Dither

Dither = noise added to signal

addition of a small amount of white noise to the signal to reduce signal-to-error distortion ...also aid in processing and bit depth conversion... see dither article

Audio Dither Example

READ dither Article

http://www.digido.com/ditheressay.html