VAB 
ID #

VAB TITLE

Type of VAB

Description of VAB

6-1

Aliasing Wheel Movies

Watch

6-2

Aliased Sinusoids; Speech and Music in the Analog World

The following signals have been sampled and then reconstructed from their samples, assuming the sampling rates indicated. The results were recorded onto the VAB platform. Listen to these signals in your Hyperception/VABHS/sounds directory to discover what the results of aliasing sound like in the analog world!

Winamp should open these .wav files. Choose a visualization that will allow you to see as well as hear the differences. Make sure your headphones are plugged into the speakers which are jacked into the PC sound card output port.

Location for files is C:\Program Files\Hyperception\VABHS\Sounds\

1. demo_fs1016_4k8.wav
2. demo_g726_32k.wav
3. demo_g728_16k.wav
4. demo_is54_8k.wav
5. demo_melp_2k4.wav
 

Copy the sound file names at left. Open up an email. Add a brief description of any difference you heard (and saw!) as you played these sounds). Email to Mr. Rummel

6-3

Quantization and Clipping

Explore

Students see and hear the effects of quantization.

Listen to:

Speech coded at 7 bits, 5 bits, 3 bits, and 1 bit per sample. The corresponding SNRs are 42, 30, 18, and 6 dB, respectively.

Music coded at 16, 13, 10, 7, 4, and 1 bit per sample. The corresponding SNRs are 96, 78, 60, 42, 24, and 6 dB, respectively.

Can you hear why we need to avoid aliasing?

6-4

Quantization Noise

Students compare the quantization noise to the SNR lab noise (#5).

Due Tuesday, 2-26 at end of class.