Sampling, Quantization and Reconstruction
This applet demonstrates the effects of both sampling rate and quantization.
The top graph shows the original analog signal. The second graph shows the samples
of the original signal. The next two graphs show two forms of the reconstructed
quantized signal.Graph three represents a simple reconstruction where the quantized
value isheld constant from one sample time to the next. This is called "zero
order hold." Graph four shows the effect of a much more appropriate type of
reconstruction, where the sampled and quantized signal is transmitted through
a properly designed filter.
The user can choose the signal to process, the sampling rate, and the number
of bits used to perform the quantization.
The default value for sampling rate at start-up is 500 Hz, and can be varied
from 30Hz to 20 kHz. The number of bits of quantization may be varied from one
to seven. Recall that one bit of quantization corresponds to two amplitude levels,
two bits corresponds to four levels, etc.
For a given signal, try various combinations of sampling rates and numbers
of quantization bits to see the effects on the two forms of reconstructed signals.