** EE 163B**

- Sample eye diagrams for raised-cosine pulses: 0% and 100% excess bandwidth
- Effect of channel dispersion on the eye diagram
- The whitened matched filter channel model
- Demo movie of the Viterbi algorithm
- Interactive Viterbi algorithm

** Matlab files and demos**

- DSB suppressed carrier demodulation using a Costas loop:
- Download
`costasloop_init.m`and`costasloop_demo.mdl`. - Start Matlab, type
`costasloop_init`, hit return, and then run`costasloop_demo`at the prompt.

- Download
- Intersymbol interference:
- Download and run
`raisedcosine_demo.mdl`. - Change the
`filter rolloff factor`("beta") in the`R-C filter`block and see the results. - Observe the eye diagram for different values of beta. Is the eye "more open" when beta = 1? Can you see much less sensitivity to errors in the sampling times when beta is close to 1?
- Try increasing the noise level by changing
`sigma`in the`Rayl N`block from 0.001 to 0.1. See how the scatter diagram smears, and also see the effect on the eye diagram.

- Download and run

** EE 163A**

** Matlab files and demos**

- Quantization effects:
- Download and run
`quantization_demo.m`. - Change the number of bits to
*R*= 7, 6, 5, 4, 3, 2, 1 and listen to the output. You will notice that at a certain quantization level and signal-to-quantization-noise ratio the noise due to quantization becomes audible. - You can also click below to hear the effects of quantization (to
*R*bits or*L*= 2^{R}+ 1 levels) without running the program above: Original, 7 bits, 6 bits, 5 bits, 4 bits, 3 bits, 2 bits, 1 bit.

- Download and run
- Matched filtering:
- Download and run
`matchedfilter.m`. - Note that best performance is obtained with rectangular matched filtering of the rectangular pulse.
- Run the program repeatedly until the point where matched filtering of the triangular pulse appears to be better than rectangular filtering.
- Change the noise amplitude and observe the effects.
- Download
`mc_matchedfilter.m`- this simulates the detection performance of various filters over 10,000 runs.

- Download and run