Handouts

EE 163B

1. Sample eye diagrams for raised-cosine pulses: 0% and 100% excess bandwidth, 4-11-02
2. Effect of channel dispersion on the eye diagram, 4-11-02
3. The whitened matched filter channel model, 4-15-02
4. Sample solved problems, 4-29-02
5. Midterm review notes, 5-2-02
6. L.J. Cimini, Jr. and Y. Li, "Orthogonal frequency division multiplexing for wireless channels".
7. J.A.C. Bingham, "Multicarrier modulation for data transmission: an idea whose time has come", IEEE Commun. Mag., vol. 28, pp. 5-14, 1990.
8. H. Sari, G. Karam, and I. Jeanclaude, "Transmission techniques for digital terrestrial TV broadcasting", IEEE Commun. Mag., vol. 33, no. 2, pp. 100-109, Feb. 1995.

Matlab files and demos

1. 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.

2. 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.

3. 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.

4. 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.

5. Adaptive equalization:
   • Download and run zeroforcing.m - this is a zero-forcing equalizer with no noise. Change the channel time constant tau in the program. Notice how the equalizer "opens the eye" perfectly.
   • Download and run zeroforcing_noise.m - this is a zero-forcing equalizer with additive noise. Notice that the equalizer appears to amplify the noise.
   • Download and run wiener_equalizer.m - this is a Wiener filter equalizer with additive noise.
   • Download and run lms_equalizer.m - this is an adaptive equalizer using the LMS algorithm.

EE 163A

1. A little thought experiment, 1-10-02
2. Notes on $\pi$/4-QPSK, 1-28-02
3. Midterm review notes, ©IDM/2001, 2-7-02
4. Spectral efficiency chart
5. Final review notes, ©IDM/2001, 3-7-02