Week of December 13, 2010
- 12/17/10: For Quiz 3 solutions, click on the "On-line grades"
link on the left to get to Quiz3Solutions.pdf.
Quiz 3 stats: n=157, avg=71.31, stddev=13.27.
- 12/17/10: Total score stats: n=157, avg=85.4, stddev=8.33.
Your points should be visible on the course web site. Please come to
32-G944 (Sheila Marian's desk) to pick up your quiz between 8.30 am -
3 pm on most working days. We will file the grades with the registrar
on Monday, after which you can get it from websis. Please do not
directly ask us what your final grade was.
- 12/14/10: Added Addendum to Recitation 16 (how modulation operates over DTFS).
- 12/12/10: All grades except the final quiz are in for all 157
students. The mean is about 71/80, the median is around 72.9/80, and
the standard deviation is 6.52.
- Solutions to the problems at the end of Chapters 17-22 and
online PSets 7-9 are available if you click on "On-line grades" on the
left panel.
- So what do you need to know from Lectures 12 through 16 for
Quiz 3? The answer is:
- Continuous frequency vs. Discrete frequency.
- Discrete-Time Fourier Series (DTFS): definition and basic properties (N-periodic nature, time-domain interpretations of X[0] and X[N/2], etc.), calculating the coefficients in simple cases (including just "pattern matching"), plotting them (manipulating between k, Omega_k, and f_k for the horizontal axis), and knowing what bandwidth is.
- How a channel's frequency response affects Fourier coeffs, specifically in the case of a simple delay.
- Modulation/Demodulation: drawing spectra associated with the stages of modulation/demodulation, figuring out carrier and demodulation frequencies to shift spectra to desired locations or avoid overlap.
- Filtering to band-limit a signal or to pass only desired frequency bands and eliminate others.
We encourage you to study the problem set for Lab 7, and the review
problems on this material that have been posted to the web site, as
well as the lecture notes/slides for Lectures 14 through 16 (these
lectures build on the concepts described in Lectures 12 and 13). You
may also wish to consult the recitation notes from Prof. Verghese on
Recitations 14-16 that are on the web site, if the other materials
aren't sufficient.
Finally, please plan your study time evenly -- the final quiz has
several topics, and the coverage will be balanced. We expect
*roughly* 20% of the points on the material listed above. We expect
*roughly* 20% on source coding (information & entropy, Huffman coding,
LZW). The remaining *roughly* 60% will be on switches, network
delays, queues/Little's law; routing protocols (link-state and
distance-vector); and reliable transport protocols (stop-and-wait,
sliding windows, round-trip time estimation, timeouts). These rough
percentages are subject to change, but we don't expect the changes from
these percentages to be large.
- Quiz 3 prep: We have some past quizzes for you to check out.
Note, however, that the material for our quiz is somewhat different:
digital modulation is included, but not MAC protocols. The practice
quizzes from recent previous terms don't have modulation, but cover
MAC protocols, so please keep that in mind.
- Please take a moment to fill out the HKN Survey.
We'd very much like get your comments on the course!
- Quiz #3 information:
- Time: Thursday, 12/16, 1:30pm - 4:30pm.
- Location: Johnson Track.
- Coverage: From L12 through the end of the term (DTFS & modulation; multi-hop networks, delays, and switching; routing; transport; source coding).
- What you can bring: one "8.5x11" cribsheet, no calculators.
- For those still confused about how final grades are calculated,
please check out the "Course info" link on the left. This information
has been in place since Day 1: 50% for the labs (5% each), 50% for
the quizzes (Quizzes 1 and 2 are 15% each; Quiz 3 is 20%.
- This week's to-do list:
- Thursday, December 16: Quiz 3, 1.30 pm - 4.30 pm, Johnson
- Next week's to-do list: Enjoy your break!
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