Unfortunately, Lab 1 does not explicitly specify the content or format of the Pre-Lab.
Please submit the answers to the questions in the pre-lab section of the lab as a PDF file. Include:
Lab 2 is taking longer to complete than expected so we will allow two weeks to complete it. The deadline for the report has been extended by one week. The pre-lab is still due before the first last session.
A slightly revised version of the lab3 handout is available on-line.
See the Content/Software section of the course web site for a partial lab3 solution. See Content/Reference Material section for the 'scope and VISA manuals.
A 500ms delay before each measurement does not give reliable results after a scale change. Please use a 1000ms (1s) delay.
Out-of-range values (e.g. values >1E9) indicate measurement errors and should not be written to the file (i.e. to stdout) and should not be used to adjust the vertical and horizontal scaling. But they should be written to stderr so you can see what is happening.
The initial settings in the sample C solution are appropriate for a frequency of 100 Hz and a voltage of about 4 Vpp. You should start your measurements at this frequency and input level and go up in frequency from there.
The 'scope may not be able to measure the frequency and/or voltage if the vertical and/or horizontal scaling are too far off. If this happens, change the signal generator frequency and voltage back to values that the 'scope can measure and continue from that point. If the 'scope settings get set to extreme values you may have to restart the measurement.
Since your response will be plotted on a logarithmic frequency axis try to space the sampled frequencies appropriately. For example, use approximately the same number of sample points in each decade-wide signal generator frequency range rather than taking one sample point per constant frequency interval (not every 1kHz for example).
Some of the channel simulator boards have broken PCB traces resulting in no output. Check yours.
Just a reminder: since everyone completed the lab last week there will be no lab this Monday (September 29).
At a minimum, your program listings should be printed in a monospaced font (each character is the same width), not wrapped and single line spacing.
You can use Notepad++ to "pretty print" your source code. Open your source code file with Notepad++, select the text you want to copy, use the menu item Plugins > NppExport > Copy RTF to clipboard and paste with formatting into your document. This should copy over the formatting used in Notepadd++ to your word processor.
The C statment
for(e1;e2;e3){
...
}
is exactly equivalent to:
e1 ;
while (e2) {
...
e3 ;
}
We will do Lab 4 on October 27 (i.e. following Lab 5). See dropbox for Pre-Lab report due date.
If your results show the error rate dropping to 0 after a specific threshold value then you may have used the rand() function (which generates uniformly distributed noise) rather than the randn() function which generates normally-distributed (Gaussian) noise. You can check by reading the lab7.dat file with noise samples back into Matlab and plotting the histogram of the values:
f=fopen('lab7.dat','r')
x=fread(f,1e6,'int16');
hist(x)
If your histogram consists of only positive values and all bins have about the same count then you probably used rand() instead of randn() to generate the noise. In this case the probability of error will decrease linearly with increasing threshold voltage. You can either re-do the measurements or use a different equation to compute the predicted BER and plot the BER curve on a linear-linear graph.
Here are two examples of the first 100 samples of the noise waveform. One is uniformly-distributed and the other is normally-distributed. Can you tell which one is which?
The final exam for ELEX 4340 has been scheduled for Wednesday January 7th in SW1-2019 from 0800-1100. Please verify.
Tentative schedule for remainder of term:
| Week of | Lectures | Lab |
|---|---|---|
| Dec 1 | 14 (ARQ), 15 (Ethernet) | Lab 8 (Modulator) |
| Dec 8 | 15, 16 (IP) | Lab 9 (Scrambler) |
| Dec 15 | 16, review | Lab 10 (Wireshark) |
I was asked to move the Tuesday lecture to 1:30 to allow the final-year presentations to begin at 2:30.
I thought we had agreed to cancel the lecture but some students said that they had been told that the class would go ahead.
As a compromise, I will start the lecture at 1:30 but end at 2PM in case some students were counting on extra time to set up. The material to be covered in this lecture (security) will not be on the exam.
Everything except the final exam has been marked. Please check that your marks were correctly recorded and computed by looking at the marks file under Content / Course Information. You'll need the password that was distributed in class to retrieve your marks. The overall lab mark is computed from your 9 best lab marks. Let me know if there are any questions or issues.
Congratulations, everyone passed.
The final exam marks ranged from 72% to 97% with an average of 89% and a median of 93%. The solutions and marking scheme have been posted.
The tentative final marks for the course range from 77% to 97% with an average of 88% and a median of 89%.
These marks are subject to change.
Please check your marks and let me know of any marks that were incorrectly recorded or computed.
Thanks!