Marking Scheme
The items below were checked. One mark was assigned for each item
unless otherwise indicated. Deductions are shown in the comments.
Quizzes
Quiz 1
Q1
- correct bit rate
- correct information rate
- lowest data rate == information rate
information rate should not be rounded: -0
information rate is in bits/message: -0.5
each message is 2 bits: -0.5
retain more digits in your calculations: -0
you reversed the nybbles, not the bits: -1
Q2
- correct byte order
- correct bit order
Q3
- start and stop bits
- correct bit order
- correct bit values (and polarity)
- correct parity
- correct voltages and bit duration
Typical Comments:
wrong bit order: -1
missing start and/or stop bit: -1
missing/wrong parity bit: -1
voltages/time wrong or missing: -1
wrong bit polarity: -1
wrong number of bits: -1
Quiz 2
Q1: -1 mark per incorrect transition
Q2: -1 mark per extra or omitted byte
Q3: -1 mark per wrong answer
Quiz 3 (9)
Q1 (3)
- ISI-free symbol rate from bandwidth
- bits per symbol from number of levels
- correct answer
Typical Comments:
1 see solutions: -3
2 wrong symbol rate: -1
Q2 (1)
- correct answer
Typical Comments:
1 use difference if Eb/No in dB: -1
Q3 (2)
- use of Shanon capacity for AWGN
- correct answer
Typical Comments:
1 S/N should be in linear units: -1
2 no or wrong answer: -1
3 see solutions: -2
Q4 (3)
- one mark per correct answer
Labs
Pre-Lab 1 (3)
- Q1: square wave rms voltage
- Q4: frequency range for AC voltage on 20V range
- Q5(b): resolution for 12-bit ADC with 20V input range = 20V/4096
Lab 1 (6)
- cover page
- plots of samples
- three histograms
- three 'scope screen captures
- table of measurements
- correct explanation of discrepancies
Pre-Lab 2 (4)
- sum of digits
- table showing correct voltage levels for each bit
- voltage waveform
- correct sample period
Typical Comments:
The ratio of sampling rate to bit rate is specified in the lab notes: -1
Lab 2 (3)
- sum of digits in ID
- correct computation of sample period and sample rate
- screen capture of decoded waveform
Typical Comments:
missing/incorrect calculation of sample period and sample rate: -1
Pre-Lab 3 (2)
- levels
- connect AWG output to on a DTE
Typical Comments:
levels at the transmitter should be greater than +5 or less than -5: -1
on a DTE RxD (Receive Data) is the input: -1
lab asks for pin name, not number: -1
Lab 3 (3)
- Octave waveform plot
- 'scope screen capture with decoding showing name
- Teraterm screen capture
Pre-Lab 4 (3)
- rand return value (random numbers)
- > operator returns (0 and 1)
- . is the transpose operator (swaps rows & columns, result in [ 1 1 1 ; 0 0 0 ] )
Lab 4 (3)
- 3 scope screen captures
- one plot of three computed spectra in dB
- table of values with 4 values per line code (
Typical Comments:
1 missing or incorrect values in table: -0.5
Pre-Lab 5 (3)
- Q5: Rin=3 to 7 kOhm, Rout=300 Ohm
- Q6: slew rate = 3 typical to max 30 V/us (instantaneous)
- Q9: Rin = 1k * (10/(15-10)) = 2k
Typical Comments:
1 no answer: -1
2 math error: -1
Lab 5 (4)
- output voltage measurement: 1
- output impedance measurement: 1
- slew rate measurement screen capture & comparison to spec: 1
- input impedance measurement: 1
Typical Comments:
1 no comparison to specification: -0.5
2 missing measurement: -1
Lab 6 (2)
- descrambler schematic
- correct waveforms
Lab 7 (5)
- a spreadsheet (in the PDF)
- two flowgraphs
- a GUI screen capture
- a BER plot with two curves
- coding gain calculations
Typical Comments:
1 no spreadsheet in report: -1
2 no coding gain calculations: -1
3 values in dB should be subtracted: -1
4 no GUI screen capture: -1
5 no BER plot in report: -1
Lab 8 (6)
- test board number
- list of script with changes
- measured transfer function gain & phase (2)
- k = 1.166 (or 1.172 for 29 increments)
- sweep rate = 4/f/14 = 0.28/f
Typical Comments:
1 missing board number: -1
2 missing program listing: -1
3 value of k missing/wrong: -1
4 value of sweep rate missing/wrong: -1
5 arithmetic error: -0.5
6 no plot in report: -1
Lab 9 (5)
- hexedit screen capture with name and all fields correct
- scope screen capture showing single-ended and differential voltages
at start of frame
- Wireshark screen capture
- preamble waveform frequency
- Wireshark does not show preamble or CRC
Comments
1 no/incorrect contents of frame: -1
2 no/incomplete 'scope screen capture: -1
3 no/incomplete Wireshark screen capture: -1
4 no/wrong answer to question: -1
5 screen capture
Midterm Exam 1 (12)
Q1:
- one mark per correct answer
Q2:
- one mark per correct answer
Q3:
- correct bit and baud rates
- correct character value in hex (2)
- correct parity
Q4:
- correctly dividing the UTF-8 sequence
- code point for first character
- code point for second
- ASCII
Midterm Exam 2
Q1:
- -3 if didn't use differential decoding
- -1 per error (up to 2)
Typical Comments:
1 not differential Manchester: -3
2 error: -1
3 no answer: -3
Q2
- -1 per error in calculation (up to 2 errors)
- correct conclusion based on remainder
Typical Comments:
1 wrong conclusion based on remainder: -1
Q3
- flags before & after
- correct bit-stuffing after 5
- correct bit-stuffing after 6
Typical Comments:
1 missing start/end flags: -1
2 missing bit-stuffing: -1
Q4
- correct equation
- correct result
Typical Comments
1 wrong result: -1
2 wrong equation: -1
Q5
- correct dmin
- correct number of correctable errors
- correct corrected c/w
Typical Comments
1 wrong minimum distance: -1
2 wrong number of correctable errors: -1
Final Exam
Q1 (3)
- information rate
- capacity
- conclusion
Typical Comments
1 arithmetic error: -0.5
2 conclusion doesn't match calculations: -0.5
Q2 (2)
- normalized threshold
- answer
*Comments:
1 probability not calculated: -1
Q3 (3)
- correct extraction of bits
- correct grouping into nybbles
- correct answer
* Comments:
1 error in conversion: -0.5
2 incorrect grouping of bits: -1
3 incorrect size of result: -1
4 result not in hexadecimal: -1
Q4 (4)
- correct bit values
- correct bit order
- correct bit polarity
- correct axes scales
* Comments:
1 levels at transmitter should be >+/-5: -0.5
2 wrong polarity: -1
3 wrong bit order: -1
4 wrong parity bit value: -0.5
5 voltages wrong/missing: -0.5
6 wrong units: -0.5
7 wrong conversion to binary: -1
Q5 (2)
- -1 per error
* Comments:
1 wrong bit value: -1
Q6 (2)
- correct value of m
- correct maximum 0-run length
* Comments:
1 wrong equation for m: -1
2 wrong run length: -1
Q7 (5)
- correct CRC length
- correct CRC (2)
- correct message
- correct values of k and n
* Comments:
1 error in CRC calculation: -1
Q8 (4)
- correct minimum distance
- correct detectable errors
- correct correctable errors
- correct most likely codeword
Q9 (2)
- 1 per correct voltage
Q10 (2)
- 1 per correct protocol
* Comments:
1 missing a suitable protocol: -1