Marking Scheme

			   Final Exam

Marked out of 30:

Question 1 (5)

(a) 2 (method, answer)
(b) 1 (method)
(c) 2 (method, answer)

Question 2 (5)

(a) 1 for correct n, k
(b) 1 for correct codeword, 1 for distance calculations (or similar)
(c) 1 for hamming distance
(d) 1 for correct bit in error

Question 3 (4)

1 for each correct ascii character (total of 2)
1 for correct UTF-8 encoding method
1 for correct final answer 

(awarded 2/4 if used too many bits in the encoding of the first
two bytes, 1/4 if tried to UTF-8 encode all characters)

Question 4 (5)

1 for bits & order
2 for MLT-3 encoding (2 marks, -1 per error) 
1 for voltage scale (+/-1V)
1 for time scale (10ns or 8ns per bit)

Question 5 (5)

1 for checksum
2 for calculation (method, result)
1 for protocol 17
1 for 255.255.255.255 (broadcast, all)

Question 6 (3)

1 for t
1 for probability = 98%
1 for answer (2%)

Question 7(3)

3 (1 per right answer)


			  Mid-Term Exam

Question 1

- binary value of the letter
- correct data bit values (order, voltage)
- correct start/stop and parity bit values (order, voltage)
- matching drawing with correct voltages, bit duration

Question 2

- value of t
- probability
- expected number of errors

Question 3

- cable attenuation (3dB)
- power level
- voltage

			   Assignments

One mark was assigned for each of the following:

			  Assignment 1

marked out of 5:

q1: first 3 values: 25 50 44
q2: entropy = 2.45
q3: Ethiopic See
q4: code point 0x54f2
q5: FER = 3.1E-5

			  Assignment 2

marked out of 8:

q1: ~14AWG
q3: 26 GHz
q4: LMR-400
q5: 103 dB loss (or 17dB gain!)
q7: +/-26 kHz (52kHz)
q9: non-linear
q11: THD = 0.01 or -20dB (inverse OK)
q16: 1kHz

			  Assignment 3

marked out of 10:

q1: 30 ohms
q1: 4 or 5V
q3: 160 ohms
q5: 1100 (1111) 010
q6: A 1 1 2 A A 4 A 2
q7: 2 padding bits
q8: n=6, k=2, n-k=4
q8: dmin=3, detect 2, correct 1
q10: 1100 10
q11: CRC=00 (-1/2 if 0)

			  Assignment 4

marked out of 6:

q1: 2.5MHz
q2: 18degrees, 3.2
q4: 15 bits
q4: 0, 1, 1, 1 
q6: selective repeat
q7: checksum = 92E4


			      Labs


Lab 1 Report (5)

- cover page with complete information
- sine wave screen capture of the correct waveform
- three measurements (1kHz, 1Vpp, 0.353Vrms)
- falling edge screen capture of the correct waveform
- fall time measurement (20ns)

Lab 2 Pre-Lab (3)

- sum of digits
- sample period
- a reasonable attempt at a C program 

Lab 2 Report (5)

- cover page information
- table showing bit values and polarities
- audacity screen capture
- 'scope screen capture
- the program that generated the above waveform

Lab 3 Pre-Lab

marked out of 5:

1 a spreadsheet
1 5 or more columns
1 a row for measured resistor value
1 a row for null frequency
1 a row for length

Lab 3 Report

marked out of 4:

1 ID information
1 filled-out spreadsheet
1 characteristic impedance and capacitance/meter
1 comparison to published values

Lab 4 Pre-Lab

marked out of 3:

1 sine and square RMS (Vpp/2/sqrt(2), Vpp/2)
1 RMS = sqrt(1^2*0.3 + 3^2*0.7) = sqrt(0.3+0.63)=0.96
1 256 levels

Lab 4 Report

marked out of 4:

1 for csv & excel files
1 for 3 plots
1 for 2 histograms
1 for 3x3 table

Lab 5 Pre-Lab

marked out of 4:

- C code
- RxD (or pin 3, although it varies): this is an input on a DTE
  and an output on a DCE
- bit rate = sample rate/8
- correct sample rate for student ID


Lab 5 Report

marked out of 4:

- ID
- Teraterm screen capture
- 'scope screen capture
- C code

Lab 6 Pre-Lab

marked out of 1:

- C code

Lab 6 Report

marked out of 5:

- C code
- a graph
- properly formatted (log-log scales, labelled axis, title, legend)
- answer: low-pass
- answer: ~30kHz to ~50kHz


Lab 7 Pre-Lab

marked out of 5:

- MAX 232 schematic
- charge pump increases/inverts voltage
- 30V/us slew rate spec
- MC3487/3486 schematic
- rise time = 20ns

Lab 7 Report

marked out of 5:

- max232 H/L voltages
- max232 output impedance
- receiver input impedance
- mc3487 differential scope screen capture (+/-5V)
- RS-422 slew rate


Lab 8 Pre-Lab

marked out of 4:

- sine wave voltage ~0.25Vrms
- samples/bit ~=32
- Teraterm response to more/fewer bits (generic answer OK)
- code


Lab 8 Report

marked out of 4:

- ID
- code
- teraterm screen capture
- 'scope capture


Lab 9 Pre-Lab

marked out of 4:

answers to the 4 questions:
- protocol column ("highest layer protocol")
- filter in packets
- click +
- packet detail window

Lab 9 Report

marked out of 7:

Intro:
q1: 3 different protocols
q3: IP addresses of umass server
q4: screen capture of displayed protocol

IP:
q1: IP address of bcit client (or home PC, but not UMass server!)
q2: highest protocol layer is ICMP
q5: IP ID field always changes
q6: IP source address doesn't