The numbers in parentheses indicate the number of marked items (1 mark each).

			      Labs

Lab 1 Pre-Lab (3)

- average and RMS for random waveform (average = 1.4, RMS = 2.4V)
- DMM frequency range up to 100kHz
- 1024 levels for 10-bit ADC

Lab 1 Report (3)

- time-domain plot of square wave from at least +3 to -3
- histograms of Gaussian noise with RMS (2/3 of peak voltage) at ~= +/- 1.3V
- table with ~0.125 mVrms for DMM measurement of noise rms voltage

Lab 2 Pre-Lab (4)

- correct sum of digits
- AWG sample rate = 24kHz
- waveform diagram w/ correct start/stop bit order and polarity
- C program

Lab 2 Report (5)

- id
- hexedit screen capture
- audacity screen capture
- 'scope screen capture
- C listing

Lab 3 Pre-Lab (4)

- high >+3, low <-3 (or 5)
- connect to RxD (pin 3 on 25-pin connector, pin 2 on 9-pin)
- rate = sample rate/8 = 4800(0,1,4,7), 9600(2,5,8), 19200(3,6,9) bps
- C code

Lab 3 Report (3)

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

Lab 4 Pre-Lab (3)

- equation for L = 1/((2pif)^2C)
- capacitance between ~50 and ~250 pF
- a spreadsheet

Lab 4 Report (2)

- spreadsheet with (reasonable) results for line capacitance,
  inductance and length
- comparison of C and H per meter to published values

Lab 5 pre-Lab (3)

- reasonable code
- V/6
- multiply by 2*sqrt(2) ~= 2.8


Lab 5 Report (3)

- C code
- graph showing amplitude and phase
- rolloff (about 12dB/octave)

Lab 6 Pre-Lab (3)

- 1: schematic
- 2b: on transmitter outputs should have typical +/-9V (minimum +/- 5V)
- 6: 30V/us max slew rate (or 3V typical)

Lab 6 (4)

- reasonable mark and space voltages (typically at least +/-7V)
- reasonable output impedance (typically ~300 ohm at 2V out)
- reasonable input impedance (typically 3k at ~3V in)
- reasonable slew rate measurement (typically 30V/us)

Lab 7 Pre-Lab (2)

- spreadsheet
- BER graph

Lab 7 Lab (4)

- noise plot
- screen capture of data and noise
- table of BER vs SNR
- plot of BER vs SNR

Lab 8 Pre-Lab (3)

- q1: randn(1,n) returns row of n random numbers between 0 and 1
- q4: subscripting with (:) returns a column vector
- q5: .' is transpose

Lab 8 Report (5)

- 3 waveforms
- 3 spectra
- data rate = 100kb/s in all cases
- Manchester: baud rate=200kHz
- Manchester has widest spectrum, least power at DC

Lab 9 Pre-Lab (1)

- schematic

Lab 9 Report (2)

- final schematic
- correct waveform

Lab 10 Pre-Lab (1)

- screen capture

Lab 10 Report (5)

- hexedit contents
- 'scope screen capture 
- wireshark screen capture
- question2: preamble frequency is 5 Mb/s because of alternating 0/1
- question5: wireshark doesn't show preamble or CRC (FCS)

Lab 11 Pre-Lab (3)

- filter restricts displayed packets
- click on + or > to show more/less details
- packet contents window shows details

Lab 11 Reports (5)

- IP address of gaia.cs.umass.edu = 128.119.245.12
- packets headers included in report
- q3: upper-layer protocol in IP header is ICMP
- q4: header has 20 bytes, payload has total length - 20
- q6: destination and source addresses remain constant


			   Assignments

Assignment 1 (12)

Q1 (2)

- code point is U+5154
- encoding is E5 85 94

Q3 (2)

- 8 symbols
- log2(N) bits/symbol

Q4 (2)

- 1280 bits
- throughput is 64 kb/s

Q8 (2)

- e_r ~= 1.8
- Zo ~= 68

Q13 (2)

- phase starts/ends at 0
- 4 cycles

Q16 (2)

- about 7%
- about 16%

Assignment 2 (10)

Q1 (a): N=16 levels
Q2 (a): 8mA
Q2 (c): 16pF
Q3 (a): load=24W, cable=2W
Q4 (a): 31ms
Q5 (a): MLT-3
Q5 (b): Manchester
Q5 (d): AMI
Q6: 19.5 kHz
Q7: 43 Mb/s

Assignment 3 (7)

Q1: starts with flag, 5x1, 0
Q2a: CRC = 011
Q2b: CRC = 100
Q3: 4 padding bits
Q4a: 1 minimum
Q5: 50 bits
Q6: 127 bits 

Assignment 4 (8)

q1: (a) HDLC: L2
    (c) LPF: L1
    (d) world-wide address: L3
q3: STP
q5b: 0x0800 (IPv4)
q5c: 52 bytes
q5d: 6 (TCP - this is actually the protocol field) 
       (also accepted 4 for IPv4 although this is the 
	protocol version)
q6: 1,1, 0,1, 1,1 (for input 111) OR
    1,1, 1,0, 1,0 (for input 110)

			  Mid-Term Exam

Q1 (3)

- using correct line of Table 3-6
- correct bits extracted
- correct answer

Q2 (3)

- one for each correct answer (0.5 if got bits/symbol right)

Q3 (3)

- 1 for Manchester
- 1 for differential
- 1 for correct waveform

Q4 (4)

- correct equation fo e_r
- correct e_r
- correct equation for t
- correct t (using above e_r)

Q5 (3)

- correct t
- 1-P(t)
- correct answer

			   Final Exam