The numbers in parentheses indicate the number of marked items (1 mark each). Labs Lab 1 Pre-Lab (3) - name, date and title - table showing bit values and voltages - C program Lab 1 Report (4) - audacity screen capture - 'scope screen capture - hexedit screen capture - corrected C listing Lab 2 Pre-Lab (4) - correct voltages (>3V or <-3V) - correct file size = 160 + 160x# characters - C program writes correct values (0x0000 and 0x3fff) - C program writes bytes in correct order (LS byte first) Lab 2 Report (3) - terminal screen capture - 'scope screen - program listing Lab 3 Pre-Lab (3) - C, L per meter for Cat 5 cable - C and L values for 1 and 5 meters of cable - a spreadsheet with 6 columns Lab 3 Report (4) - table includes equation for L=1/(4 pi^2 f^2 C) - includes calculated result for capacitance/m ~50pF/m - a comparison of C and H per meter to published values Lab 4 Pre-Lab (3) - V/6 volts/division - (3/f)/14 or 3/(14xf) or 0.21/f us/division - RMS measurement Lab 4 Report (3) - reasonably well-formatted graph of amplitude and phase response - roll-off of about 12~dB/octave - unique spreadsheet included (not a copy of someone else's) Lab 5 Pre-Lab (2) - 2(c) probability density has two values with voltage = -2 and 1 - 4(b) 10/256 = 39mV Lab 5 Report (4) - plot of Gaussian noise waveform - 3 screen captures - histograms for sine and noise - RMS voltage from sine wave histogram ~= measured value Lab 6 Pre-Lab (3) - q2: > returns vector/matrix of 1's or 0's if LHS greater the RHS (right hand side) - q3: 2 rows, 3 columns - q8: at 1 MS/s and 10 samples/bit the bit rate is 100 kb/s Lab 6 Report (3) - 3 screen captures - 3 correct spectra - frequency of nulls is 100 kHz for NRZ, 200 kHz for Manchester Lab 7 Pre-Lab (3) - 2(a): 2 tx, 2rx - 2(b) for transmitter: TTL levels (0-5V) on inputs, approx +/-10V on outputs - 6: max 30V/us Lab 7 Report (3) - 1. reasonable mark/space voltages (~9V) - 2. reasonable output impedance measurement (>300 ohm) - 4. slew rate measurement (reasonable data and result <30V/us) Lab 8 Pre-Lab (2) - spreadsheet - graph Lab 8 Report (3) - 'scope noise screen capture - table with reasonable range of BER (~1e-2 to ~1e-6) - graph with reasonable agreement between theory and measurement Lab 9 Pre-Lab (1) - screen capture of hexedit with a reasonable approximation to an Ethernet packet Lab 9 Report (5) - hexedit screenshot with a correct packet (including name, padding and CRC) - 'scope screen capture showing both TD+/TD- and the differential voltage during the preamble - wireshark capture showing name - answer to question (2): frequency = 5 MHz - answer to question (4): preamble and CRC not shown Assignments Assignment 1 (12) Q1: (c) equation including truncation or rounding (d) correct values (quantized or not) Q2: (b) number of bytes (typically 3 per character) (d) code points (plausible values) Q3: - description of method used - entropy ~= 4 bits/character Q4: (a) about ~= 11,600 seconds (b) throughput ~= 6900 bps Q6: (a) a valid IC part number Q7: - a length of open-circuited transmission line - l ~= 0.3m Q8: - Ae ~= 1 sqm Assignment 2 (5) Q1: curve should have maxima/minima equally above/below 1 with maxima between 1.1 (a=0, x=0.1) and 1.8 (a=9, x=0.82) at f=0 and should have minima every 500 Hz (b=0, tau=2ms) to 153 Hz (b=9, tau=6.5ms) (a and b are middle two digits) Q2: 500ns Q3: 1.98 MHz Q4: 65% Q6: 84% (Question 5 was not marked because question does not actually ask you to run the program!) Assignment 3 (11) Q1: prints approximately 1% or 0.01 or 14,000 Q2: 67% Q3: -6dB at 129 kHz Q4: graph looks (by eye) correct for alpha Q5: 256us = 512 samples (or 276 = 552) Q6: p<3% and p>97% Q7: (a) 4.4 Mb/s (c) BER = 4E-6 Q8: spectrum shows peak at about 40 kHz Q9: correct flags and escaping Q10: differential voltage is +/-5 V common mistakes: [copying a] program that calculates the number of frames with <3 errors. capacity calculated using S/N as a voltage ratio. questions not answered. arithmetic/algebra errors. wrong frequency axis values. BER given in units of errors per second (not marked as an error). Assignment 4 (8) Q1: E4 Q2: (b) dmin=3 (c) codeword C (CDA) transmitted Q3: (a) A=(1)1[0], B=(1)0[1] {(given)answer[next]} Q4: CRC=0001 Q5: any reasonable OUI lookup Q6: (b) Ethertype=ARP (c) payload is 28 bytes Mid-Term Exam One mark was assigned for each of the following essential elements of a correct solution: Question 1 (3) - computing log(probability) for each message - computing the weighted sum - right answer Question 2 (4) - correct bit and baud rate - correct bit order and polarity - correct hex value - correct character Question 3 (3) - convert from AWG to mm - use correct equation for Z0 - right answer Question 4 (3) - type of channel (LPF) - bandwidth - signal level Final Exam Question 1 (5) - log2(4)/1E-6 = 2Mb/s - 1/1E-6 = 1MHz - correct formula for calculating entropy - correct answer (1.85 [Mb/s]) - 1/0.5E-6 = 2 MHz Question 2 (4) - correct bit values and order (2) (0x97 and 0xE3) - correct bit rate (9600 and 19200) - polarity, type (odd) Question 3 (4) - used Friis formula - solved for distance - correct wavelength and conversion from dB - correct answer (265m or 839m) Question 4 (3) - correct CRC length - correct calculation of remainder - correct conclusion about errors from result Question 5 (8) - answers: 2, 6, 1/3 (by inspection) (0.5 if partially right) - calculations of distances - answer = 3 - dmin-1=2 - (dmin-1)/2=1 - yes, not a valid c/w - 101100 or 000110 - yes, anything is possible Question 6 (10) - use Stop and Wait; explanation (2) - output on RxD->DCE, on TxD->DTE; null modem (2) - 100m; 100/2e8= 0.5us (2) - half of bit rate (500kHz or 1MHz); minimum is a brick-wall response (2) - transformer - THD