Lab Marking Scheme The following sections describe how the Pre-Lab Assignments and Lab Reports were marked. Each item shows the marks awarded and what was required to get that mark. Marks for each marked item are given in parentheses. Lab 1 - Generating Test Signals Lab 1 PreLab - the pre-lab was checked during the lab, everyone received full marks (10) Lab 1 Report - name, id, course, date and lab number (5) - correct number in decimal (5) - 12-column/row x (3-row/column) table with bit number, correct start, data and end bit values and levels (5 marks per row/column, total of 15) - screen capture (5) - program listing (5) - penalty for submitting in wrong format: -10 Total: 35 Lab 2 - Measuring Transmission Lines Lab 2 PreLab - these were checked during the lab Lab 2 Report - identification: 1 - calculations spreadsheet: 1 - correctly computed values of capacitance (~50pF/m), inductance (~0.5uH/m) and length (varies): 3 - computation of characteristic impedance (approx 100 ohms): 1 - computation of capacitance per unit length (approx 52pF/m): 1 - comparison with published values: 1 wrong file format: -4 Total: 8 common mistakes: giving inductance results in milliHenries (1mH is 1E-3 Henries, not 1E-6) Lab 3 - RS-232 Serial Interface Waveform Lab 3 Pre-Lab - C program (5, one mark each of two loops, one mark for generating each of start and stop bits, 1 mark for including a way to test individual bits) - baud rate computation (2, one for dividing sample rate by samples/character, one for a correct answer=9600) - op-amp questions (4, one mark per correct answer: 0, 4.9:1, ~5, +/-15V or +/-10V) Total: 11 Lab 3 Report - indentification information (5 marks, as in previous labs) - screen capture (5 marks for screen capture showing the student's name) - copy of code (5 marks for a complete, working C program) Total: 15 Lab 4 - RS-232 and RS-422 Interface Circuits Lab 4 Pre-Lab A mark of 0 (zero) was given if any of the material in the pre-lab was copied without referencing the source. Part 1 : RS-232 - schematic of MAX-232 interface circuit, (1) - two charge pumps generate higher and negative voltages (1) - handshaking: H asserts, data: L is one/1 (1) Part 2 : RS-422 - schematic (1) - specification requires an output difference <6V (1) - only the differential voltage is used for signalling (in particular, we can use the two TTL logic levels relative to ground of +5 and 0 or 0 and +5) (1) Total: 6 Lab 4 Report Marks were assigned for reasonable measured values of: - identification (1) RS-232: - mark and space voltages ~8V (1) - output impedance ~300 ohms (1) - input impedance ~7k ohms (1) - slew rate ~10 V/us (1) RS-422: - sketch of the two RS-422 voltages showing outputs are complements of each other (1) - sketch of differential voltage showing +ve and -ve values (1) - comparison of bit rate to RS-232 (faster) (1) Total: 8 Lab 5 - Signal Analysis Lab 5 Report - zip file with three .csv, one xls and one PDF file (1) - report with: - plots of the three waveforms (1) - each raw sample value requires 2 bytes (1) - three histograms (1) - reasonable agreement between measured and computed RMS values (1) - if not submitted as a ZIP file or report not in PDF format: -2 Total: 5 Lab 6 - Self-Synchronizing Descrambler Lab 6 Pre-Lab - a schematic including 9 shift registers and a 3-input xor (1) Total: 1 Lab 6 Report - identification (1) - schematic (1) - test waveform (1) Total: 3 Lab 7 - FSK Modulator Lab 7 Pre-Lab - power is A^2/2 or A^2/(2R) if R is not 1 (1) - -6dBm is 0.25mW = A^2/2 / 600 A = sqrt(2*0.25E-3*600) = 0.55V (1) - mark = 980 Hz phase increment = 980 * 360 / 9600 = 36.75 degrees (0.6414 radians) per sample (1) - space = 1180 Hz phase increment = 1180 * 360 / 9600 = 44.25 degrees (0.7723 radians) per sample (1) - 9600 samples/second / 300 bits/second = 32 samples/bit (1) - code including the following: - loop for 32 samples per bit (1) - a phase increment that depends on the bit value (1) - if not in PDF format: -3 Total: 7 Lab 7 Lab - code: 1 - screen capture: 1 Total: 2 Lab 8 - BER Measurement (ELEX 3525 Only) Lab 8 Pre-Lab - identification (1) - modified schematic (1) Total: 2 Lab 8 Report - identification (1) - schematic with LFSR correct taps (27,30) and (6,9) (1) - spreadsheet with required columns (1) - spreadsheet showing decreasing BER with increasing SNR (1) - a graph with log and dB axis (1) - graph showing the trend in the spreadsheet (1) - if not in PDF format: -2 Total: 5 Lab 9 - IP and Wireshark Protocol Analyzer Lab 9 Pre-Lab Marks were awarded as follows: - top-level protocol (1) - display only packets matching filter expression (1) - click on '+' or '-' (1) - bottom window (1) Total: 3 marks Lab 9 Pre-Lab Answers to the following questions: - your name, ID, lab number (1) - the highest-level protocol indentified by Wireshark in the current frame (1) - show only those frames matching the filter expression (1) - click on the + (for more details) or - (for less) icons in the frame detail window (1) - the bottom window shows the contents in hex (1) Total: 5 Lab 9 Report - name and ID: (1) Part 1: - any 3 protocols (1) - a delay of about 80ms (1) - 128.119.245.12 and any address in 142.232.0.0/16 (1) - screen capture showing reasonable GET and OK IP addresses and times (1) Part 2: - upper layer protocol is ICMP which has value 1 (1) - bytes in IP header = 20 = 5 (IHL field value) x 4 bytes/word (1) - a field that stays constant in requests: destination IP address (1) - value of Identification field in requests changes with each frame (1) - value of Identification field in responses changes with each frame (1) Total: 10 Lab 10 - Digital 'Scope Familiarization (ELEX 3525 Only) Lab 10 Report Report: - student name, ID and date (1) - model and serial number (1) Answers to questions: - sampling rate for two channels: 1 Gs/s (1) - the 'scope has settings to scale the readings by 10x when using a 10x probe (1) - a 70MHz 3dB bandwidth means the amplitude would be -3dB = ~0.7V or 1.4Vpp (1) - printer icon button: prints the screen to attached printer or USB drive (1) Total: 6