Getting to Know the Laboratory's Equipment - Experiment #1 | ECE 311, Lab Reports of Electrical and Electronics Engineering

Download Getting to Know the Laboratory's Equipment - Experiment #1 | ECE 311 and more Lab Reports Electrical and Electronics Engineering in PDF only on Docsity! ECE-311 Experiment #1 Getting To Know the Laboratory’s Equipment Objective: In this exercise you will become familiar with the communication laboratory’s equipment, which will be used in the hardware experiments during this semester. The three main pieces of equipment are the function generator, the oscilloscope, and the spectrum analyzer. The other piece of equipment that you will use is a power supply. The function generator and spectrum analyzer will be the main focus of your investigations since it is assumed you are all expert oscilloscope users and power supply adjusters. In addition, you will review and use your knowledge and skills in measuring and calculating the power of a signal. Introduction: Your laboratory teaching assistant will give you a brief lecture and demonstration on the use of the function generator and spectrum analyzer. Pre-Lab: Calculate the theoretically expected average and RMS values for the waveforms of Part One in the “Task” section. Calculate the theoretically expected powers for the sinusoids of Part Two in the “Task” section. Express
                
                                        Task: Part One: Use the function generator to produce the following periodic waveforms: Waveform Fundamental Frequency Peak-to-Peak Amplitude d.c. Offset Square wave (Rectangular Wave with 50% duty cycle) 1 MHz 3 volts 0 volts Rectangular Wave with 20% duty cycle 5 MHz 5 volts * Triangular Wave 100 KHz 2 volts * Sawtooth Wave 100 KHz 3 volts 0 volts *Adjust the d.c. offset so the “baseline “ of the signal is zero volts. a) Display each waveform on the oscilloscope. First, show one period and then ten periods. b) Use the oscilloscope’s “soft” keys to measure the signal’s frequency, average value, and RMS value. Record these values. c) Draw a sketch of each waveform. Label all critical points. (One period will be adequate.) Part Two 1. Produce a 1 MHz sine wave with an amplitude of one (1) volt (2 volts peak-to-peak) and an average value of zero. Use the oscilloscope to verify the signal’s parameters. 2. Next, use the spectrum analyzer to measure the signal’s amplitude in dBmV and volts and its power in dBm. Record these measurements 3. Repeat the previous two steps for sinusoids of amplitudes of two (2) and three (3) volts. 4. Repeat the previous three steps for a sinusoid of 5 MHz. Note that you will have taken data for six different sinusoids. If you are having difficulty doing any of these measurements, ask for help from your laboratory teaching assistant. Data Analysis: For Part Two’s data, is there any relationship between the theoretically calculated and measured amplitudes and powers? There may not be any obvious correlation between the two because of either an unforeseen systematic error in taking the data or a mistake in the circuit model used to do the theoretical calculation. However, if you choose one signal as a reference signal (say the unit amplitude sinusoid) and take the ratio of the other signals’ amplitudes (or powers) to it. The expected and measured values of these ratios should be very close. This illustrates a very important fact in communication systems; it is the relative signal levels that are important not absolute levels. Report: In your report for Part One include the sketches of the periodic waveforms you studied and a comparison of the calculated and measured average and RMS values. In your report for Part Two include a table (see below) comparing the expected and measured values for the amplitudes and powers of the various sinusoids along with the ratios you calculated in the “data analysis” section. Freq. (Hz) Expected Amplitude (dBmV) Measured Amplitude (dBmV) Calculated Power (dBm) Calculated Relative* Power (dB) Measured Power (dBm) Measured Relative* Power (dB)




















*Use the unit amplitude sinusoid as the reference. Prelative (dB) = P (dBm) – Preference (dBm)