THE PENNSYLVANIA STATE UNIVERSITY SCHREYER HONORS COLLEGE SCHOOL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE SOFTWARE DEFINED RADIO RECEIVER

Transcription

1 THE PENNSYLVANIA STATE UNIVERSITY SCHREYER HONORS COLLEGE SCHOOL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE SOFTWARE DEFINED RADIO RECEIVER JAMES PATRICK KELLY SPRING 2017 A thesis submitted in partial fulfillment of the requirements for a baccalaureate degree in Electrical Engineering with honors in Electrical Engineering Reviewed and approved* by the following: James K. Breakall Professor of Electrical Engineering Thesis Supervisor Julio V. Urbina Associate Professor of Electrical Engineering Honors Adviser * Signatures are on file in the Schreyer Honors College.

2 i ABSTRACT With the ever-expanding need of different forms of communication, a demand for a cost effective means of prototyping devices has risen. Modifying already existing pieces of hardware can often be very expensive or not possible at all. A software defined radio (SDR) provides a solution to this problem, providing flexibility and cost efficiency when developing new communications technology. A software defined radio is defined by IEEE as radio in which some or all of the physical layer functions are software defined [1]. Essentially, software defined radio is a radio communications system in which components that are typically implemented as physical pieces of hardware (such as amplifiers, mixers, filters, etc.) are implemented through software on a computer. One of the major advantages of a software defined radio is the flexibility it offers in allowing one piece of hardware to perform multiple functions. For example, when programmed one way, an SDR receiver can function as an AM receiver, but when programmed another way, it can function as a SSB receiver. In this thesis, I will outline programs I created in GNU Radio, an open source SDR development toolkit, which will allow the Ettus USRP N200 software defined radio receiver to function as an AM receiver, a SSB receiver, and a waterfall spectrum analyzer. Furthermore, I will display some of the capabilities of the GNU Radio software when it comes to modulating and demodulating signals through different methods.

3 ii TABLE OF CONTENTS LIST OF FIGURES... iii LIST OF TABLES... iv ACKNOWLEDGEMENTS... v Chapter 1 GNU Radio and SDR... 1 Chapter 2 AM Receiver... 3 Chapter 3 SSB Receiver... 7 Chapter 4 Waterfall Spectrum Analyzer Chapter 5 Differential Phase Shift Keying Chapter 6 Quadrature Amplitude Modulation Chapter 7 Phase Shift Keying Chapter 8 Conclusion and Future Works Appendix A Additional Modulation Simulations BIBLIOGRAPHY... 32

4 iii LIST OF FIGURES Figure 1. Block Diagram of Ettus USRP N200 [4]... 2 Figure 2. Graphical Representation of Amplitude Modulation [6]... 3 Figure 3. GNU Radio AM Receiver Program... 4 Figure 4. FFT Plot of Data from the File Source... 5 Figure 5. FFT Output of AM Program... 6 Figure 6. Signal with Carrier Frequency before and after USB and LSB Separation [8]... 7 Figure 7. SSB GNU Radio Program... 8 Figure 8. Output of the SSB Receiver Program... 9 Figure 9. Waterfall Spectrum Analyzer GNU Radio Program Figure 10. Output of Spectrum Analyzer Program Figure 11. Visual Representation of DQPSK [11] Figure 12. DQPSK Modulation and Demodulation GNU Radio Program Figure 13. Comparison of 4-DPSK Binary [12] and Output of DPSK Mod GNU Block Figure 14. Real and Imaginary Parts of Baseband Signal Figure 15. Output of DPSK Demodulator Figure 16. Visual Representation of QAM [15] Figure 17. QAM Modulation and Demodulation GNU Radio Program Figure 18. Comparison of 16 QAM [16] with Output of GNU QAM Mod Block Figure 19. Real and Imaginary Parts of the QAM Modulate Signal Figure 20. Output of QAM Demodulator GNU Block Figure 21. Visual Representation of PSK [19] Figure 22. PSK Modulation and Demodulation GNU Program Figure 23. Comparison of 4-PSK and DQPSK Constellation Plots Figure 24. Real and Imaginary Parts of the Modulated PSK Signal... 25

5 Figure 25. Output of PSK Demodulator GNU Block iv

6 v ACKNOWLEDGEMENTS Thank you to Dr. Jim Breakall for allowing me to do this work under your guidance, and for inspiring me to pursue a career path in antenna engineering. Thank you to Salih Bostan for helping me with GNU Radio and spending all the time helping me troubleshoot the issues with my programs. Thank you to Tony Reggio for pushing me early on in my academic career, and for teaching me valuable life lessons throughout the semester I had you as a professor. Thank you to Colonel Vincent Tedesco Jr. for the advice and guidance when it came to deciding with what company I want to begin my engineering career. Thank you to Lauren Donohoe for always being available to give me great advice. Finally, I want to thank my parents, Jim and Sally, for always pushing me throughout my academic career. Without your guidance and tough love I undoubtedly would not have been as successful as I have been throughout my college career.

7 1 Chapter 1 GNU Radio and SDR GNU Radio is a free, open source software development toolkit that provides signal processing blocks to implement software radios [2]. GNU Radio operates very similarly to Simulink, in the sense that all programming is achieved through block diagrams and very little to no actual coding. GNU Radio works best on Linux operating systems, and for this project, the open source Linux operating system Ubuntu version was used to run GNU Radio. Finally, GNU Radio operates from python source code. The Ettus USRP N200 Software Defined Radio (SDR) in this case operates from DC to 50 MHz through the use of a 50 MHz daughterboard. It interfaces to the computer through a minimum 1 GB Ethernet cable, and the main driving force behind the unit is a Xilinx Spartan 3A-DSP 1800 FPGA [3]. The programs created in GNU Radio will program the SDR to function as an AM receiver, SSB receiver, and a waterfall spectrum analyzer. The verification of the functionality of these programs is achieved through replacing the SDR source with a file of a recording of signals received by the B200 model SDR. The data was recorded at a 256 khz sampling rate. GNU Radio also has powerful signal processing blocks that can be used to demodulate signals that are transmitted in different formats. Programs were created that function as a phase key shifting (PSK) demodulator, differential phase key shifting (DPSK) demodulator, and a quadrature amplitude modulation (QAM) demodulator.

8 2 Figure 1. Block Diagram of Ettus USRP N200 [4] Figure 1 shows the block diagram of how the Ettus USRP N200 and B200 function. The N200 and B200 have the function of being a transmitter (TX) as well as a receiver (RX). In this project, the only function necessary to complete the desired outcome is the receiver function from RX2.

9 3 Chapter 2 AM Receiver Amplitude Modulation (AM) signal transmission functions by varying the amplitude of a radio carrier wave in proportion to the transmitted waveform as outlined in Figure 2. It is used widely for broadcasting on short, medium, and long wave bands, and the signals tend to be easy to demodulate [5]. Figure 2. Graphical Representation of Amplitude Modulation [6] In this GNU Radio program, the file source is several seconds of data recorded from the Ettus B200 model of signals in the AM band. It was sampled at a rate of 256 khz. Figure 3 shows the block diagram program created in GNU Radio.

10 4 Figure 3. GNU Radio AM Receiver Program The file source block contains the file previously mentioned. The output of this file source block is connected to a GUI (graphical user interface) FFT (fast Fourier transform) sink block to show the power spectrum output of the file. The output of this FFT sink is shown in Figure 4. The signals in the file were sampled at a rate of 256 khz, and given the default sampling rates for GNU Radio blocks are 32 khz or 64 khz, a rational resampling is used to down-sample the signal to 64 khz. This also allowed the signal to be viewed in greater resolution at this point in the block diagram flow.

11 5 Figure 4. FFT Plot of Data from the File Source The data recorded in the file was recorded with the USRP set to 710 khz, and the channel bandwidth of 10 khz. In GNU Radio, when viewing signals from file sources, the program defaults to center the frequency around 0 Hz, hence why the range of Figure 4 is from -120 khz to 120 khz. In order to listen to the desired frequency, a low pass filter with a cutoff frequency of 5 khz is used to filter out all other undesired frequencies. The output of this block is a complex float. In order to listen to the audio signal, the magnitude of this output needs to be taken. This is achieved through the use of a complex to mag block. This signal is then multiplied by a variable that can be adjusted by the user in real time during the execution of the program. This serves as a volume control. The range of human hearing is between 20 Hz and 20 khz. It is industry standard to sample audio at 44.1 k Hz. In order to listen to the audio at this sampling rate, the signal must be down-sampled once again from 64 khz to 48 khz (interpolated by 4, decimated by 3). This is

12 6 achieved through the rational resampler block. The output of this block is connected to an audio sink, and then another FFT sink. The audio sink sampling rate is set to 44.1 khz instead of 48 khz because through testing, 44.1 khz sampling sounded smoother than 48 khz for this given signal. The final output signal is shown in Figure 5. As the plot shows, at 0 Hz (actually 710 khz) is the peak power of the signal now, with the higher frequencies having very low power. Figure 5. FFT Output of AM Program

13 Chapter 3 7 SSB Receiver Single sideband (SSB) modulation is a form of amplitude modulation that uses only one sideband to form the final signal. This provides a much more efficient means of signal transmission in comparison to standard amplitude modulation. It utilizes transmission power and bandwidth much more efficiently [7]. Essentially, SSB modulation involves removing one sideband and the carrier frequency to achieve the final signal. As Figures 6 and 7 show, the carrier frequency has an upper and lower sideband (USB and LSB), but both of these sidebands are the same. Since the bands are the same, only one is needed to recover the signal, and there is essentially no advantage in using one band over the other. Figure 6. Signal with Carrier Frequency before and after USB and LSB Separation [8]

14 8 In this GNU Radio program, a file source was used that is sampled at 256 khz, and has a carrier frequency at 53 khz. The bandwidth of this signal is 1.5 khz. The desired signal had a carrier frequency at 53 khz and a bandwidth of 1.5 khz. In order to receive the signal, the other signals needed to be filtered out, the signal also needed to down-sampled to be able to view the sideband in greater resolution, and it needed to be shifted so it was centered around 0 Hz. This can be achieved through multiple blocks in GNU Radio, however the Frequency Xlating FIR (finite impulse response) Filter can achieve all of these functions in one block. This significantly simplifies the program. By setting the center frequency to khz, the signal is effectively shifted to be centered around 0 Hz. There is also a feature of this block that allows for decimation, and to down-sample to 32 khz, the signal is decimated by a factor of 8. Finally, in the taps section of the filter, the low pass filter is implemented with a cutoff frequency of 2 khz (to avoid loss of information). Figure 7. SSB GNU Radio Program

15 9 The output of the FIR Filter is a complex number, so in order to graph it properly, a type conversion from complex to float needs to take place. This is achieved through the complex to float block. The output of the top terminal is the real part of the signal, and the output of the bottom terminal is the complex part of the signal. These outputs are connected to a throttle block which helps efficiently control sampling when the source is a signal from an SDR. The real and complex parts of the SSB receiver are shown below in Figure 8. The top FFT plot is the real part, the bottom FFT plot is the imaginary part. Figure 8. Output of the SSB Receiver Program

16 Chapter 4 10 Waterfall Spectrum Analyzer A waterfall spectrum incorporates time, frequency, and amplitude into one graph. Based on the intensity of a given frequency, the color of the graph at that frequency will have a corresponding color [9]. Typically, the brighter the color, the higher the amplitude of that frequency. The color drips from the bottom of the graph to the top over time, hence the name waterfall graph, and shows in real time when the amplitude of a given frequency changes. Figure 9. Waterfall Spectrum Analyzer GNU Radio Program This simple waterfall spectrum analyzer program shown in Figure 9 uses the same file source as the AM receiver program, sampled at 256 khz. The file source is connected to a throttle block to efficiently sample the signal at 256 khz. The output of the throttle is connected to a waterfall sink, and an FFT sink. These two sinks were chosen to verify that the waterfall plot

17 was changing properly as the amplitude of various frequencies changed. Figure 10 shows the 11 waterfall plot and FFT plot of the signal source. The FFT plot was included to verify the waterfall plot was functioning correctly. The range of the plot is from -120 to 120 khz because in GNU Radio, when using a file source, by default it shifts the frequency plot to be centered around 0 Hz. Figure 10. Output of Spectrum Analyzer Program

18 12 Chapter 5 Differential Phase Shift Keying Differential phase shift keying (DPSK) is a form of data transmission that indicates the transmitted bits (0 s or 1 s) through changing the phase of the carrier wave signal [10]. The two most common types of DPSK are differential quadrature phase shift keying (DQPSK) and differential binary phase shift keying (DBPSK) [10]. In the program created for this project, the DQPSK mode of the DPSK block was used. In DQPSK, the phase shifts for the carrier wave are 0, 90, 180, and -90, which correspond to the data values 00, 01, 11, and 10 [10]. Figure 11 shows visually how this data transmission is performed. Figure 11. Visual Representation of DQPSK [11] In this figure, the phase shift occurs every 2Tb, where Tb is the fundamental period of the signal. GNU Radio has a signal processing block, titled DPSK Mod that performs either DQPSK modulation, or DBPSK modulation (in this case, DQPSK). Figure 12 shows the GNU Radio program used to modulate and demodulate a random bit stream signal source.

19 13 Figure 12. DQPSK Modulation and Demodulation GNU Radio Program The random source block in GNU Radio can be set to output byte, integer and short. For this program, to emulate an information stream, byte was used. The range of the source is set from 0 to 256 so the source will contain all the information contained within 8 bits (2 8 = 256), and the number of samples is arbitrarily set to 100 to give a long stream of data. The throttle blocks used in this program functions as before. The UChar to Float block is necessary because the random source bit stream output is a collection of unsigned bytes. The UChar to Float block converts these bytes to their floating-point representations. In the DPSK Mod block, the bit stream is modulated. Samples/symbol is set to eight because in each incoming

20 symbol, there are eight complex baseband signals per incoming symbol. This number is the 14 interpolation factor applied by the re-sampler for the pulse-shaping filter in the block. The pulseshaping filter uses raised root cosine, and the excess bandwidth parameter controls the roll-off factor of this filter (commonly known as β) [2] was the default value set by GNU Radio, and through experimentation, this value allows the program to run as desired. The sample is throttled again, and then connected to a constellation sink, scope sink, and the DPSK demodulator. The constellation plot in Appendix A and Figure 13 shows the plot of the four data bits being transmitted (00, 01, 11, 10). Additionally, the program was ran with the random source set to 100k samples and 10 samples, and the results of the constellation plot were similar. Reference Figures A.1 and A.2 in Appendix A to view these results. Figure 13. Comparison of 4-DPSK Binary [12] and Output of DPSK Mod GNU Block The scope sink is connected to the output of the throttle from the DPSK Mod to verify that the signal being transmitted has both real and imaginary parts, and to examine the relationship between the two. Figure 14 shows the output of the scope block, with the blue sinusoidal wave being the real part, and the green sinusoidal wave being the imaginary part.

21 15 Figure 14. Real and Imaginary Parts of Baseband Signal Finally, the signal is demodulated through the DPSK Demod block. This block is set to DQPSK mode to match the mode of the transmitted signal. The excess bandwidth is also set to 0.35 to match the DPSK Mod block. In order to view the bit stream, the output of the DPSK Demod block must be connected to a converter block, UChar to Float to convert the demodulated signal to their floating point representations. In order to verify the demodulator is working properly, the output of the UChar to Float block is connected to a scope sink block. The output of the scope is shown in Figure 15 below. The scope plot of the program ran with the source set to 100k samples and can be viewed in Figure A.3 in Appendix A. This verified the modulation was functioning properly at a higher sample number.

22 16 Figure 15. Output of DPSK Demodulator As shown in Figure 15, the demodulator is working properly. The various durations of one s and zero s represent the different bits being transmitted (00, 01, 11, 10).

23 17 Chapter 6 Quadrature Amplitude Modulation Quadrature Amplitude Modulation (QAM) is a form of modulation in which two carrier signals, out of phase by 90, are modulated. The resultant output has variations in both phase and amplitude. QAM is a common form of modulation used for radio communications [14]. The main advantage of QAM over standard amplitude modulation lies in the fact standard amplitude modulation uses twice the bandwidth in comparison to QAM [14]. 16 QAM occupies 4 bits of information per symbol, shown in Figure 16. There are other forms of QAM, such as 8 QAM, but 16 QAM and 64 QAM are the most widely utilized. Figure 16. Visual Representation of QAM [15] Figure 16 above shows a visual representation of QAM, with the amplitude and phase changing over time. GNU Radio has signal processing blocks that perform QAM modulation and demodulation (titled QAM Mod and QAM Demod ). In this GNU Radio program, an error

24 rate block, which outputs the bit error rate, was used to verify accuracy. Figure 17 shows the 18 complete block diagram of the QAM modulation GNU Radio program. Figure 17. QAM Modulation and Demodulation GNU Radio Program The random source block in GNU Radio can be set to output byte, integer and short. For this program, to emulate an information stream, byte was used. The range of the source is set from 0 to 256 so the source will contain all the information contained within 8 bits (2 8 = 256), and the number of samples is arbitrarily set to 100 to give a long stream of data. The output of this block is connected to the QAM Mod block, which modulates the signal. 16 QAM was

25 19 used in this program, thus the number of constellation points was set to 16. Samples/symbol is set to eight because in each incoming symbol, there are eight complex baseband signals per incoming symbol. After being throttled, the signal is connected to a constellation sink, the QAM demodulator ( QAM Demod ), and a scope sink. The output of the constellation sink, compared with the expected output of a 16 QAM modulator, is shown in Figure 18. The program was run with the random source producing 100k samples, to verify the program could successfully run with different sample levels. The results of this simulation are shown in Figure A.4 in Appendix A. Figure 18. Comparison of 16 QAM [16] with Output of GNU QAM Mod Block The scope sink is connected to the output of the throttle from the QAM Mod to verify that the signal being transmitted has both real and imaginary parts, and to examine the relationship between the two. Figure 19 shows the output of the scope block, with the blue sinusoidal wave being the real part, and the green sinusoidal wave being the imaginary part. The program was run an additional time with the source set to 100k samples to verify the program can run successfully at different sample levels. The scope plot of this simulation can be viewed in Figure A.5 in Appendix A.

26 20 Figure 19. Real and Imaginary Parts of the QAM Modulate Signal The scope plot verifies the QAM modulator is working properly, with there being clear modulation of both amplitude and phase of the transmitted signal. The final part of the program involves demodulating the signal, and this is done through the QAM Demod block. The parameters for this block are set the same as the QAM mod block in order to properly demodulate the signal. Just as the DQPSK mod/demod blocks, the pulse-shaping filter uses raised root cosine, and the excess bandwidth parameter controls the roll of factor of this filter (commonly known as β) [2] was the default value set by GNU Radio, and through experimentation, this value allows the program to run as desired. The output of the QAM demodulator block must be connected to a UChar to Float converter block in order to view the

27 floating point representation of the data being transmitted. Figure 20 shows the output of the 21 QAM demodulator block connected to a scope sink after the data conversion is performed. Figure 20. Output of QAM Demodulator GNU Block Based on the data collected from the scope sink, it is verified the QAM demodulator is functioning properly. The values of 0 s and 1 s are the data points being transmitted by the random signal source.

28 Chapter 7 22 Phase Shift Keying Phase shift keying (PSK) is another form of digital modulation that involves changing the phase 180 of a sinusoidal signal, alternating between -1 and 1 [17]. The phase shifts occur when the data being transmitted changes data states. PSK differs from DPSK in the fact that DPSK has multiple phase shifts, 0, 90, 180, and -90, corresponding to 00, 01, 11 and 10, while PSK only transmits single zeros and ones [17]. The change in phase indicates changing the data stream from a zero to a one, or vice versa. Figure 21 gives a visual representation of simple PSK. Figure 21. Visual Representation of PSK [18] In this GNU Radio program, 4-PSK was used. The end result of 4-PSK is the same as DQPSK, however in this simulation 4-PSK appears to be more accurate. GNU Radio has a signal processing block that performs PSK modulation and demodulation. Based on the constellation plot of the modulated signal shown in Figure 23, the points appear to be more tightly packed in comparison to DQPSK. The GNU Radio block diagram program is shown in Figure 22.

29 23 Figure 22. PSK Modulation and Demodulation GNU Program Just as in the other programs detailed, the random source block in GNU Radio was set to byte. The range of the source is again set from 0 to 256 so the source will contain all the information contained within 8 bits (2 8 = 256), and the number of samples is arbitrarily set to 100 to give a long stream of data. Through testing, 100 appears to be an optimal number of samples to use for programs like these, as it gives enough data points to verify accuracy, and not too many data points that it slows down the program. After the sample is throttled, it is connected to a scope sink block and a constellation sink block. These blocks were used to verify the signal was being modulated properly. Figures 23 and 24 show the outputs of these blocks. In the constellation plot, there are four data points, as expected, and in the scope plot, it is clear the phase is the only thing being modulated in the signal.

30 24 Figure 23. Comparison of 4-PSK and DQPSK Constellation Plots As previously stated, the points of the constellation plot for the 4-PSK modulation appear to be more condensed around the expected points in comparison to the DQPSK points. This could be due to several factors, however the most likely cause of this phenomena is the fact that each point in 4-PSK is modulated individually, and read in 2 bits/byte packets, while in DQPSK, the data is transmitted as 2 bits, and read as such [19]. This could lead to some inaccuracies in the program. The program was ran a second time, with the random source set to 100k samples. This was done to prove the program could function properly at different sample values. The constellation output of this simulation can be viewed in Figure A.6 in Appendix A.

31 25 Figure 24. Real and Imaginary Parts of the Modulated PSK Signal The real and imaginary parts of the PSK modulated are shown in Figure 24 above. This plot verified the modulation technique was functioning properly, as the only property of the signal being modulated was phase. The scope plot of the program when it was ran with the random source set to 100k samples can be viewed in Figure A.7 in Appendix A. This verified the signal was being modulated correctly at 100k samples. Once the signal was throttled, it was filtered through the PSK demodulation block, PSK Demod. This effectively and correctly demodulated the signal. The output of the PSK Demod block had to go through a type change to be able to be read on the scope. The UChar to Float changes the signal to the floating point representation of the data. This data was then connected to the scope sink, shown in Figure 25.

32 26 Figure 25. Output of PSK Demodulator GNU Block The plot above verified the demodulator was working properly, with a random distribution of ones and zeros taken from the random source signal.

33 Chapter 8 27 Conclusion and Future Works There are many different applications for GNU Radio based on the hardware being programmed. It is possible to create programs in GNU Radio that allow an SDR to function as both a transmitter and receiver, and thus the applications of the program are far reaching. Currently software defined radios are being used by everyone from hobbyists, to the military for communications on the battlefield, to hospitals for seamless communication between several wireless devices [20]. The programs created here are only a few examples of the capabilities of GNU Radio. Using a file source, it was demonstrated GNU Radio interfaced with a software defined radio receiver can successfully function as an AM receiver, a SSB receiver, and a waterfall spectrum analyzer. Using a random bit stream and the various modulating and demodulation blocks, it was shown GNU Radio can function as a DQPSK, QAM, and PSK modulating software. In the future the programs created here can be interfaced with a software defined radio and successfully function as an AM receiver, SSB receiver, and a waterfall spectrum analyzer. The DQPSK, QAM, and PSK modulating software can also be interfaced with a software defined radio receiver and correctly receive and interpret data transmitted in those forms.

34 Appendix A 28 Additional Modulation Simulations Figure A.1. DQPSK Program Constellation ran with Source set to 100k Samples Figure A.2. DQPSK Program Constellation ran with Source set to 10 Samples

35 29 Figure A.3. DQPSK Program Scope ran with Source set to 100k Samples Figure A.4. QAM Program Constellation ran with Source set to 100k Samples

36 30 Figure A.5. QAM Program Scope ran with Source set to 100k Samples Figure A.6. PSK Program Constellation ran with Source set to 100k Samples

37 Figure A.7. PSK Program Scope ran with Source set to 100k Samples 31

38 32 BIBLIOGRAPHY [1] "Software Defined Radio", International Journal of Science and Research (IJSR), vol. 5, no. 1, pp , [2] "FAQ - GNU Radio", Wiki.gnuradio.org, [Online]. Available: [Accessed: Dec- 2016]. [3] "USRP Hardware Driver and USRP Manual: USRP2 and N2x0 Series", Files.ettus.com,2017. [Online]. Available: [Accessed: Dec- 2016]. [4] Ettus Research, Ettus USRP N200 Block Diagram [5] I. Poole, "What is Amplitude Modulation", Radio-electronics.com, [Online]. Available: [Accessed: Dec- 2016]. [6] I. Poole, Amplitude Modulation [7] I. Poole, "What is SSB Single Sideband Modulation Tutorial - Radio-Electronics.Com", Radio-electronics.com, [Online]. Available: [Accessed: Dec- 2016]. [8] I. Poole,. An Amplitude Modulated Carrier Showing Sidebands [9] J. Mathey, "Waterfall Analysis: Frequency Spectrum or Order Spectrum?", Prosig Noise & Vibration Blog, [Online]. Available: [Accessed: Dec- 2016]. [10] L. Zhao, H. Shankar and A. Nachum, "40G QPSK and DQPSK Modulation", Inphi, [Online]. Available: Modulation.pdf. [Accessed: 10- Jan- 2017]. [11] M. Gast, Timing Diagram for DQPSK [12] Mathworks, DQPSK Binary Diagram [13] R. Keim, "Learning About Differential Quadrature Phase Shift Keying (DQPSK) Modulation.", All About Circuits, [Online]. Available: [Accessed: Jan- 2016].

39 [14] I. Poole, "What is QAM", Radio-electronics.com, [Online]. Available: [Accessed: 18- Feb- 2017]. 33 [15] Airlinx, Quadrature Amplitude Modulation.. [16] I. Poole, Bit Sequence Mapping for a 16QAM Signal [17] I. Poole, "What is Phase Shift Keying, PSK", Radio-electronics.com, [Online]. Available: [Accessed: Mar- 2016]. [18] I. Poole, Phase Shift Keying (PSK) [19] N. Vlajic, "Analog Transmission of Digital Data: ASK, FSK, PSK, QAM", Stanford University, [Online]. Available: DigitalModulation.pdf. [Accessed: Mar- 2017]. [20] S. Chiao, "Software-defined radio is key to seamless and effective military communication", Military Embedded Systems, [Online]. Available: embedded.com/articles/ software-defined-radio-key-seamless-effective-military-communication/. [Accessed: Apr- 2017].

40 ACADEMIC VITA Academic Vita of James Kelly Education Major(s) and Minor(s): Electrical Engineering, Music Technology Honors: Electrical Engineering Thesis Title: Software Defined Radio Receiver Thesis Supervisor: James K. Breakall Work Experience May 2016 August 2016 AFSP Electrical Engineering Intern Wrote a Matlab GUI program to generate timing diagrams and graph voltage data from data recorded in text file data dumps for the MK21 fuze. These graphs were used for troubleshooting failed test runs for the AFA, PTP and CPC components of the fuze Lockheed Martin Corporation, King of Prussia, PA Rich Gargano May 2015 August 2015 Electrical and Electronics Intern Designed and built a module that emulates the Bosch hydrostatic transmission system. This module was interfaced with a 4Ward technology test fixture and was used for testing with new 4Ward technology. JLG Industries, Hagerstown, MD Dan Smith Professional Memberships: NCEES Fundamentals of Engineering (FE) Certification Six Sigma Yellow Belt Certification