Baseband PPM and PAM Algorithm Implementation Kenneth Rice Joel Simoneau Dr. Pearson Summer Undergraduate Research Experience

Purpose Main Objective: Create a library of available baseband communications algorithms Secondary Objective: Test the algorithms for efficiency and productivity based upon certain noise situations

Outline Pulse Amplitude Modulation Pulse Position Modulation Demodulation Techniques: Matched Filter Time Limited Accumulation Filter Direct/Reflect Path Noise Random Inversion Noise Algorithm Implementation Testing Future Work

Pulse Amplitude Modulation The amplitude of the pulses denote the information that is sent Example:

Pulse Position Modulation The location of the pulse within the specified pulse frame indicates what was sent Example

Matched Filter

Time Limited Accumulation

Direct/Reflected Path Noise When the transmitted signal changes path during transmission in such a way that the signal is inverted when received

Random Inversion Noise Transmitted signal randomly inverts at any given moment during transmission

Algorithm Implementation Pulse Amplitude Modulation (PAM) Pulse Amplitude Demodulation (PAD) -Matched Filter Pulse Position Modulation (PPM) Pulse Position Demodulation (PPD) -Matched Filter -Matched Filter Altered -Time Limited Accumulation (TLA) Filter -TLA Altered

FPGAs

Circuit: PAM PAM: Transmitter ‘1’ -> ‘001000’ ‘0’ -> ‘111000’

Circuit: PAD PAM: Receiver

Circuit: PPM PPM: Transmitter ‘1’ -> 0400-Hex ‘0’ -> 8000-Hex

Circuit: PPD-Matched PPD: Matched Receiver

Circuit: PPD-Matched Altered PPD: Matched Altered Receiver

Circuit: PPD-TLA PPD: TLA Receiver

Circuit: PPD-TLA Altered PPD: TLA Altered Receiver

Testing Table 1: Direct Path / Reflected Path Results Design101 bits1001 bits Matched44 errorsN/A Matched (Altered)0 errors TLA0 errors5 errors TLA (Altered)0 errors SNR is 4.8 for the also included Gaussian noise

Testing (continued) Design101 bits1001 bits Matched42 errorsN/A Matched (Altered)24 errors266 errors TLA0 errorsN/A TLA (Altered)24 errors266 errors Table 2: Random Inversion Results SNR is 4.8 for the also included Gaussian noise

Future Work Testing with a more accurate channel model Quantify the relative complexity of the various algorithms to give a performance versus FPGA memory trade-off

References [1] L.C. Ludeman, Fudamentals of Digital Signal Processing. New York: Harper and Row, [2] M.B. Pursley, Introduction to Digital Communications. New Jersey: Pearson Prentice Hall, 2005.