First Advisor

Richard L. Campbell

Term of Graduation

Winter 2024

Date of Publication

2-8-2024

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Electrical and Computer Engineering

Department

Electrical and Computer Engineering

Language

English

Subjects

Frequency Mixer, Mobile Communication, Polybius Square, Quadrature Modulation, Radio Frequency Engineering, Test Engineering

DOI

10.15760/etd.3722

Physical Description

1 online resource (xii, 81 pages)

Abstract

This thesis outlines the design of an IQ Test Bench that allows for experimentation of quadrature modulation techniques. Quadrature modulation utilizes two signals I and Q, 90° out of phase from each other, to greatly increase communication data rates. Using Desmos, a thorough mathematical analysis of waveform mixing is presented, and constellation diagrams are plotted from the results. From this an ancient fire signaling technique known as the Polybius Square is encoded into the system. The IQ Test Bench is built from fundamental components that would be contained within an RFFE: a local oscillator and two frequency mixers. The LO is a custom built 7 MHz Colpitts oscillator with buffer and driver stages that provides +10 dBm output power. A hybrid coupler both splits the power down to the ideal +7 dBm and provides the 90° phase shift to the Q signal. The I and Q mixers are ADE-1s, a popular packaged diode ring mixer. Two signal generators provide I and Q data to the mixer inputs to send "Hello World" via the Polybius Square encoding. At the RF output a Wilkinson splitter is used to combine the I and Q mixed signals. A spectrum analyzer, oscilloscope and power meter are used to troubleshoot the system and confirm mathematical, simulation, and measured results.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Persistent Identifier

https://archives.pdx.edu/ds/psu/41654

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