Resonance Finder...N Netflix O Twitch School of Electronic and Communications Engineering If...
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Resonance Finder 6.101 Final Project Alec Reduker
Transcript of Resonance Finder...N Netflix O Twitch School of Electronic and Communications Engineering If...
ResonanceFinder
6.101 Final Project
Alec Reduker
Motivation and InspirationProx cards!
Simplified to prox card reader
Generalized to all resonant circuits
Grid Dip Meters… Are Bulky and Old!Dip in power dissipated at resonance
Requires manual tuning
P
f0
Photo by Arnold Reinhold
A More Clever ApproachUse the phase difference of the input and response
Phase of the input voltage and current are in phase at resonance
...Using a Phase Detector and Controller,
we can adjust a VCO to drive a circuit at
resonance
VCO DesignA Clapp Oscillator is a common
topology for VCOs. A varactor diode
will supply the variable capacitance.
Analog Phase Detector DesignA Gilbert Cell is a frequency mixer. When
Both inputs are sinusoids…
DC component is proportional to phase shift
Controller DesignProportional controller at first
-Simple differential amplifier
Inaccuracies from VCO and Phase
Detector could invalidate the benefits
from a better controller.
Everything is Hard in AnalogThe amplitude of the current will vary drastically -- this could make detecting the phase difference very hard.
Since there is a feedback loop, all of the components have to “play nice” with each other.
Timeline
Item Deadline
VCO, Phase Detector, and controller 4/27
Interface VCO and P.D. with controller, and debug
5/4
Implement wireless coupling and improve bandwidth
5/11
