THEREMINTheremin TeamResponsibilitiesMotivationProblemsDesign RequirementsContinuous/Discrete Frequency ControlFront Panel: Frequency ControlsTuningTheremin Modular DesignTest SpecificationsFuture Work•Mississippi State University •Department of Electrical and Computer EngineeringThereminTHEREMINDouglas [email protected] [email protected] Jun-Fey [email protected] Beng [email protected]. Raymond Winton Faculty Advisor ThereminTheremin TeamThereminResponsibilitiesDouglas Beard:Analog to DigitalDigital to AnalogMicroprocessorMicah Caudle:Oscillators.Beat frequency extractor.Voltage to FrequencyWay Beng Koay:Frequency to Voltage ConversionVoltage to FrequencyJeffrey Jun-Fey Wong:Output StageFootswitch CircuitTuner OutThereminQuality theremins are too expensive.•$350-3,500Theremins are hard to play because they are continuous frequency instruments like violin or trombone. MotivationLimited playing style currently prevents broad use. A more versatile theremin will expand use.Theremin• Lack of Reference: Since the thereminist does not actually touch the theremin, the thereminist has no point of reference for notes and nothing to steady his or her hand.Problems• Discrete Frequency: The.• Tuning: The human ear is sensitive to notes that are played off key. Thus, the discrete notes must be very close to the correct note to avoid dissonance.Theremin•Discrete Frequency Accuracy –Switchable between playing the traditional continuous range and playing only distinct frequencies in selectable scales with error < 0.1%.•Tuning–A small amplitude signal will always be present at the 1/4" tuner out jack to enable the performer to locate starting pitches and for pitch verification during practice.•Precise Articulation–A footswitch will connect to the theremin to enable the performer to quickly and easily articulate notes.•Frequency Range–A frequency range of four octaves with a center frequency at 440Hz.Design RequirementsThereminContinuous/DiscreteFrequency ControlDiscreteFrequency ControllerFixedOscillatorVariableOscillatorSummingVolume Control &Audio OutputAntennaSwitchContinuousDiscrete Keyb#ABC DEFGChromaticContinuous ModeTraditional OperationKey Circuitry BypassedDiscrete ModeChromaticBypass Right Selector SwitchThereminFront Panel: Frequency ControlsDiscrete ModeB Flat ScaleBb C D Eb F G AThereminTuningThereminSabine STX-1100 A . B C . D . E F . G .FLAT IN TUNE SHARPTheremin Modular DesignVariableOscillatorFixedOscillatorDetectorPitch ControlFreq-VoltageConverterVoltageComparatorVoltage-Freq ConverterDiscrete Frequency ControllerVariableOscillatorVolumeTuningVolume ControlVCAProcessorVoltage ControlledAmplifierOutput ControlFreqSwitchThereminTuner Out SignalFootswitchAmplifierSignalThereminREQUIREMENTS ANTENNA SIMULATIONCIRCUIT DESIGN & SIMULATIONLABORATORY EVALUATIONPitch Oscillator Ckt - -Volume Control Ckt - -Antenna Capacitance - Fixed Pitch Accuracy -Frequency Range - -Tuner Out Ckt - -Foot Switch Ckt - -Power Supply - Cost - Test SpecificationsTheremin• (range center).Future Work• Using a 12 bit D/A would be more cost efficient. This D/A would still maintain less than .2% pitch error which is within the accepted range of a common tuner. Our .1% limit may have been too stringent.• The discrete frequency output may have a different timbre than the continuous frequency output. A wave-shaping circuit could be added to give them similar
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