THEREMIN

1
THEREMIN
Theremin

• Department of Electrical and Computer Engineering

2
Background
Theremin

• Created by the Russian Inventor Leon Theremin in
  1919.

• First electronic instrument influencing Moog and
  pioneers in musical electronics.

• The thereminist does not actually touch the
  theremin except to mute it.

• Controlled by capacitance between hands to
  antennas. Placement of the hands relative to
  antennas controls pitch and volume.

3
Motivation
Theremin
Continuous Pitch The theremin is a continuous
pitch instrument like trombone or violin which
makes staying in tune difficult. Also the lack of
any physical reference makes playing difficult to
learn.
Continuous Volume Staccato playing or quick
stops and starts are difficult with the theremin
because of continuous volume control.
Lack of Reference Since the thereminist does
not actually touch the theremin, he has no point
of reference for tuning notes and nothing to
steady his hand.
4
Solutions
Theremin
Dual Mode Theremin A more versatile theremin
will be able to switch from the original
continuous frequency mode and a new discrete
frequency mode that produces scales automatically.
Foot Pedal A foot pedal will allow
instantaneous mute and unmute in order to produce
easier staccato.
Tuning A reference for tuning will be provided
for silently locating starting pitches and pitch
verification during practice. Theremin will
interface with common tuners.
5
Design Requirements
Theremin

• Discrete Frequency Accuracy
• Switchable between playing the traditional
  continuous range and playing only distinct
  frequencies in twelve selectable major scales
  with error lt 0.1.

• Precise Articulation
• A footswitch will connect to the theremin to
  enable the performer to quickly and easily
  articulate notes.

• Tuning
• A 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.

• Frequency Range
• A frequency range of four octaves with a center
  frequency at 440Hz.

6
Design
Theremin
3. Update Simulations
7
Theremin Modular Design
Theremin
V/F Converter
Freq Switch
Audio Out
Tuner Out Signal
Footswitch
8
Front Panel Frequency Controls
Theremin
Key
Continuous
A
B
Chromatic
b

C
G
F
D
Discrete
E
9
Tuning
Theremin
FLAT IN TUNE
SHARP
A . B C . D . E F .
G .
Sabine STX-1100
Theremin
10
Conclusions and Future Work
Theremin

• Our .1 pitch error limit may be more stringent
  than needed. Some common tuners accept up to .2
  pitch error.

• 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 quality.

11
Time Line
Theremin
Semester One
Month 1 Month 2 Month 3 Month 4




Requirements
Test Certification
Test Specification
Design Document
Simulation
Semester Two
Month5 Month 6 Month 7 Month 8




Final Design Document
12
THEREMIN
Theremin

• Department of Electrical and Computer Engineering

13
Test Specification
14
Discrete Mode Overview
Theremin
110-1760 Hz continuous beat frequency from
detector
0.3-5 V continuous voltage range
Voltage/Frequency Converter
Binary representation of selected output level
Resulting discrete voltage level
Desired note within 0.045 error