AN INTEGRATED-CIRCUIT PIANO TUNER FOR THE EQUAL-TEMPERED KEYBOARD EMPLOYING A TUNEABLE FIXED-COEFFICIENT DIGITAL FILTER.

Abstract

A study of the physics of the piano reveals that while the upper partials of the steel strings are the eigen-frequencies of the complex tone, they are not integer multiples of the respective fundamentals. To properly measure and tune these eigen-partials, a digital filter capable of sweeping a major portion of the audio-frequency spectrum had to be implemented. Such a filter, a tuneable fixed-coefficient digital filter, is discussed as well as a simple pole-zero design procedure for determining the required coefficients. Each module, including the frequency deviation detector and counter, the time-base generator, the digital filter, the reference frequency generator and the display and control module, of the proposed tuner is illustrated and discussed. (Author)

Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1969
Accession Number
AD0703640

Entities

People

  • Michael William Hagee

Organizations

  • Naval Postgraduate School

Tags

DTIC Thesaurus Topics

  • Audio Frequency
  • Circuits
  • Coefficients
  • Detectors
  • Digital Filters
  • Filters
  • Frequency
  • Generators
  • Integrated Circuits
  • Keyboards
  • Spectra

Readers

  • Approximation Theory.
  • Control Systems Engineering.
  • Electronics Engineering