Method and device for determining the tonality of an audio signal

US5918203A · kind A · utility

Assignee

• Max-Planck-Gesellschaft zur Föderung der Wissenschaften e.V. · US

Inventors

• Jürgen Herre · Buckenhof, DE
• Ernst Eberlein · Erlangen, DE
• Bernhard Grill · Lautenbächle, DE
• Karlheinz Brandenburg · Erlangen, DE
• Heinz Gerhauser · Waischenfeld, DE

Key dates

• Filing date: Aug 13, 1997
• Grant date: Jun 29, 1999
• Expiry date: Aug 13, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03G5/005
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

The tonality of an audio signal is determined by a method which includes the steps of blockwise frequency transforming a digital input signal x(n) to create a real positive-value representation X(k) of the input signal, where k designates the index of a frequency line, and determining the tonality T of the signal component for the frequency line k according to the following equation: ##EQU1## where F.sub.1 is the filter function of a first digital filter with a first, differentiating characteristic, F.sub.2 is the filter function of a second digital filter with a second, flat or integrating characteristic or with a characteristic which is less strongly differentiating than the first characteristic, and d.sub.1 and d.sub.2 are integer constants which, depending on the filter parameters, are so chosen that the delays of the filters are compensated for in each case.