Device for obtaining harmonic-free signals

US5726445A · kind A · utility

Assignee

• DR. JOHANNES HEIDENHAIN GMBH · DE

Inventors

• Josef Thaler · Traunreut, DE
• Hermann Meyer · Schneizlreuth, DE

Key dates

• Filing date: Jun 21, 1996
• Grant date: Mar 10, 1998
• Expiry date: Jun 21, 2016

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/366
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A scanning graduation that scans a scale along a measuring direction to produce a signal representative of a position measurement value. The scanning graduation includes a particular transmission function which generates a filtering function when scanning the scale, wherein the transmission function is determined by a quantity of harmonics to be suppressed in the signal. The scanning graduation includes at least one scanning element for scanning a graduation period of the scale. The at least one scanning elements have at least one track comprised of N sub-elements, which are offset from one another in a measurement direction within a graduation period of the scanning graduation and whose effective widths b.sub.i (i=1 to N) within the graduation period are matched to their position within the graduation period so that the Fourier coefficients of the transmission function associated with the harmonics to be suppressed are minimized.