Filter circuit
US6212540A · kind A · utility
Inventors
Key dates
| Filing date | Aug 3, 1998 |
| Grant date | Apr 3, 2001 |
| Priority date | — |
| Expiry date | Aug 3, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/02
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A filter circuit is provided for two-axis signals which has good filtering characteristics such as steep filter characteristics in a narrow bandwidth without transformation from a stationary coordinate system into a rotating coordinate system and vice versa. Input signals related to orthogonal two axes are represented by a complex variable (U=Ux+jUy: Ux, Uy are respective quantities of Laplace transformation), and a transfer function of a lowpass or highpass filter of real coefficients is represented by F(s). A complex coefficient transfer function produced by replacing the Laplace operator "s" in the transfer function F(s) with "s-j.omega." is represented by F(s-j.omega.). When the input complex variable U is passed through the complex coefficient transfer function F(s-j.omega.), an output signal related to orthogonal two axes is expressed by a complex variable (V=Vx+jVy: Vx, Vy are respective quantities of Laplace transformation), and a transfer representation equation is expressed by U F(s-j.omega.)=V. Connections are made with a transfer element of real coefficients in order to equalize real and imaginary parts of the transfer representation equation after both sides of the tra…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.