Digitally programmable linear phase filter having phase equalization
US5245565A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 1991 |
| Grant date | Sep 14, 1993 |
| Priority date | — |
| Expiry date | Jul 31, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/1258
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digitally programmable Bessel filter includes a plurality of serially connected stages or biquads with each biquad including a plurality of programmable operational transconductance amplifiers. The first stage of the filter provides an all pass equal amplitude response. Two stages provide pulse slimming (first and second derivatives of an input pulse), and three stages provides a sixth order Bessel low pass function. The operational transconductance amplifiers are controlled by a fine tuning control signal, and an array of integrating capacitors are selectively controlled by a coarse tuning signal. The fine tuning and coarse tuning signals are generated in a phase locked loop from a reference clock and a reference biquad which receives the reference clock.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.