The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 23, 1997
Filed:
Sep. 10, 1996
Chien-Ping Wu, Taipei, TW;
Chang-Da Tsai, Taipei, TW;
National Science Council, Taipei, TW;
Abstract
A second-order highpass difference filter constructed according to the present invention includes a difference amplifier and a feedback processing circuit. The difference amplifier includes an operational amplifier OP.sub.1, and four resistors R.sub.1, R.sub.2, R.sub.3 and R.sub.4. The feedback processing circuit is composed of two operational amplifiers OP.sub.2 and OP.sub.3, resistors R.sub.5 and R.sub.6, and two serial capacitors C.sub.1 and C.sub.2. The inverting and noninverting terminals of the operational amplifier OP.sub.3 are connected to the output of the difference amplifier and of the operational amplifier OP.sub.2, respectively. The output of the operational amplifier OP.sub.2 is also fed back to the inverting terminal of the operational amplifier OP.sub.2 via the resistor R.sub.5, and the noninverting terminal of the operational amplifier OP.sub.2 is grounded. The output terminal of the operational amplifier OP.sub.3 is connected to the inverting terminal of the operational amplifier OP.sub.2 via the two serial capacitors C.sub.1 and C.sub.2 and to the noninverting terminal of the operational amplifier OP.sub.1 via the resistor R.sub.4. The two serial capacitors C.sub.1 and C.sub.2 are connected therebetween to one terminal of the resistor R.sub.6 of which another terminal is grounded.