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:
Sep. 20, 2005
Filed:
Apr. 26, 2004
Lars Jespersen, Soenderborg, DK;
Lars Jespersen, Soenderborg, DK;
Siemens Flow Instruments A/S, Nordborg, DK;
Abstract
A transmitting and receiving circuit for an ultrasonic flowmeter. In such circuits, an ultrasonic transducer is typically used as both transmitter and receiver. This is obtained by using switching means, for example in the form of CMOS switches. However, problems arise with ringings of a transducer when having acted as a transmitter. This unwanted ringing makes the crystal of the transducer act as an additional signal generator, and the signal is coupled via parasitic capacitances in a switching means to the receiving ultrasonic transducer. This problem is solved by connecting one pole of a short circuit switch (S, S) to the ultrasonic transducer (TR, TR) or to the switching means (S, S) and the other pole of the short circuit switch to ground. Keeping the short circuit switch closed when the switching means is open, and open when the switching means is closed, creates a decoupling path for the unwanted signal, thereby improving the accuracy of the transmitting and receiving circuit.