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:
Apr. 30, 1991
Filed:
Jun. 30, 1989
John D Todd, Falmouth, MA (US);
Ferranti O.R.E. Inc., Falmouth, MA (US);
Abstract
A gain-controlled amplifier (24) in a sonic flow meter accepts an output signal from each transducer of a plurality of pairs of transducers (1a, 1b; 2a, 2b; 3a, 3b; and 4a, 4b) in sequence. A ramp generator (62) generates a time-varying-gain output, which increases between the transmission of a pulse by one transducer and the reception thereof by another. This time-varying-gain signal is one component of the amplifier's gain-control signal, which includes as another component an AGC value fetched from a memory (50) and rendered into analog form by a digital-to-analog converter (42). The value in the memory (50) is the difference between the time-varying-gain value and the value that other circuitry (30, 36) has determined to be necessary by monitoring the amplifier output produced during a previous operation of the same transducer pair. A third component of the gain-control signal is provided by further circuitry (40, 72, 76, 102), which acts to reduce the gain-controlled value if it determines that noise is present. It concludes that noise is present if the receiving transducer produces signal magnitudes that exceed a predetermined threshold before sound is expected from a transmitting transducer.