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:
Aug. 04, 1987
Filed:
Apr. 03, 1985
Michael J Gill, Milford-on-Sea, GB;
Brookes & Gatehouse Limited, , GB;
Abstract
A speed measurement device for measuring the speed of a ship through the water is disclosed. The device comprises a transmitter circuit and a receiver circuit connected to two transducers T.sub.1, T.sub.2 which are based substantially in the direction of travel of a ship below the water line thereof. Pulse trains are transmitted in both directions between the transducers T.sub.1, T.sub.2 which are received by the receiver circuitry so that a signal is derived indicative of the time taken for the signals to travel both for and against the direction of travel of the ship, this signal being proportional to ship's speed. The device is designed to operate at a frequency of pulse transmission of 500 kHz and the receiver circuitry includes a variable threshold comparator 240, 250 and a divider circuit 260 for identifying a predetermined pulse in the developed part of the pulse train as received which allows accurate detection of the arrival time of the received pulse train at this frequency so that the transit time of the pulse train between the transducers T.sub.1, T.sub.2, and thus the speed of the ship can be accurately calculated.