everywhere over the submerged portion of the ship. The patent concerns a second carriage which measures the position of the camera, and is con- strained to travel along a line parallel to the ship's axis. Using the time of travel of ultrasonic pulses in the water, it measures its own position along its line of travel, and measures the distance of the camera from that line. Thus the x and y coordinates of the camera are always known. No details of the ultrasonic system are given in the patent.mLB

4,308,601

4,311,157 43.35.Ty SONIC TREATING APPARATUS

Duncan B. Jubenville and Melvin G. DeGrazia, Jr., assignors to Rock Oil Corporation

19 January 1982 (Class 134/125); filed 26 February 1980

Sheets of steel to be cleaned, pickled, phosphated, or whatever, are carried through an acid bath on plastic sprocket chains 41, 42, and 43. A number of transducers 33, on both sides of the tank, vibrate the liquid

43.30.Vh ECHO RANGING APPARATUS AND METHOD

William E. Lahr, Compton, California, •si•or in part to David R. Plotkin, Redondo Beach, California

29 December 1981 (Cica 367/115}; filed 27 January 1980

This apparatus is a recording depth sounder particularly adapted to . .•••o

display echoes from fish in a background of vegetation. The novel feature is a "signal modifier" that is designed to enhance the display of echoes. It takes effect only when an echo reaches a certain threshold. When this occurs, it waits for several milliseconds to allow the echo to be recorded, and then reduces the signal voltage at the recording stylus to avoid excessive blacken-

ing of the chart. Consequently, echoes from fish and from the top surface of • N• W•VO•

*•:.:;g •,;".,'•:•,'•;•.v"' '•. "..' •' • ' •"•':'"/U, • r ': "•':

..... spro., han. which pass,hrou,h,h.a,h,o supr,,h. sh.,s .... ,,:,'..,' ,,,- ?.'•.• ........ , .,• ....... ,•.'..••, ..'.','• .... :'• horizontally at about 25 kHz. The patentable novelty s•ms to be the • ...., .. :'• . .",</. s. ,. •:..' ......:,;,, • v "•"q:J'•'L'•¾":' '"

the bottom stand out more clearly. This sample recording was made with a dry paper recorder, which is incorrectly called electrochemical in the pat- ent. The fish echoes stand out clearly, even when the fish are near the bot- tom. In the shoalest region, vegetation is visible in the second and third echoes, but has been eliminated from the first bottom echo by the signal modifier.--LB

4,310,905 43.35.Sx ACOUSTICAL MODULATOR FOR FIBER OPTIC TRANSMISSION

John P. Palmer, assignor to General Dynamics 12 January 1982 (Class 367/140); filed 20 February 1980

The light that comes out from an optical fiber 40 is reflected by the surface 42, but because of divergence, only a fraction of it re-enters the fiber and travels back to a light detector at the other end. If the surface 42 is the back of a diaphragm on which sound impinges, the diaphragm will vibrate

and vary the distance h so as to modulate the amount •of light that travels back to the detector. A microphone or hydrophone can be made to operate in this way, but no practical embodiment is described. However, it is stated that, depending on the types of light source and light detector that are used, a sensitivity in the order of 20 to 1000 mV per pm of diaphragm displace- ment is possible.--LB

4,305,294 43.35.Yb ULTRASONIC APPARATUS AND METHOD FOR MEASURING WALL THICKNESS

Carmine F. Vasile and Robert B. Thompson, assignors to Rock- well International Corporation

15 December 1981 (Class 73/579); filed 10 January 1980

A method is disclosed "for determining the thickness of an object, including the steps of generating a higher order mode ultrasonic wave at a first location on the object, varying the frequency of the generated wave, and measuring, at a second location on the object, the minimum frequency at which the generated wave will propagate in the object. Where the ultrasonic wave generated is a horizontally polarized shear wave, the thickness t may be calculated from the relationship t = (n Vs/2fc ), where n is the wave mode

14

RECOROER T "58 ]• xo•• ••'•

number, Vs is the shear wave velocity, andfc is the minimum propagation frequency. Alternatively, the steps may be repeated for the next consecutive frequency minimum and the thickness t calculated from the formula

1092 J. Acoust. Soc. Am. 72(3), Sept. 1982; 0001-4966/827091092-02500.80; ̧ 1982 Acoust. Soc. Am.; Patent Reviews 1092

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 134.225.1.226 On: Sat, 20 Dec 2014 13:37:18