Hydrophones ( Process Analysis )
A procedure is an activity which occurs over clip and has clear end associating to the result to be achieved. It ‘s hierarchal because may dwell of sub-processes ( Muller 1 ) . Indentifying boundaries is of import when understanding a procedure i.e. its beginning and terminal. The beginning of a procedure is when a trigger causes some action to be taken by a group, individual or another procedure. On the other manus, stoping takes topographic points topographic point when the results are passed on to a group, procedure or another individual. Hydrophones they are low frequence piezoelectric underwater acoustics transducers. In other words they are mikes that operate under H2O ( Dolphinear.com 1 ) . They are designed from particular stuffs called piezoelectric because sound transmittal through H2O is different from transmittal through the air ( Caruthers 16 ) . Piezoelectric stuffs generate little electromotive forces when agitated or deformed.
Hydrophones work on the rule that when a sound moving ridge from a peculiar beginning hits the piezoelectric stuff, it builds-up emphasiss on the stuff which are subsequently transformed into a signal ( electrical ) . The produced signal is so amplified ready to convey into a set of earpieces, external talker or a tape recording equipment. One thing to observe about the hydrophones is they have to give the same frequence response which means they produce equal electromotive force sums per the measure of acoustic agitation despite the frequence. To accomplish this, piezoelectric stuff is mounted on a backup with the same or higher acoustic electric resistance and the terminal it with high electrical electric resistance. With these boundary conditions, the piezo outputs the electromotive force which is relative to coerce input. This technique consequences in the coveted level frequence response. Low frequence public presentation of the hydrophones tends to be limited by the electrical burden electric resistance taking to a simple RC clip changeless. Hydrophones are usually used below their resonance frequence and a broad frequence set where unvarying end product degrees are produced.
For proper operation of the hydrophones, they must be able to digest shipboard maltreatment ; they should besides be capable of defying corrosion, bio-fouling and besides high hydrostatic force per unit area. Reliability is so indispensable with hydrophones because frequent reviews can non be achieved. It is a good pattern to screen hydrophones from isolated electrical Fieldss which is done through utilizing a screen-like metal grid which is made to environ the detection component and shield the preamplifier. Modern hydrophones use independent internal shielding for the detector component and the subsidiary circuits. The external shield is electrically insulated from the metal lodging which is water-exposed. In kernel, preamplifier drivers are preferred to the inexpensive transformer-coupled systems because the transformer-coupled systems have more limited frequence responses which is a desirable component when planing a dependable and a functional hydrophone. For a well designed hydrophone, a preciseness of 10-ohm resistance in series with a detector for distant standardization intents is provided ( Caruthers 52 ) .
Caruthers, J.Fundamentalss of Marine acoustics. Elsevier, 1977.
Dolphinear.com.Underwater mikes – hydrophones, 2000. Retrieved February 27, 2010, from hypertext transfer protocol: //www.dolphinear.com/data/underwater_microphones.htm
Muller, G.What is a Procedure?, n.d. Retrieved February 27, 2010, from hypertext transfer protocol: //www.gaudisite.nl/WhatIsAProcessPaper.pdf