[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PSUBS-MAILIST] Directional Hydrophone Array

Peter,
 
    It appears that you can construct an object detection system capable of receiving and processing an omnidirectional signal and two directional signals to produce a digitized omnidirectional signal, and digitized directional signals which have been corrected to magnetic north. The directional hydrophones produce sin .theta. and cos .theta. signals, where .theta. is the bearing angle of the sensed target from the directional hydrophones' y-axis.
    Each of the three signals is picked up by a separate hydrophone and is passed through an associated preamplifier and a shaper amplifier and low pass filter before being simultaneously sampled by separate sample/hold circuits. The three sampled signals are multiplexed to an analog to digital converter. The signal produced by a digital magnetic compass is converted to sin .theta. and cos .theta. values by appropriate function generators, where .theta. is the angle between the y-axis and magnetic north.
    The digital sin .theta., cos .theta., sin .phi. and cos .phi. signals are the multiplied together in a multiplier and the products placed in separate registers and added or subtracted by an adder to produce directional signals corrected to magnetic north according to the formulas sin .theta. cos .phi. - cos .theta. sin .phi. = sin (.theta. - .phi.) and cos .theta. cos .theta. + sin .theta. sin .phi. = cos (.theta. - .phi.).
    The corrected directional signals are then multiplexed together with the omnidirectional signal and a synchronization word and passed through an encoder to a transmitter for transmission to a distant receiver for processing and analysis.
   
Is this what you're looking for, or do you just want to go out and purchase something =)
 
Ken
 
 

Ahhh...imagining that irresistible "new car" smell?
Check out new cars at Yahoo! Autos.