Abstract: A sonar sensor comprising a substantially non-corrodible housing and a fluidic gainblock disposed therein. In addition, one or more fluid-filled laminar proportional amplifiers are arranged either in series or in parallel and contained within the fluidic gainblock. Means are provided to produce a jet within each laminar proportional amplifier, which is then modulated by incoming acoustic signals. The pressure caused by diverting the jet from its equilibrium path is proportional to, but greater than, the incoming acoustic signal. Hydrophones are used to convert the amplified acoustic signal into an electrical signal. In one embodiment, the fluidic gainblock is free-flooded and open to the liquid environment in which it is used, obviating the need for pressure equalization. In another embodiment, the fluidic gainblock is provided with filtering means for prevent the accumulation of sediment within the cavities making up the laminar proportional amplifiers.

Abstract: A heart-sound monitor and esophageal stethoscope which makes use of fluidic aminar proportional amplifiers (LPAs). These LPA's are used to sense and amplify incoming acoustic pressure signals, such as heart signals. Moreover, the fluidic monitor is able to monitor a fetus heartbeat while eliminating the acoustic interference present from the mother's heartbeat. In this case, the LPA acts not only as an amplifier, but as an acoustic filter as well.

Abstract: An acoustic detection device having a parabolic dish antenna for gathering ound waves and providing a first stage of amplification, an exponential horn located at the focus of the parabolic dish antenna for further acoustic amplification, a fluidic gainblock for a final stage of amplification, and acoustic earphones for listening. Either a hand operated latex bulb or a mechanical pump is used to pressurize a plastic fluid storage container that is used to supply fluid to the fluidic gainblock. Within the fluidic gainblock are four or more staged laminar proportional amplifiers having a bandwidth of 0 to 4,000 Hz.

Abstract: A method for attenuation of low frequency acoustic sound in an acoustic dctor comprising the steps of collecting incoming sound waves in the frequency range of DC to 3000 Hz so as to provide an incoming signal S.sub.I, splitting the incoming signal into two signals S.sub.1 and S.sub.2 such that signal S.sub.1 travels through a one acoustic transmission tube a distance of L.sub.1 to the first control port of a fluidic laminar proportional amplifier and signal S.sub.2 travels through a second acoustic transmission tube a distance of L.sub.2 to the second control port of the fluidic laminar proportional amplifier, adjusting the L.sub.1 distance such that the phase of input signal S.sub.1 is shifted in relation to the phase of input signal S.sub.2 when input signals S.sub.1 and S.sub.2 arrive at the control ports of the laminar proportional amplifier.

Abstract: A full wave fluidic rectifier which produces a direct fluidic output signal having an amplitude which increases from a very low level as the amplitude of an alternating fluidic input signal increases. In includes a nozzle for directing a fluid stream along the rectifier axis into a null venting outlet, two signal outlets which are symmetrically disposed in opposite sides of the null outlet, and two control signal inlets for applying the alternating input signal to the stream, deflecting the stream alternately toward the two signal outlets in proportion to the amplitude of the alternating input signal. The two signal outlets are connected by respective channels of equal fluid resistance to a common channel which serves as the rectifier output.