Abstract: An anchor protector attaches to a protruding stock of a boat anchor and minimizes damage from impact with the protruding stock. The anchor protector is buoyant and can accommodate the protruding stock of various diameters.

Abstract: An anchor protector attaches to a protruding stock of a boat anchor and minimizes damage from impact with the protruding stock. The anchor protector is buoyant and can accommodate the protruding stock of various diameters.

Abstract: A system and method that facilitate efficient use of 3G high-speed data networks while providing for personalized audio content selection and coordinated distribution of selected content are disclosed. The invention categorizes audio content to be delivered over wireless networks such that the categories correspond to a different delivery priority. In an illustrative three-category implementation, category 1 content has the highest delivery priority for delivery as soon as possible, category 2 content has the next highest delivery priority for delivery, and category 3 content, such as music, audio books and so on, has the least urgent delivery priority. The categories are used to coordinate audio content delivery to efficiently use available bandwidth and network resources by delivering content at off-peak times. The invention also allows the downloading process to be interruptible such that it can be resumed at about the point of an interruption to conserve resources.

Abstract: A second-order differential (SOD) microphone includes a first-order differential (FOD) microphone element installed in a housing. A pair of front sound conduits extend from respective ports to a chamber on the front side of the microphone diaphragm, and a pair of rear sound conduits extend from respective ports to a chamber on the rear side of the microphone diaphragm. The two front ports and the two rear ports are all substantially collinear along a minor axis, with the rear ports intermediate the front ports or the front ports intermediate the rear ports. The respective acoustic transfer functions from each port to the microphone diaphragm are equivalent. The microphone response is approximately proportional to the second spatial derivative, along the minor axis, of a sample acoustic pressure field.

Abstract: A second-order differential (SOD) microphone includes a first-order differential (FOD) microphone element installed in a housing. A pair of front sound conduits extend from respective ports to a chamber on the front side of the microphone diaphragm, and a pair of rear sound conduits extend from respective ports to a chamber on the rear side of the microphone diaphragm. The two front ports and the two rear ports are all substantially collinear along a minor axis, with the rear ports intermediate the front ports or the front ports intermediate the rear ports. The respective acoustic transfer functions from each port to the microphone diaphragm are equivalent. The microphone response is approximately proportional to the second spatial derivative, along the minor axis, of a sampled acoustic pressure field.

Abstract: A radio or telephone handset configured with the usual transmitter and receiver ends and connecting handle is designed to have physical characteristics well adapted in its acoustic characteristics to complement noise cancellation circuitry. The receiver speaker is mounted in the receiver cap, and the cap is built with a domed, apertured earpiece extending from the exterior surface of said receiver cap. The dome fits into a user's outer ear, thereby to aid in positioning said handset on a user's ear. Openings radially placed on said receiver cap exterior surface and surrounding said earpiece, define an acoustic grill through which signal from said receiver speaker is passed substantially directly to said user's ear canal. Noise absorbing material is placed at strategic locations within the handset interior.

Abstract: Improved microphone performance is achieved by configuring a second-order derivative microphone assembly in such a way that radially divergent near-field input produces a microphone response proportional to a first-order spatial derivative of the acoustic pressure field.

Abstract: Telephone headsets used by operators and airline pilot headsets are subject to substantial amounts of interfering ambient noise which detract from the intelligibility of incoming speech. Noise reduction circuitry does not altogether eliminate the interfering sound. A headset speaker and error microphone housing are disclosed which enable a greater amount of unwanted noise elimination. The speaker and microphone are configured closely with respect to each other and also to the user's ear. They are acoustically isolated in their own chamber. The microphone is located approximately on the speaker axis and protrudes substantially into the user's ear; and also is disposed close to the speaker cone surface. Additional acoustical tuning features include venting ports in the housing, and acoustic damping padding at the microphone entrance and on either side of the speaker. These expedients enhance the ability of the noise-cancelling circuitry to effectively reduce the undesired noise heard by the user.

Abstract: In an active control noise-cancelling muffler system, a substantially complete acoustic and mechanical decoupling of the noise-cancelling signal pipe from the gas exhaust pipe is achieved. The noise-cancelling signal delivery pipe is physically isolated and separate from the gas exhaust pipe, and is mounted separately. The outlet end of both pipes are essentially coplanar. Using pressure sensors on the tubes, the system also accurately and continuously electronically replicates the mixing of the exhaust noise and the noise-cancelling acoustic energy that goes on in the space immediately beyond the two outlets. This electronic signal is a useful alternative for a direct measure of the resultant two acoustic waves when they mix in the space beyond the tube outlets, and allows the system to continuously estimate the degree of success of noise cancellation without having to measure it directly when impractical.

Abstract: A magnetically actuated safety receptacle and plug characterized by a receptacle having a first pair of electrical contacts extending through a support member, and an over-center drop-out member hinged to the support member and carrying a second pair of electrical contacts. When a magnetic plug is inserted into a recess provided in the front of the support member the drop-out member is magnetically attracted towards the support member so that the first pair of electrical contacts and the second pair of electrical contacts abut to provide power to the plug. The hinge attaching the drop-out member to the support member is articulated so that the contacts can wipe against each other to remove any oxide build up. An industrial version of this invention includes a gas tight enclosure surrounding the drop-out member and the interior contacts to prevent accidental ignition of combustible gases.