Abstract: The alternative power system provides microprocessor grade, filtered output power capable of replacing standard NiCad battery packs in portable electronic devices. The invention makes use of capacitor banks comprised of capacitors having different values, whereby the individual capacitors act as individual filters to substantially eliminate all transients which are present in the source of power, which is typically provided by rechargeable batteries on a host system, such as a forklift or hand truck.

Abstract: A U.S. Coast Guard approved personal flotation device for persons engaged in sport activities. The personal flotation device includes a body formed from a series of body panels, or sections, formed from a fabric covered soft foam flotation material. Elastic armhole periphery members are attached about the armholes of the PFD intend to engage the shoulders and upper arms of the wearer. The armhole periphery members are formed from an elastic, stretchable material so as to enable the armhole periphery members to flex and conform to the shoulders and upper arms of the wearer as the arms, shoulders, and upper torso of the wearer move while the wearer performs water sport activities. This allows the PFD to move and conform to the body of the wearer for enhanced comfort and increased ability of the wearer.

Abstract: An improved display fixture having removable retaining arms is provided. The fixture allows the user to quickly and easily replenish the fixture with display items, such as eyeglasses, while also providing the user with the ability to readily alter the location of items on the fixture. The display fixture is provided with retaining arms which are compatible with the desired display merchandise. The retaining arms are readily removable from and replaceable on the display fixture in user desired locations. In accordance with the invention, the retaining arms have at least one leg which is fitted into an opening formed in a medium density fiberboard backboard.

Abstract: A substantially rectangular, protective drape which is selectively attachable to a hard hat, preferably includes a strip of "hook and loop" fastener along one edge. A complementary strip of "hook and loop" fastening material is attached to the inner wall of the hard hat. The drape is used to protect the neck and, selectively, the ears, of the user from the elements.

Abstract: The present invention uses molded components to receive the ends of electrical zip cord. Elongated contact pins which are molded into the components are inserted axially into the ends of the stranded conductors at the end of the zip cord making positive electrical contact to the conductors. Ridged portions within the molded components receive, grip, and retain the insulator on the outer portion of the zip cord, thereby separating the functions of electrical gripping and mechanical contact in the present invention.

Abstract: The present invention is a real time digital encryption system which may be implemented in either hardware or software. The encryption system uses keys and an algorithm in which the encryption is determined in part by the data being encrypted, to obtain a scramble which is uniquely determined by the combination of the encryption keys and the data being encrypted, thereby making any effort at cryptanalysis extremely difficult, if not impossible. Consequently, anyone seeking to decrypt the data encrypted by the present invention would have to resort to an extensive brute force approach to such decryption efforts.

Abstract: An electricity metering device including at least one sigma-delta converter (20) adapted to output a series of digital pulses, a digital counter means (21) for summing the output of the sigma-delta converter and a signalling means (32) to deliver an output signal (38) when the sum reaches a predetermined value, characterized in that the metering device further comprises a means (32, 33) for digitally adjusting the gain of the sigma-delta converter comprising programmable digital memory means (33) adapted to store a parameter representing the gain of the metering device, the value of the parameter being externally programmable, and a digital logic means (32) for logically combining the gain parameter with the digital sum stored in the counter means to determine the number of pulses required before the predetermined value is reached and an output pulse delivered.

Abstract: A device for detecting tampering of a utility meter includes sensors to detect a positional displacement of the meter and loss of power to the meter. On sensing a positional displacement of the meter, indicative of an attempt to remove the meter, a timer is activated to enable sensing a power loss to the meter. In response to detection of a power loss during the time period defined by the timer, an indication is stored in a nonvolatile memory of the tamper event. In response to loss of power with or without a detection of tampering, required parameters including utility consumption data are stored in nonvolatile memory. Remote access to and data retrieval from the nonvolatile memory and system are provided over telephone lines, power lines, or a radio frequency circuit.

Abstract: An apparatus for monitoring the state of operation of lamp (2) in a public lighting network is provided comprising a sensing unit (6) associated with each lamp (2) for measuring the voltage of and luminous flux emitted by each lamp (2). Each sensing unit (6) also calculates the efficiency of lamp using an efficiency index given by the gradient of the line which, in a Cartesian diagram in which the voltage of the lamp is the x-coordinate and the flux the y-coordinate, represents the instantaneous relationship between the parameters.

Abstract: An integral electronic meter system diagnostics package including a microprocessor, storage memory, logic for automatically and periodically performing a pre-select series of system diagnostic tests, and recording any results which exceed predefined programmable thresholds, and display means for displaying error and/or diagnostic messages identifying selected diagnostic data and/or errors discovered in the meter tests during a predefined period.

Abstract: An integral electronic meter system diagnostics package including a microprocessor, storage memory, logic for automatically and periodically performing a pre-select series of system diagnostic tests, and recording any results which exceed predefined programmable thresholds, and display means for displaying error and/or diagnostic messages identifying selected diagnostic data and/or errors discovered in the meter tests during a predefined period.

Abstract: An impeller for a fluid meter, the impeller comprising a bearing including a central recess suitable for receiving a pivot, and including at the periphery of the central recess, open-ended fluting with adjacent flutes being separated by ribs. Axial passages are distributed around the fluting, with each passage co-operating with at least one flute in such a manner as to facilitate a flow of fluid via the passage to the detriment of a flow of the fluid along the flute. The impeller is applicable to metering fluids loaded with particles in suspension.

Abstract: A system for detecting the presence of an average dc current component in a load comprising a current transformer 10 for supplying a signal representative of the current, and a comparison means 12 and 13, for example a microprocessor and associated RAM, for comparing values of the current taken at time intervals corresponding to a phase interval of substantially n.pi., where n.pi. is an odd integer, of the ac periodic supply signal, so as to determine the presence of a dc current component caused by rectification of the supply. In one embodiment, the signal from a voltage detecting means 14-18 can be used to synchronise the sampling of the current at the correct phase.

Abstract: A modulated integrator circuit frequency modulates an input signal and has an integrator comprised of an amplifier (31) and an intregrating capacitor (35) connected across an input and an output of the amplifier. The circuit further comprises a storage capacitor (36) in addition to any switching capacitors (C) associated with the modulation of the input signal if present. The storage means (36) is connectable between the input and the output of the amplifier in parallel with the integrating capacitor. The storage capacitor stores a charge associated with the voltage of the output of the amplifier and transfer such charge to the integrating capacitor to enable reversal of the charge of the integrating capacitor in synchronism with the frequency modulation of the input signal.

Abstract: The RF meter reading system includes a transmitter having an encoder. Meter data is encoded and modulated using a bi-phase modulating scheme. In order to uniquely identify the start of a data transmission, a super start field, which is an "illegal" bi-phase signal is used. The super start field is selected such that it cannot be recognized if transmissions from more than one transmitter are being received by the receiver.

Abstract: A system for analogue to digital conversion comprising a means (4) for receiving an input analogue signal, a dither generator for adding a dither signal and an analogue to digital converter (2) for converting the combined input signal and dither signal to a digital value, characterized in that the dither generator provides a dither signal of a form comprising a first periodic dither signal having superimposed and being shaped by a second signal having at least one component which varies the first periodic dither signal over at least one quantization interval of the analogue to digital converter.

Abstract: A Hall effect sensor of two-dimensional electron gas type comprising, on an insulating substrate, a quantum well structure, a carrier injection layer adjacent to the quantum well structure, of thickness less than 250 .ANG. and having an density per unit area of donors integrated over the whole thickness of the carrier injection layer less than 5.times.10.sup.12 cm.sup.-2, an insulating burial layer deposited on the carrier injection layer, having a conduction band with an energy level greater than the Fermi energy of the sensor and a thickness greater than 200 .ANG.. Applicable to the field of electricity meters and current sensors.

Abstract: A Coriolis-type fluid flow rate measuring system splits a fluid flow that is to be measured into two equal half flows and passes the same respectively through two physically similar conduits which are oscillated about respective parallel oscillation axes. Analog sinusoidal signals corresponding to relative velocity of motion between the two conduits are obtained at two locations, the analog signals a digitized, and a conventional microprocessor is used to apply a least-squares sine fit to the digitized data to determine to a very high degree of accuracy a phase shift between the signals. An empirical proportionality factor is determined for the system to relate phase shift to fluid flow rate and is used to determine the fluid flow rate. The least-squares sine fit provides an accurate, economically computed fluid flow rate, and the apparatus is highly insensitive to temperature induced effects, harmonic distortions, and the combined effects of noise and harmonic distortion.

Abstract: A secondary communications device, such as a modem, a facsimile machine, an automatic meter reader or an answering machine, shares a telephone line with a subscriber's telephone and must grant the telephone primary access to the line. The present invention prevents the secondary device from seizing the line when the telephone is already off-hook and will terminate a line seizure by the secondary device if the subscriber picks up the telephone handset during use of the line by the secondary device. An average interval for charging a capacitor to a threshold voltage in response to an on-hook voltage appearing across the telephone line is determined. When the secondary communications device is ready to use the line, circuitry measures an interval for charging the capacitor in response to the current voltage appearing across the telephone line. The secondary communication device seizes the line only if the measured interval does not exceed the average interval by more than a predetermined amount.

Abstract: A method and system is disclosed for indication and prevention of tampering with an electricity meter having control circuitry for automatic remote reading. The control circuitry, provided externally of the meter in a base or base extension, to which the meter is connected, is also used for tamper detection. Embodiments of the invention include use of optical sensing, voltage detection and proximity detection. Ambient light sensing may be performed to detect separation of the meter from the external receptacle. Reflected light to a reflective surface of the meter is sensed to determine if the meter is properly engaged. Presence of a meter connection plug element may be sensed either optically or by position responsive switch. Voltage of the utility supply and meter user output may be monitored to determine tampering.