Abstract: An operating circuit (1) for controlling the speed of a cooling fan motor (3) for computer cabinetry (7), and for determining an under-speed condition in the fan motor (3) comprises a control circuit (15) which controls a variable output signal generator circuit (18) for outputting a pulse width modulated signal corresponding to the desired fan speed for switching a switching circuit (8) in a power supply circuit of the fan motor (3) for pulse width modulating the power supply to the fan motor (3). A monitoring resistor (R1), a capacitor (C1) and a circuit (12) provides a tachometer signal to the operating circuit (1). A gate circuit (22) gates the second and fourth pulses of the tachometer signal to a counter (20) which counts clock pulses from a clock signal generating circuit (19) between the rising edges of the second and fourth pulses which are in turn stored in a register (23) for comparison with a reference count by a comparator (25).

Abstract: A fan speed control system for an electronic equipment enclosure comprises means for determining temperature at a plurality of locations within the enclosure, means for determining operating parameters for the fan control system, means for setting operating speed of at least one cooling fan, and means for exchanging information signals relating to fan speed control system operation with an external controller. A method is also provided for controlling fan speed for an electronic equipment enclosure comprising the steps of determining temperature at a plurality of locations within the enclosure, determining operating parameters for the fan control system, setting operating speed of at least one cooling fan, and exchanging information signals relating to fan speed control system operation with an external controller.

Abstract: An IC monitoring chip (10) for remotely monitoring the output of a thermal diode (5) formed in the substrate of a CPU (2) for monitoring the temperature of a thermal plate (3) of the CPU (2) comprises a signal conditioning circuit (12) which relays the output from the diode (5) to an analog-to-digital converter (14), which in turns outputs a two's compliment signal to an adder (22). The adder (22) adds the two's compliment signal to a temperature offset value stored in a temperature offset register (17), which compensates for the temperature difference between the diode (5) and the thermal plate (3). Comparators (24) and (25) compare the output from the adder (22) with upper and lower predetermined temperature limits in upper and lower limit registers (19) and (20) for determining the temperature of the thermal plate (3). The temperature offset value is stored in ROM (35) of the computer (1) and is written to the register (17) each time the computer (1) is powered up.

Abstract: A switch in an optical network unit selectively couples line side ports of the line cards of the unit to individual line circuits in drop cable wiring extending to the customer premises served by the unit. The switchable optical network unit (SONU) permits rapid automated upgrades of service. For example, automatic switching of a line circuit to a line card offering an upgraded service together with automatic provisioning of the SONU to activate service through that line card provides the new upgraded service over the existing line circuit, without requiring a technician to install a new line card or manually connect the line card to the line circuit. If the drop cable to the customer premises includes a primary line circuit and an auxiliary line circuit, the line port can be switched over from the primary line circuit to the auxiliary line circuit to automatically restore service in the event of a failure of the primary line circuit.

Abstract: A decoupled switched current temperature circuit with compounded .DELTA.V.sub.be includes an amplifier having an inverting input with corresponding non-inverting output and a non-inverting input with a corresponding inverting output; a PN junction connected to the non-inverting input through a first input capacitor and a voltage reference circuit is connected to the inverting input through a second input capacitor; a current supply includes a low current source and a high current source; a switching device applies the high current source to the PN junction and applies the low current source to the PN junction for providing the .DELTA.V.sub.

Abstract: A switch in an optical network unit selectively couples line side ports of the line cards of the unit to individual line circuits in drop cable wiring extending to the customer premises served by the unit. The switchable optical network unit (SONU) permits rapid automated upgrades of service. For example, automatic switching of a line circuit to a line card offering an upgraded service together with automatic provisioning of the SONU to activate service through that line card provides the new upgraded service over the existing line circuit, without requiring a technician to install a new line card or manually connect the line card to the line circuit. If the drop cable to the customer premises includes a primary line circuit and an auxiliary line circuit, the line port can be switched over from the primary line circuit to the auxiliary line circuit to automatically restore service in the event of a failure of the primary line circuit.

Abstract: The drop wiring from an optical network unit (ONU) to a customer premise includes one or more working circuits and at least one auxiliary circuit. The network interface device at the customer premises is switchable. The interface device normally couples the working circuits to corresponding customer premises wiring circuits. The ONU and the switchable network interface device (SNID) can be automatically activated to activate communication via the auxiliary circuit. For example, if a primary telephone circuit fails or is predicted to fail, the ONU is automatically instructed to place the telephone communications on the auxiliary circuit, and the network instructs the SNID to connect the auxiliary circuit to the customer premises telephone wiring. The automatic activation and switching also facilitates automatic provision of a second line service using the auxiliary circuit.

Abstract: A digital signal processor for a PRML system includes: an NMOS pass transistors gain control circuit responsive to a digital data signal for adjusting the gain of the digital data signal; an NMOS pass transistor phase control circuit responsive to the digital data signal for adjusting the phase of the data signal; and an NMOS pass transistor Viterbi maximum likelihood detector circuit for determining the most probable sequence of symbols in the data signal.

Abstract: A method and apparatus for providing automatic frequency and voltage selection for microprocessors in a computer system. Microprocessor identification (ID) bits are burned into a microprocessor during manufacture to specify the correct bus frequency and core voltage. A clock generator and voltage regulator are provided to receive and interpret the ID bits and provide the correct frequency and voltage.

Abstract: The present invention relates generally to a new apparatus and a method for non-destructive inspection and/or measurement. And, more particularly, the invention encompasses an apparatus that has a flexible foil or membrane secured thereto which conforms to the surface of the part that is being inspected and/or measured in a nondestructive manner using differential pressure.

Abstract: An improved back gate switched sample and hold circuit includes a sample and hold channel including a sample switch having a back gate and a storage element; a back gate circuit for controlling the back gate of the sample switch; and a first attenuator circuit for scaling the input signal from a low impedance source for delivery to the sample switch and a second attenuator circuit responsive to the input signal from the low impedance source to independently drive the back gate circuit and isolate any distortion of the input signal in the back gate circuit from affecting the input signal in said sample and hold channel.

Abstract: A convertible carrying bag/envelope suitable for carrying and shipping printed materials and other items. The bag/envelope provides a handle that may be used to carry the bag/envelope while allowing items to be placed into or removed from the interior of the bag. The bag/envelope provides an exterior flap that is operative for sealing the bag, on which delivery indicia is printed, so that it may be shipped via a small package delivery service. To prepare the bag for shipping, the handle is folded into the interior of the bag. The flap is then extended across the opening and affixed to the opposite panel using the pressure-sensitive adhesive provided on the flap.

Abstract: A combined drill and underreamer tool capable of selectively drilling and underreaming a well hole on command, which includes a fluid distribution system wherein drilling mud under pressure is accumulated in a central chamber and from that central chamber a portion is distributed to the drill bit while another portion is distributed to the underreamer tool when that tool is operative, and, further, employing drilling mud under pressure to activate and deactivate the underreamer tool by selectively blocking and unblocking a fluid a passage thereto.

Abstract: A method is disclosed for remineralizing demineralized portions of teeth by treatment with a non-astringent composition containing about 10-20% xylitol, and at least one fluoride ion-providing compound in a total amount sufficient to provide about 150 ppm to about 1800 ppm of fluoride ions, with sodium fluoride providing a predominant proportion of such fluoride ions.

Abstract: An improved removable cooking surface assembly for the upper movable heated platen of a two-sided cooking device includes a cooking surface device having a planar rigid heat-conducting metal platen with threaded studs bonded to its upper surface, the studs being aligned with bores in an upper movable heat platen, the heat-conducting plate being coated on its lower surface with a layer of non-stick synthetic coating. The coated platen is removably connected with a heated platen and extends in contiguous relation across the lower surface of the heated platen for uniform heat transfer from the heated platen to the coated platen and the food product being cooked. Following cooking of the food product, the upper platen is raised, and the food product remains on the lower grill surface because the coating of the upper surface prevents the product from sticking to the non-stick coating over the heated platen.

Abstract: The detector is a watertight unit that is easily secured on or through a vehicle bumper, or other extremity, to sense and give warning of obstacles in the path of the vehicle. Warning is given by either head on or oblique contact of a detector probe with the interference. Advance time of such warning may be altered by changing the length of the probe. The detector contains an electrical switch, closed by probe displacement, to activate the available vehicle horn. Utilizing independently powered equipment provides the warning quickly and without the need of significant and/or prolonged relative motion between the vehicle and the obstacle. The invention is readily adaptable for use on fixed objects to provide warning of vehicle approach.