Abstract: A system and method for extending the range of a base unit is disclosed. The system can include repeaters and/or network decoders, each of which is housed in a network module. The network module includes a first portion for insertion into a powered outlet. The first portion receives power from the powered outlet. The network module further includes a second portion for receiving a powered device, and an electronic housing that is coupled to the first and second portions. The electronic housing encloses an electronic unit for receiving power from the first portion and selectively providing power to the second portion. The electronic unit can also include a repeater for receiving commands and re-broadcasting the commands, and/or an active network device for receiving commands, decoding the commands, and controlling at least one device based on the command. The electronic unit can receive signals and transmit signals via a wired connection or a wireless link.

Abstract: A loudspeaker assembly includes a chassis, a magnet assembly supported by the chassis and disposed at a rear side thereof, a moveable voice coil, a rear suspension, and a diaphragm connected to the voice coil and to the chassis. The assembly defines a voice coil gap receiving the voice coil. To improve the cooling of the assembly, particularly when the magnet assembly includes neodymium, the assembly is positioned at least substantially in front of the diaphragm, and the chassis is positioned outwardly of the magnet assembly. Heat generated by the coil, which could adversely affect the magnet, is dissipated by conduction to the chassis and by convection and radiation to ambient air. The rear suspension supports the voice coil, is secured to the assembly and is connected to the chassis only through the magnet assembly and through the diaphragm.

Abstract: A method and apparatus for sensing audio frequency-pressure modulation of the moisture content of the atmosphere caused by a moisture-laden audio source, such as a live human voice, is disclosed. A first light emitter is provided to generate a first light beam. An audio source that emits moisture, and the environment, modulate the first light beam to generate a first modulated light beam. A first detector is provided to detect and demodulate the first modulated light beam to recover an uncompensated audio signal. A second light emitter is provided to generate a second light beam. The second light beam is modulated by the environment and not by the audio source to produce a second modulated light beam. A second detector is provided to detect and demodulate the second modulated light beam to recover the signal component caused by environmental conditions.

Abstract: A system and method for extending the range of a base unit is disclosed. The system can include repeaters and/or network decoders, each of which is housed in a network module. The network module includes a first portion for insertion into a powered outlet. The first portion receives power from the powered outlet. The network module further includes a second portion for receiving a powered device, and an electronic housing that is coupled to the first and second portions. The electronic housing encloses an electronic unit for receiving power from the first portion and selectively providing power to the second portion. The electronic unit can also include a repeater for receiving commands and re-broadcasting the commands, and/or an active network device for receiving commands, decoding the commands, and controlling at least one device based on the command. The electronic unit can receive signals and transmit signals via a wired connection or a wireless link.

Abstract: A solid-state gyroscope in a closed flight-control loop produces a DSSC QAM body angular-rate output signal and a drive current, which is converted to a demodulation reference signal. The frequency of the demodulation reference signal drifts slowly. A digital complex AM demodulator must demodulate the rate-output signal and correct the phase shift with as little delay as possible. This demodulator employs three elemental Hilbert transformers (EHT), one for direct current (d.c.) blocking and two for phase shifting. The gains of these Hilbert transformers shift with the drive frequency. In order to hold signal-path delays to a minimum, the gains of the Hilbert transformers are held to unity by means of a simple Least Mean Squared (LMS) adaptive loop whose output feeds the gain multiplier of all three Hilbert transformers. Automatic phase-shift correction is also included by adaptively rotating the demodulator reference phase in order to decorrelate the outputs of the demodulator.

Abstract: A controller that communicates with a first set of devices and a second set of devices is disclosed. The controller includes a transmitter for transmitting commands to remotely control the first set of devices, and for communicating input/output (I/O) data with the second set of devices. A microphone, speaker, display and cellular and cordless phone circuitry are integrated into the controller to provide the controller with phone and paging capabilities. Systems for determining the spatial location of a target object are also disclosed. The spatial location of the target object is determined with reference to a predetermined spatial reference point based on measured elapsed times, which represent the difference between a time reference and the time of receipt of a location signal from the target object at the known locations.

Abstract: A system for testing a microelectronic circuit includes a test bed for mounting a microelectronic circuit, and a signal source for applying a signal to a microelectronic circuit mounted on the test bed. The system additionally includes a test probe for wirelessly receiving electromagnetic response signals from the microelectronic circuit mounted on the test bed. In a preferred form, the electromagnetic response signals are radio-frequency signals. The test system additionally includes a computer connected to be test probe for analyzing the electromagnetic response signals. An integrated circuit for testing on the test system has a test circuit portion that emits electromagnetic radiation in response to a predetermined signal applied to the test circuit.

Abstract: A system for testing a microelectronic circuit includes a test bed for mounting a microelectronic circuit, and a signal source for applying a signal to a microelectronic circuit mounted on the test bed. The system additionally includes a test probe for wirelessly receiving electromagnetic response signals from the microelectronic circuit mounted on the test bed. In a preferred form, the electromagnetic response signals are radio-frequency signals. The test system additionally includes a computer connected to be test probe for analyzing the electromagnetic response signals. An integrated circuit for testing on the test system has a test circuit portion that emits electromagnetic radiation in response to a predetermined signal applied to the test circuit.

Abstract: A system and method for a directional microphone system is disclosed. The directional microphone system can adaptively track and detect sources of sound information, and can reduce background noise. A first monolithic detection unit for detecting sound information and performing local signal processing on the detected sound information is provided. In the detection unit, an integrated transducer is provided for receiving acoustic waves and for generating sound information representative of the waves. A processor is coupled to the transducer for receiving the sound information and for performing local digital signal processing on the sound information to generate locally processed sound information. A base unit is coupled to the first monolithic detection unit and includes a global processor which receives the locally processed sound information and performs global digital signal processing on the locally processed sound information to generate globally processed sound information.

Abstract: The described method and apparatus wirelessly test individual integrated circuit die on a wafer containing multiple die. The method incorporates activating a selected die on the wafer by wirelessly impacting the die with at least two beams of electromagnetic radiation so that the die receives radiation energy having at least a first energy level, thereby activating the die by causing a current to flow in the die. Each beam of electromagnetic energy individually has less than the first energy level required to activate the die. The beams of electromagnetic energy are directed so that they at least partially overlap on the selected die. In the region of overlap, the two beams together impact the die with an energy level at least equal to the first energy level required to activate the die. The method may additionally include detecting electromagnetic radiation emitted by the die in response to the electromagnetic energy received from the beams of electromagnetic energy.

Abstract: A method and apparatus for sensing audio frequency-pressure modulation of the moisture content of the atmosphere caused by a moisture-laden audio source, such as a live human voice, is disclosed. A first light emitter is provided to generate a first light beam. An audio source that emits moisture, and the environment, modulate the first light beam to generate a first modulated light beam. A first detector is provided to detect and demodulate the first modulated light beam to recover an uncompensated audio signal. A second light emitter is provided to generate a second light beam. The second light beam is modulated by the environment and not by the audio source to produce a second modulated light beam. A second detector is provided to detect and demodulate the second modulated light beam to recover the signal component caused by environmental conditions.

Abstract: A power source employs an environmental energy extractor. The environmental energy extractor operates to extract energy from the environment and provides the extracted energy either to power an electronic device, or to a storage device coupled to a battery charger for storing the extracted energy. The environmental energy extractor can include one or more energy modules. Each energy module is for extracting environmental energy and for providing the extracted energy to either the electronic device or the storage device. When more than one energy module is employed, the energy modules are configured such that the extracted energy provided by each module is summed, and the collective extracted energy of all the energy modules is provided to the electronic device or the storage device.

Abstract: Noise is removed from the digitized output of a sensor, subject to undesired resonance, even when the resonant frequency is unknown or drifts, with sufficiently low phase delay for the sensor to be used in closed-loop control. A very narrow notch filter which removes the resonance-induced noise is recursive (IIR) and therefore has a low phase delay. However, the apparatus which determines the center frequency of the notch filter is non-recursive, and therefore stable. It includes a tunable FIR filter which tracks the same resonance that we wish the IIR filter to remove. Tuning the FIR filter to minimize the output of the FIR filter therefore tunes the notch frequency to align with the resonant frequency. The tuning parameter which adaptively produces this result is suitably scaled and biased, and is applied to the IIR filter.

Abstract: An estimate of amplitude of a sinusoidal signal is computed from a value of the signal by computing the value of a quadrature-phase signal and computing the amplitude based on the value of the signal and the value of the quadrature-phase signal. The quadrature-phase signal is computed, for example, by a Hilbert transform. The amplitude is approximated as the sum of the magnitude of one value and an even polynomial of the other value when the magnitude of the other value is relatively small. The amplitude is computed precisely by an iterative application of the approximation. In an automatic gain control, for example, the desired value is substituted for the actual amplitude in the iterative formula, to compute an error estimate that always has the same sign as the actual error. Therefore, the automatic gain control converges to set the amplitude of the sinusoidal signal to the desired value.

Abstract: A first-order filter apparatus 48 (FIG. 4) includes an integrate-and-dump (I&D) circuit 50 and an output loop 52. The I&D circuit 50 is driven by a cyclic scaling element 54, which multiplies N consecutive input signals 56, x(m+1) to x(m+N), by a cycle of N scaling factors 58, c(1) to c(N). The I&D summer 60 drives a double-throw switch 62. The double-throw switch 62 applies the output of the I&D summer 60 to an I&D delay element 64 for N-1 input clock cycles, and for an Nth input clock cycle to the input of a non-cyclic scaling element 66. The non-cyclic scaling element 66 scales its input by a non-cyclic scaling factor, and applies its output to one input of a feedback summer 68. The output of the feedback summer 68 is y(k), the output of the apparatus. The index k advances by one every time that the index m advances by N. The output of the feedback summer 68 is also applied to an output feedback multiplying element 70, which multiplies it by B.sup.N.

Abstract: The in-phase channel 28 of a complex demodulated resonator data output signal 12 should contain all of the sensed information, and the quadrature-phase channel 32 should contain none of it. This will not happen if the phase of the reference signal 14 is incorrect. The phase may be adjusted by first filtering each demodulated channel with a respective low-pass dc-blocked filter 34, 38 which passes only the frequencies of the sensed information. If the sensed information gets through on both channels, then there will be a non-zero cross-correlation between the channels. This cross-correlation can be servoed to a minimum by use of a feedback signal 22. Doing so will cause all of the sensed information to be in one channel 28, and diagnostic information to be in the other channel 32.

Abstract: Noise may be reduced or eliminated from a digital sawtooth signal representing the phase of a periodic signal. This may be done precisely, even when inexpensive fixed-point arithmetic is used. In one aspect of the invention, the input signal (noise plus true signal) 12 is filtered to produce, in succession: (a) mod one differentiated noise plus slope of true phase signal 28; (b) mod one differentiated noise plus slope of residual phase signal (true phase signal minus estimated slope of true phase signal) 36; (c) mod one differentiated noise 46; (d) estimated noise 62; and (e) smoothed phase signal 72. In a second aspect, a noisy phase signal 12 is extracted from a first arbitrary periodic signal and the above steps are used to generate a noise-reduced phase signal 72. The noise-reduced phase signal 72 is then used to generate a second arbitrary periodic signal of the same frequency.

Abstract: A radar digital IF (intermediate-frequency) signal is to be complex demodulated, then processed through a two-channel real lowpass filter, prior to Doppler correction, clutter filtering, and other usual processing steps. A particularly efficient form of lowpass filtering for such applications is the so-called CIC (cascaded integrator/comb) filter. The first stage of such a filter is always an integrator. A conventional mechanization would therefore feature a conventional complex demodulator followed by an accumulator on each of the two demodulator outputs, followed by more processing. This invention more efficiently mechanizes this function by replacing the usual pair of multipliers and pair of accumulators (or integrators) with a single two-delay (54, 58) accumulator having an add/subtract control (48) on the input adder (42), and a pair of multiplexer switches (62, 66).

Abstract: Sparse sampling of an analog signal is desirable because it allows a large number of analog signals to be monitored using a minimum of electronics. The analog signals may be multiplexed and the multiplexed signal applied to a single analog-to-digital converter (ADC) driving a single digital processor. However, such sparse sampling undesirably lengthens the time it takes to get an accurate measurement of the signal. This delay is minimized by Hilbert transforming the digitized signal 16 to produce an in-phase signal I and a quadrature-phase signal Q, and by measuring I.sup.2 +Q.sup.2. I.sup.2 +Q.sup.2 is the square of the amplitude of the input signal. The input signal 12 is sampled at about four times the signal's frequency. DC bias is eliminated in a two-delay delay-subtracter dc blocker 18B. The de-blocked signal 20 is applied to a two-delay Hilbert transformer 22. Only five samples are required to accurately measure the amplitude of the input signal 12.

Abstract: For use with a quartz angular rate sensor, a frequency and phase-locked synthesizer recovers a reference signal virtually free of phase noise, and generates a quadrature-phase reference signal for complex demodulation of the angular rate signal. The synthesizer also ensures a precisely adjusted phase shift of approximately zero across the drive tines of the sensor. Moreover, the digital synthesizer provides a precise numerical indication of the drive frequency, which can be used for compensation and automatic tuning of filters, such as a tracking filter, a filter in an automatic gain control, and notch filters in the phase and/or frequency detectors in the digital synthesizer. The tracking filter is used as a pre-filter for the synthesizer, and is responsive to a passband-width control signal generated from the magnitude of the frequency and phase error signal controlling the frequency generated by the synthesizer.