Abstract: A resonator produces a signal which is processed by being digitized and demodulated. The processed signal is applied to a filter having three sections. The first is a lowpass filter, the second is a decimator, and the third is an equalizer filter. The lowpass filter filters out the high frequency components which would be aliased by the decimator. The equalizer filter performs whatever processing as is appropriate for the measurement which is sought. A second or subsequent equalizer filter may be driven by the first. The lowpass filter and the equalizer filters all have the same architecture of allpass filters, weighting elements, and adders. The weights applied to the weighting elements vary to perform the varied purposes of the various filters. The filtered signal is applied to a display, such as a human operator, or a device (such as an auto-pilot) either in or out of a feedback loop, or both.

Abstract: An alerting process is presented that uses the steps of first receiving at least a first signal from a signal source for a predetermined short interval. The first signal is analyzed over the predetermined short interval to obtain the spectral energy of the first signal within contiguous incremental frequency bands that extend over the frequency spectrum of interest. The energy value obtained for each incremental frequency band is then stored as a short term integrated value in a memory at an address location corresponding to the incremental frequency. Successive short term integrated values are then integrated over a predetermined long term interval to obtain a long term integrated value for each respective incremental frequency band. Each short term integrated value is then divided by the corresponding long term integrated value to obtain an enhanced STI frequency value for each incremental frequency band.

Abstract: Information often modulates an underlying carrier signal, thereby producing a modulated information signal 70. This same carrier signal is required, with a few modifications, to demodulate the modulated information signal. This required signal is called the demodulator reference signal. It must be complex, that is, it must contain separate in-phase and quadrature outputs. A degraded version 10 of this signal is often available with the correct frequency, but with the wrong phase and amplitude, and with a direct current (dc) offset. The present invention 68 produces a digital demodulator reference signal 38, 46 from the degraded signal 10. It eliminates dc offset with a dc blocker 18, adjusts amplitude with a scaler 14, adjusts phase with a first Hilbert transformer 20, multipliers 26 and 28 and summer 34, and produces in-phase and quadrature outputs with a second Hilbert transformer 36 cascaded with the first.

Abstract: This detector provides a computationally simple digital low power detector of symbol rate, also called baud rate. It uses an approximate Hilbert transform function to create approximate in-phase and quadrature signals. An approximate envelope detector (feature extractor) processes these signals to produce a signal with a strong frequency component at the symbol rate. This signal is then filtered, accumulated, and threshold detected. The approximate in-phase and quadrature signals are formed by a linear sequence of six delay elements, the output of the third delay element being the in-phase signal. A first summer receives the output of the second delay element at a minus input and the output of the fourth delay element at a plus input. A second summer receives the signal input at a minus input and the output of the sixth delay element at a plus input, and drives a right two bit shifter.

Abstract: A digitally driven, analog bandpass filter has an analog summer and two analog delay elements connected in a loop. An input signal to the filter is applied to a plus input terminal of the summer, and the output of the second delay elements is applied to a minus input terminal of the summer. The output of filter may be taken either from the output of the summer, or from the output of the second delay element, or from any point in between. Each delay element is driven by a two phase non-overlapping clock, and each element passes a charge from a first capacitor through an op amp to either a second capacitor (first phase) or a third capacitor (second phase). Amplification may be provided by adjusting the ratio of the second (or third) capacitor to the first capacitor. If a differential op amp is used, both sides of the op amp are clocked together, and each side has its own trio of capacitors identical to the trio on the other side.

Abstract: A spatial power combiner includes a circularly corrugated horn 26, a meniscus lens 28, an amplifier array 16, and a layer of microwave absorbing material 34 on a housing interior 32. The lens 28 receives polarized microwave radiation from the horn 26 and collimates it, renders it in phase and with nearly uniformly amplitude, and distributes it across the lens aperture. The amplifier array 16 amplifies the radiation and re-radiates it, orthogonally polarized, to the lens 28, which focuses it back down the horn 26. An array of parasitic micropatches 24 between the lens 28 and amplifier array 16 provides impedance matching. A quarter-wave anti-reflecting coating 30 covers both surfaces of the lens 28. The microwave absorbing material 34 reduces or prevents resonance of higher order modes.

Abstract: A gyroscope includes one or more drive cylinders operatively attached to a pickoff member, which can be in the form of a disk or cylinder. Where the pickoff member is cylindrical, the gyroscope is configured as three axially-aligned cylindrical members attached end to end, the outer two functioning as drive cylinders and the inner one functioning as a pickoff cylinder. The drive cylinders have a single electrode on the outside diameter and a single electrode on the inside diameter. The pickoff cylinder has a single electrode on the outside diameter and a plurality of electrodes on the inside diameter. In the preferred embodiment, the three cylindrical members are integrally formed with one another from piezoelectric material that is polarized radially, and each drive cylinder is attached to the pickoff cylinder by a plurality of connecting members or posts located at the separations between the pickoff electrodes. The posts are preferably staggered positionally as between the two drive cylinders.

Abstract: A tracking filter has a tunable filter responsive to an input signal for producing a filtered output signal, a Hilbert transformer for producing an in-phase reference signal and a quadrature-phase reference signal from the filtered output signal, and a discriminator responsive to the input signal and the in-phase and quadrature-phase reference signals for producing a passband center frequency control signal and a passband width control signal for controlling the passband center frequency and the passband width of the tunable filter. The frequency discriminator performs complex demodulation of the input signal with the in-phase reference signals to produce respective in-phase and quadrature-phase baseband signals which are low-pass filtered. The quadrature-phase baseband signal is divided by the in-phase baseband signal. The quotient is integrated to produce the passband center frequency control signal.

Abstract: A dual in-line package 12 for an integrated circuit 10 has pins 14 which engage the holes of a complementary socket 16, having two rows 16a and 16b. A portion of one row 16b is omitted, allowing the holes 22 of a cable connector 24 to engage the corresponding pins 20 of the package 12.

Abstract: A drive circuit provides approximately zero phase shift across the terminals of a resonator, and provides a constant excitation of the resonator, while cancelling variation due to the shunt capacitance. For complex demodulation of an angular rate signal from a vibrating quartz angular rate sensor, the drive circuit also provides an in-phase reference signal and a quadrature-phase reference signal. Preferably, the drive circuit includes an adjustable phase shifter connected in a feedback loop including the resonator for adjusting a phase shift of a periodic signal circulating in the feedback loop, and the adjustable phase shifter includes a Hilbert transformer for producing an in-phase signal and a quadrature-phase signal, and a combiner circuit connected to the Hilbert transformer for combining a selected amount of the quadrature signal with the in-phase signal to produce a result shifted by a selected amount of phase.

Abstract: The LOW POWER CRYSTAL OSCILLATOR shown here reduces power consumption of a Pierce oscillator which has an inverter preferably made of an NFET N0 and a PFET P0 in series. A load, preferably an NFET N1 with its gate wired to its source, is placed in parallel with a switch, preferably a PFET P1, between P0 and Vcc. A clamp, preferably a PFET P2 with its gate wired to its source, is placed in parallel with a switch, preferably an NFET N2, between N0 and ground. The switches are enabled during power-up, thereby providing quick turn-on of the oscillator. They are then disabled, thereby reducing the voltage across the crystal XTAL and consequently reducing the power consumed.

Abstract: A millimeter wave radar is placed on an aircraft and several radar targets are placed near a runway. The targets are discrete objects, each having a relatively localized radar cross section, a unique signature or a unique range bin, and a position which is accurately known. Targets should be spread over the length of the runway. Radar corner reflectors and active or passive repeaters are preferred. The locations of the radar targets with respect to the runway can be transmitted to the aircraft, or they can be stored on board. On board memory requirements can be reduced by requiring all airports to select one of only a few standard target placement patterns, or even only one. Targets are inexpensive, as are radars whose only precision requirement is in range, and not in azimuth or elevation angles. Range to at least three targets in the radar's field of view is all that is required for an on-board computer to determine the aircraft's location.

Abstract: An opto-coupling device lies between an analog input circuit, such as a telephone line, and a processing apparatus, such as a modem. The device has a high impedance circuit; this is, its impedance is high with respect to the input impedance of the analog input circuit. This high impedance circuit has a voltage/current conversion circuit. The variations of the current flowing through the conversion circuit are directly induced by the variations in the voltage of the analog input signal. The high impedance circuit is in series with a constant current source, and is connected to the analog input circuit. The inputs of the opto-coupling device are in parallel with the voltage/current conversion circuit.

Abstract: A bi-directional spatial power combiner grid amplifier has an array of parasitic elements between the lens and the amplifier. The elements have different impedances to radiation of a first polarization (incident radiation) and of a second polarization which is orthogonal to the first (amplified radiation), thereby providing impedance matching to both the input and the output of the grid amplifier. The elements preferably are separated slots or dipoles (some in each direction of polarization), crossed slots or dipoles, or micropatches.

Abstract: The signal processor including a CPU 10 which selects a context register 16, the contents of which configure an address generator 20 and a data type converter 22. A narrow parameter from the CPU 10 produces a broad address for the generator 20 to pass to the memory 28. The converter 22 converts data between memory 28 format and CPU 10 format. A different context register 16 may be selected by each code line of software. The generator 20 preferably calculates a data element length which is the product of an odd number and a power of two, each number being specified in the content of the Context Register 16. Elements are clustered into groups, one group for each element length, and the groups are arranged in order of ascending element length. The index identifying the individual element of a group with a larger element length does not begin with zero (or one).

Abstract: The BRANCH DECISION ENCODING SCHEME shown herein overcomes the limitations of a dedicated debug port on a single chip computer processor. A dedicated debug port resolves many of the problems associated with an add-on logic analyzer, except for its limitation of an eight bit data interface. The 8 bit port is required as a trade-off between the device I/O requirements and development tools. During real time program development, it is virtually impossible to monitor the 24 bit program counter through a port only a third as wide. The present invention solves this problem by taking advantage of the sequential characteristics of application programs. There is a discontinuity in the program counter in only a limited number of situations: branches, jumps, subroutine calls and returns from subroutines, exceptions and returns from exceptions, traps and return from traps, and loopbacks to the tops of loops.

Abstract: The amplitude or frequency of a sinusoidal signal represented as sample values S.sub.1, S.sub.2, S.sub.3, S.sub.4 is estimated by computing a triplet of differences x.sub.1, x.sub.2, x.sub.3, where x.sub.1 is a difference between S.sub.2 and S.sub.1, x.sub.2 is a difference between S.sub.3 and S.sub.2, and x.sub.3 is a difference between S.sub.4 and S.sub.3. An indication of the estimate of the amplitude or frequency is computed as a ratio of algebraic functions of the differences x.sub.1, x.sub.2, x.sub.3. The amplitude is computed as the square root of a first ratio of algebraic functions, and the frequency is computed as an arc-cosine function of a second ratio of algebraic functions. Preferably the ratio is evaluated by a division operation computed as a polynomial approximation, and the square root function and the arc-cosine function are also computed as a polynomial approximation. Preferably ratios computed from a plurality of triplets are averaged together to give more accurate estimates.

Abstract: A single-precision multiplier used in a recursive digital filter is rendered more precise, without resorting to extended-precision or floating-point arithmetic. A double-precision multiplier produces a group of most significant bits (MSBs) and a group of least significant bits (LSBs). The LSBs are processed, including delaying them by one or two clock cycles, and are then added back to the LSBs produced during the present clock cycle. The top few bits of this first sum are right shifted as far as possible and added to the MSBs, the resulting second sum being the output of the overall multiplier.

Abstract: A modem is tested using HP3065 with AT commands. The modem is tested as a whole, thereby assuring that the correct components are being used and that they will work with one another.

Abstract: To demodulate an analog signal having information modulated by a carrier, the analog signal is chopped by a chopper, the chopped signal is digitized by a sigma-delta analog-to-digital converter to produce a series of digital samples at a sampling frequency, the digital samples are filtered in a digital decimating filter to produce data words, and the data words are modulated by an intermediate frequency signal to produce a detected information signal. The various frequency signals are generated by a phase-lock loop so that the intermediate frequency is the difference between the carrier frequency and the chopping frequency, and both the chopping frequency and the intermediate frequency are sub-multiples of the sampling frequency.