Trimble Navigation Limited

Ford Aerospace & Communications Corporation

Other

Raychem Limited

Loral Aerospace Corp.

Clover Network, Inc.

Integrated Device Technology, Inc.

Ses-imagotag Gmbh

Gary L Wagner

Chung Y Lau

Eric B Rodal

Gerald L Shimirak

Nelson M Shen

Reed A Parker

Michael J Serrone

Philip B Vail

Alvin Alza Dominguez

Arvind Antonio De Menezes Pereira

Nils Wydler

Mel Nance

Louis John Dietz

Anthony Vranicar

Alexandru S Gliga

Mohamed Hussein Higgy

Julius Lange

Geoffrey S Waugh

Michael E Jacobson

Daniel Linebarger

Timothy P Halloran

Various methods and devices that involve tuning filters are disclosed. A disclosed method for tuning a filter comprises trimming a center frequency of the filter. The method also comprises trimming an input signal magnitude of the filter. The method also comprises measuring a performance metric of the filter after trimming the center frequency of the filter and the input signal magnitude of the filter. The method also comprises repeating the trimming steps and the measuring step until the filter is tuned for a first physical test condition. A disclosed device that includes a filter also includes first and second trimming circuits that trim the center frequency and input signal magnitude of the filter. A disclosed system includes a motor to transfer a transmitting device from a first physical test condition to a second physical test condition relative to a proximity coupling device with a filter.

System and method for automatic filter tuning

Integrated circuit oscillators include a cascaded arrangement of first and second all-pass networks containing a resonator therein, such as a crystal-based resonator. The second all-pass network is configured to provide negative feedback to the first all-pass network at DC (i.e., very low frequencies) and is further configured to provide positive feedback with 90 degrees of phase to the first all-pass network at the resonant frequency of the resonator, which may be the third overtone frequency of a crystal resonator. The first all-pass network includes the resonator and the second all-pass network includes a resistor having resistance matched to a motional resistance of the resonator at the resonant frequency.

Third overtone crystal-based oscillators having tunable all-pass RC filters therein

A GPS receiver and an RF GPS integrated circuit for receiving a GPS signal. The GPS integrated circuit includes a synthesizer for generating LO signals, first and second downconverters for using the LO signals for downconverting the GPS signal, and a sampler for providing in-phase and quadrature phase sampled output signals representative of the GPS signal. The synthesizer includes a multi-mode divider for providing substantially the same first LO frequency at about the midpoint of the L and L GPS lo frequencies for either of two reference frequencies. The RF GPS integrated circuit uses an entirely on-chip voltage controlled oscillator (VCO) having a resonator for generating the LO signals and an entirely on-chip filter for filtering a first intermediate frequency signal.

RF integrated circuit for downconverting a GPS signal

A jamming signal cancellation method and apparatus for removing an undesired in-band CW jamming signal from a desired spread spectrum signal. The jamming cancellation apparatus includes a limiter, a summer, and a feedback loop. The feedback loop includes the summer, a harmonic filter, a mixer, a loop/filter amplifier, and an adjustable gain control (AGC). The limiter limits the waveform of the input signal and issues a limited signal to the AGC and the mixer. The AGC controls the amplitude of the limited signal and passes a controlled amplitude signal to the summer. The summer takes a difference between the input signal and the controlled amplitude signal and passes a difference signal to the filter. The filter filters the harmonics that were created by the limiter and passes an output signal to the mixer. The mixer multiplies the filtered signal by the limited signal to provide an error signal that is proportional to the amplitude of the fundamental frequency in the difference signal. The error signal is then passed through the loop/filter amplifier and used in the AGC to drive the amplitude of the controlled amplitude signal to equal the amplitude of the waveform of the input signal, effectively eliminating the CW jamming signal from the output signal, and thereby improving the signal-to-jamming ratio of the output signal with respect to the input signal.

Apparatus and method for improving signal-to-jamming ratio in a spread

A method of forming a tap into an intermediate point on a continuous coaxial cable, and a coaxial cable tap housing suitable for forming such a tap. The tap housing includes a recess and an alignment element having a predetermined spatial relationship with the recess. The recess has an entry, an exit and a passage connecting the entry and exit. When the tap housing is fixed to a cable, the exit of the recess is closer to the outer conductor of the cable than the entry of the recess is to the outer conductor. The alignment element is used to position a cutting tool which is inserted through the entry of the recess to form an opening in the outer conductor and a cavity in the dielectric under the opening. A tap insert, which includes a coupler assembly, is mounted to the housing, and the coupler assembly is inserted through the entry of the recess and through the opening into the cavity formed in the cable. In specific embodiments, the recess and opening are elongated.

Coaxial cable tap with slitted housing and non-piercing tap insert

A frequency synthesizer comprises a voltage controlled oscillator (VCO) with an output frequency f.sub.out that is dependent on a VCO-control voltage input. A divide-by-k counter is connected to receive the output frequency f.sub.out and to output a pair of in-phase and quadrature phase signals f.sub.k. A vector modulator is connected to receive the in-phase and quadrature phase signals f.sub.k and the output frequency f.sub.out, and outputs a single sideband (SSB) modulated output f.sub.n comprising only one of the sum (f.sub.out +f.sub.k) or difference (f.sub.out -f.sub.k) products. A divide-by-n counter is connected to receive the modulated output f.sub.n and to output a feedback frequency sample f.sub.f. And a phase detector is connected to receive the feedback frequency sample f.sub.f and to compare it with a reference frequency f.sub.r. A phase error output signal is provided for the VCO-control voltage input.

Wide-range fine-step vector modulator frequency synthesizer

An inexpensive coaxial cable connector, and an inexpensive contact which is suitable for use in an such an inexpensive coaxial cable connector, the connector and the contact being capable of passing electrical signals from low frequency power up to and including telecommunications signals in the range of 1 GHz or more. The connector comprises an elongate, hollow, conductive, cylindrical barrel having an inner radius, R.sub.BARREL, and a first longitudinal axis; and an elongate, conductive contact. The contact has a first end and a second end which define a length therebetween, a second longitudinal axis, and comprises a cylindrical section. The cylindrical section has an outer radius, R.sub.CONTACT, which is less than R.sub.BARREL. The cylindrical section comprises a first external end which is coincident with one of the first end and the second end of the contact, a hollow interior, a first longitudinal slot, the slot located near the external end of the cylindrical section, and has a proximal end and a distal end. The contact also comprises a first spring-tab which is located within the first longitudinal slot and formed from a cut-out which forms the first longitudinal slot. The spring-tab has a fixed end and a free end, the fixed end joined at the proximal end of the slot. The first spring-tab extends generally from the proximal end of the slot toward the distal end of the slot and into the hollow interior of the cylindrical section. The connector comprises means for supporting the contact in the barrel so that the cylindrical section of the contact is contained within and spaced apart from the barrel and the second longitudinal axis is substantially coincident with the first longitudinal axis. The supporting means comprises a dielectric material.

Coaxial cable connector

A GPS receiver downconverter combines on a single integrated circuit, a first super-heterodyne mixer, a voltage controlled oscillator, a phase locked loop, a pair of quadrature mixers and a pair of quantizers with in-phase and quadrature-phase sampler outputs operable at twenty-five MHz and 2.5 MHz. Emitter-coupled logic and special low-voltage bipolar semiconductor technology are combined for 3.3 volt operation at under one hundred milliwatts.

Ultra low-power integrated circuit for pseudo-baseband down-conversion

A system for processing inphase and quadrature data channels, such as a Costas loop QPSK demodulator, employs an additional feedback loop for adjustment of phase offset between carrier reference signals, this loop being in addition to the Costas error loop for control of frequency and phase of an oscillator which provides the regenerated carrier signal. The additional loop employs cross-channel products of demodulated inphase and quadrature data signals as does the Costas loop. The regenerated carrier is applied via an adjustable phase-offset unit to provide quadrature carrier reference signals to phase detectors of inphase and quadrature data channels. The phase offset unit includes a 90 degree hybrid circuit energized by the carrier signal at a main input port plus an adjustable fraction of the carrier power applied to an auxiliary input port. Adjustment of the relative magnitudes of the signals at the two input ports of the hybrid circuit in accordance with the sum of the cross-channel products provides a desired amount of phase offset between the two carrier reference signals in correspondence with the deviation from orthogonality of the components of the composite input signal. This removes crosstalk resulting from the deviation in orthogonality of the components of the composite input signal.

Quadrature compensation for orthogonal signal channels

An embodiment of the present invention combines, on a single integrated circuit, a first bipolar transistor in a common-emitter configuration capacitively coupled to a second bipolar transistor in a common-base configuration, together with a capacitive input coupling for a single-ended input and directly-coupled collector outputs for a differential-output for driving successive differential-input and differential-output emitter-coupled transistor pairs for multiple stages of amplifier gain.

AC-coupled single-ended or differential-input radio frequency amplifier

An embodiment of the present invention is a single-chip GPS receiver front-end comprising a radio frequency amplifier, a voltage-controlled oscillator operating at a first local oscillator frequency, a divide by seven and one-half counter for deriving a second local oscillator frequency from the first and a first and second mixer. The local oscillator frequency is mid-way between two carrier frequencies of interest that may be received by the radio frequency amplifier and the first mixer produces a first intermediate frequency. The second local oscillator frequency is then beat with the first intermediate frequency in the second mixer to produce a second intermediate frequency. A dual-conversion super heterodyne configuration is therefore employed in which the first and second local oscillator frequencies are derived from a single oscillator and the first local oscillator frequency is seven and one-half times the second local oscillator frequency.

Integrated phase locked loop local oscillator

An embodiment of the present invention is a voltage controlled oscillator (VCO) comprised of a differential pair of transistors that have respective positive feedback paths with phase-lead networks cross-coupled. Each positive feedback path on each side has two different phase-lead branches. The two phase-lead branches have the same phase differences on each side of the differential pair, in order to maintain a symmetry that improves common-mode noise rejection on a voltage control differential input. Current-steering is used to control the mixture of currents that arrive at the bases of the differential transistor pair from the respective two different phase-lead branches, and thereby changing the frequency of the VCO.

Voltage controlled oscillator suitable for complete implementation

An electronic data filter system (10), which functions as an approximation of a perfect matched filter, receives a conventional square-wave digital input signal (12) and outputs a filtered output signal (18). Output signal (18) appears as the summed integral of input signal (12). Filter system (10) includes a rate detector (50), which receives input signal (12) and provides a tuning voltage (16), and a data filter (30) which provides output signal (18). Data filter (30) includes, arranged in series, a notch filter (80) and a low-pass filter (90), wherein such filters (80, 90) contain capacitive-inductive circuits having certain value ratios which are tunable responsive to tuning voltage (16). Signal degradation of the filtered signal (12, 18) is minimized by filter system (10), which reduces the bit error rate (BER) and noise bandwidth of the filtered signal (12, 18). In one embodiment, data filters (30) are cascaded in parallel to extend data filtering bandwidth.

Tunable data filter

A lock detector (12) used in conjunction with a bit synchronizer (14) for determining when a random binary input signal (2) is in lock with a clock (7) generated by the bit synchronizer (14). A window comparator (3, 5; or 23, 25, 27) determines whether the amplitude of the input signal (2) is within or without an amplitude window, and generates a signal (33) as a result of said determination. This signal (33) is sampled at periodic sampling points (X, Y). The set of X sampling points and set of Y sampling points are interleaved and usually separated by half a bit period. The X samples and Y samples are averaged and compared. Means (19) are provided for declaring a lock condition when the X average exceeds the Y average by a preselected threshold (V.sub.REF), which occurs when the X points are positioned near mid-points of data bits (35) and the Y points are positioned near data transitions (39). The circuit (12) will not lock on false sidebands and can operate at very low signal-to-noise ratios.

Growing community of inventors

Menlo Park, CA, United States of America

Gary L Wagner