Other

Hewlett-packard Company

Keysight Technologies, Inc.

Robert W Leiby

Bryan D Boswell

Alan J Baker

Steven Joseph Narciso

A dynamic switch contact protection circuit and technique to protect a channel switch within an electrical system by limiting transients when the switch is turned on or turned off. The protection circuit comprises switching between a high resistance path and a low resistance path. The high resistance path comprises a resistor. A bypass switch is connected in parallel to the resistor to affect the low resistance path. The protection circuit can connect or disconnect switch cards to the electrical system enabling the creation of a larger switching structure. Disconnected switch cards within a switching structure preserves system bandwidth by limiting capacitive loading. Electing which switch to close last or open first can prolong the length of usage of the switches.

Dynamic switch contact protection

An inverting amplifier having variable gain in M discrete steps that are a fixed ratio F apart may be constructed by grounding the non-inverting input of a high gain differential gain element, and connecting the inverting input through a single-pole M-throw switch to the N.sup.th terminal in a ladder network of M cascaded elements. Each element is a series R and X, with X grounded, and their junction being where the next element of the ladder is connected. These junctions are also the aforementioned terminals of the ladder network, and are what are coupled to the M throws of the switch. At an input end of the ladder network is another impedance Z, to which the input V.sub.in is applied. At the other end of the ladder network is a final R in series with another Z that is driven by the V.sub.out obtained from the output of the gain element. Once Z and F are selected R and X may be found according to the relationships R=Z[.sqroot.(1/F)-1]and X=Z[.sqroot.(1/F)]/[.sqroot.(1/F)-1]. FET's may used to provide a make before break switch. The setting of the switch picks N, which determines the variable gain.

Discrete step variable gain inverting amplifier with constant ratio

A phase measurement between two signals is performed by beginning on an arbitrary zero crossing of the signal from the reference stator and forming, for each rotor, the sum of the times for the zero crossings for one complete revolution. To avoid the effects of crosstalk the rotors may have different numbers of poles. The sums, the different numbers of poles, the time for one revolution, and, for each rotor, the number of poles from the pole corresponding to the first term in the associated sum to an absolute reference pole, are the variables in a phase formula producing a high accuracy and resolution unified answer free of separate coarse and fine components. The absolute reference poles may be missing poles whose absence is detected and replaced with an estimate.

Method and apparatus for reducing crosstalk effects upon phase

An angle transducer includes input rotor and reference rotor assemblies that are mounted for rotation upon a common shaft and that cooperate with respective moveable input stator and fixed reference stator assemblies to produce signals whose phase difference represents an input angle. Diametrically opposed sensors in each stator assembly achieve enhanced eccentricity error reduction by producing separate signals whose phases are averaged after the phase of each is individually measured. A phase measurement technique does not rely upon the mechanical accuracy of the angular placement of the poles for the rotor assemblies. A phase measurement between two signals is performed by beginning on an arbitrary zero crossing of the signal from the reference stator and forming, for each rotor, the sum of the times for the zero crossings for one complete revolution. To avoid the effects of crosstalk the rotors may have different numbers of poles. The sums, the different numbers of poles, the time for one revolution, and, for each rotor, the number of poles from the pole corresponding to the first term in the associated sum to an absolute reference pole, are the variables in a phase formula producing a high accuracy and resolution unified answer free of separate coarse and fine components. The absolute reference poles may be missing poles whose absense is detected and replaced with an estimate. State and time of transition data for one revolution's worth of all of the signals from the stators are temporarily captured in a small high speed revolving buffer and then immediately stored in a larger wrap-around memory under the control of an interrupt system of a microprocessor. To perform an angle measurement the microprocessor analyzes the last complete revolution's worth of data, beginning at any point in the revolution.

An angle transducer includes input rotor and reference rotor assemblies that are mounted for rotation upon a common shaft and that cooperate with respective moveable input stator and fixed reference stator assemblies to produce signals whose phase difference represents an input angle. Diametrically opposed sensors in each stator assembly achieve enhanced eccentricity error reduction by producing separate signals whose phases are averaged after the phase of each is individually measured. A phase measurement technique does not rely upon the mechanical accuracy of the angular placement of the poles for the rotor assemblies. A phase measurement between two signals is performed by beginning on an arbitrary zero crossing of the signal from the reference stator and forming, for each rotor, the sum of the times for the zero crossings for one complete revolution. To avoid the effects of crosstalk the rotors may have different numbers of poles. The sums, the different numbers of poles, the time for one revolution, and, for each rotor, the number of poles from the pole corresponding to the first term in the associated sum to an absolute reference pole, are the variables in a phase formula producing a high accuracy and resolution unified answer free of separate coarse and fine components.

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Fort Collins, CO, United States of America

Robert W Leiby