Sawtek, Inc.

Other

Jorgen W Andersen

A sensing apparatus includes a sensor package for generating an output signal responsive to a sensed quantity. The sensor package includes a surface acoustic wave (SAW) sensor and driver driver circuit mounted within a common package to facilitate connection to the associated processing apparatus. More particularly, the SAW sensor has a delay related to a sensed quantity, but generates undesirable reflections responsive to pulses propagating therethrough. The driver is controllable for delivering a series of pulses to the SAW sensor with each pulse having a random phase to thereby reduce effects of the undesired reflections of the SAW sensor. The sensor package also preferably includes connectors carried by the package for facilitating connection of the sensor package to the associated processing apparatus to permit susbstitution or replacement, for example.

Time domain delay device measurement apparatus including sensor package

A sensing apparatus includes a pulse recirculating circuit operatively connected to at least one ultrasonic delay sensor or other device for recirculating pulses therethrough, and a measurement difference output circuit for generating an output signal based upon a difference between first and second measurements of the at least one ultrasonic delay sensor. The pulse recirculating circuit preferably comprises a pulse generator for generating a series of input pulses to the ultrasonic delay sensor, and a pulse detector for detecting a series of output pulses after propagation through the ultrasonic delay sensor. Moreover, the measurement difference output circuit preferably includes an up-down counter for counting pulses during the first measurement in one direction and for counting pulses during the second measurement in an opposite direction. Accordingly, the remaining counter contents represent a difference in delay between the first and second measurements. Method aspects of the invention are also disclosed.

Apparatus and associated method for measuring differences in delay

An embodiment of a sensing apparatus includes an ultrasonic delay sensor having a delay related to the sensed quantity; and a time domain analysis circuit for recirculating pulses through the ultrasonic delay sensor or device and for generating the output signal related to the sensed quantity. In particular, the time domain analysis circuit may include a pulse generator for generating a series of input pulses to the ultrasonic delay sensor; a pulse detector for detecting a series of output pulses after propagation through the ultrasonic delay sensor; and a pulse recirculating circuit for causing the pulse generator to generate the series of input pulses based upon respective previously detected output pulses from the pulse detector. The apparatus also preferably includes circuits for suppressing the undesirable reflections generated by the ultrasonic delay sensor. For example, random phase switching may be used for randomly switching phases of the series of input pulses to the ultrasonic delay sensor to thereby reduce undesired reflections. In addition, a fixed delay may be operatively connected between the pulse detector and the pulse generator. Also time diversity matching to the ultrasonic delay device may also be used to suppress the effects of undesired reflections. Method aspects of the invention are also disclosed.

Time domain delay measurement apparatus and associated method

An apparatus includes an ultrasonic delay sensor or device having a delay related to the sensed quantity; a pulse recirculating circuit for recirculating pulses through the ultrasonic delay sensor for generating a pulse repetition signal having a frequency related to delay of the ultrasonic delay sensor; and an output circuit for generating an output signal related to delay in the ultrasonic delay sensor based upon a difference in phase velocity between the pulse repetition signal and a time base signal. The output circuit preferably includes a first multiplier for multiplying the pulse repetition signal by a first number, and a second multiplier for multiplying the time base signal by a second number to have a frequency substantially the same as the multiplied pulse repetition signal. The effects of undesired reflections in the ultrasonic delay device may also be reduced or suppressed. Method aspects of the invention are also disclosed.

Differential phase velocity determining delay measurement apparatus and

A coupled resonator filter oscillator having an impedance matching network coupled between an amplifier and a filter. The impedance value of the amplifier varies due to amplifier gain compression. The network maintains a constant impedance to the filter when said amplifier's impedance changes to preserve the filter's original transfer function.

Oscillator circuit employing quadrature networks for maintaining a

A D.C. motor speed control uses the motor as both the prime mover and feedback element. The motor back e.m.f. is sampled periodically to generate a feedback signal which is not dependent on motor characteristics for the control loop dynamic response. An adaptive positive feedback control loop is employed.

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Orlando, FL, United States of America

Jorgen W Andersen