Fluke Corporation

Hewlett-packard Company

The Spectranetics Corporation

Thomas K Bohley

James Anthony Kahkoska

Christopher Koerner

Grosvenor H Garnett

Charles E Moore

Thomas Doumas

Mark D Keisling

Ronald C Westlund

Laura Whiteside

Allan I Best

James A Kahkoska

A digital toner/locator employs tone packets using a 455 Khz carrier. Plural packet quanta provide multiple test modes which are advantageously selected from a probe without requiring returning to the tone generator to change mode.

Locating a cable using synchronization portion and data portion of a tone packet of a system

A digital toner/locator employs tone packets using a 455 Khz. carrier. Plural packet quanta provide multiple test modes which are advantageously selected from a probe without requiring returning to the tone generator to change mode. A locate and isolate mode are provided, as well as multiple song selection, for choice of alternative songs played by the detector when the tone packets are detected.

Digital cable toning apparatus and method

A time domain reflectometer having a first impedance when in a first test mode and a second impedance when in a second test mode. The first impedance is substantially the same as the nominal characteristic impedance of a network link cable not connected to a network and the second impedance is substantially different from the impedance of a network link cable that is terminated into a network. A method for measuring the length of a terminated network cable includes the steps of determining that the network cable is terminated at a network, selecting a test mode suitable for testing the terminated network cable, and performing time domain reflectometry testing on the terminated network cable.

Time-domain reflectometer for testing terminated network cable

A test device for assisting in locating a cable efficiently provides both tone and link pulses simultaneously to a cable under test. The link pulses are alternated between transmit and receive pairs on the cable.

Method of and apparatus for simultaneously providing tone and intermittent link onto a cable to assist identifying the cable

A hand held test instrument measures cable lengths by applying a square wave signal to a conductor of a pair and detects the induced current in the other conductor of the pair. A synchronous detector measures the induced current, which is representative of the capacitance of the cable, which is representative of the length of the cable.

Capacitance measuring technique for estimating cable length

A laser catheter contains groups of optical fibers, each group forming a spiral pattern or radially straight lines, extending from near the inner wall of the laser catheter to the outer wall. The laser catheter is rotated about its longitudinal axis to ablate a target.

Optical fiber catheter with spaced optical fiber

A plural channel indirect digital to analog converter. Words containing address bits and data bits are received on an input and entered into a specific one of the converter channels under control of the address bits of the word. The data bits are applied to a binary rate multiplier of the channel which generates a pulse modulated output signal representing the binary value of the received data bits. The pulse modulated output signal is applied to an associated filter which converts the pulse modulated signal to an analog output signal whose amplitude represents the binary value of the received data bits. Gating circuitry ensures that each output pulse is of a precisely controlled pulse width. One of the converter channels is used to calibrate the output level of the filters. The number of data bits applied to the different channels may need not be the same and may vary in number from a minimum of 1 to a maximum of m.

Indirect D/A converter

Pulse modulation circuitry which receives n binary data bits and generates a rate/width pulse modulated signal representing the binary value of the received data bits. The lower order m of the n bits generate a rate modulated signal having a number of pulses equal to the binary value of the m bits. The remainder of the n bits width modulate the rate modulated pulses. Each least significant bit increase in the binary value of the received date bits increases the width of a rate modulated pulse by a predetermined amount.

Combined rate/width modulation arrangement

Methods and apparatus for random repetitive sampling in digital oscilloscopes is disclosed using a psuedo-random noise generator to vary randomly the beginning of a search for a trigger event to enable the acquiring of data which has no gaps.

Apparatus for random repetitive sampling

A triggerable oscilloscope having a digital clock selectably connected to two digital counters accurately measures a time interval between two recurring events. The first digital counter is connected to the digital clock to count clock pulses during a timer interval between the initiation of a horizontal sweep signal and the occurrence of the first recurring event. A second digital counter is connected to the digital clock to count clock pulses during a time interval between the initiation of a sequent horizontal sweep signal and the occurrence of the second recurring event. A subtractor circuit coupled to the first and second digital counters subtracts the count of the first digital counter from the count of the second digital counter and determines the time interval between the first and second recurring events. Time averaging techniques increase the accuracy of the time interval measurements for high speed recurring events by accumulating counts during a plurality of horizontal sweep signals. Predivide techniques are used for low speed recurring events to limit the number of counts accumulated during a horizontal sweep signal to a number compatible with the capacity of the digital counters.

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Colorado Springs, CO, United States of America

Thomas K Bohley