Tektronix, Inc.

Tektronic, Inc.

Clifford E Baker

Daniel Bruce Meyer

Patrick A Quinn

Theodore G Nelson

Dale E Carlton

J Steve Lyford

John L Addis

John B Rettig

David T Rosette

Michael P Khaw

David H Olson

Ronald M Henricksen

Marvin E LaVoie

Philip K Jansen

Ray Zandonatti

A correction method for an electronic instrument accessory probe utilizes an error correction equation wherein at least one term contains an exponent less than unity. One simple such equation is: S&equals;Cs,&plus;Bs&plus;A&plus;b&verbar;s&verbar;,(where 0<x<1), but additional terms may be added, either with integer exponents greater than 2, or with other fractional exponents less than one. In the most simple embodiment, there are only four coefficients and the only term with a fractional exponent has an exponent of &frac12; (i.e., x&equals;0.5). A second set of coefficients may be needed for the correction of negative values.

Electronic measurement instrument probe accessory offset, gain, and linearity correction method

An electronic accessory assembly to be used with a host electronic instrument provides previously recorded data from a non-volatile memory as to the accessory's operational capabilities. This memory is accessed by a host device either when the host device is powered up, or when an new accessory is connected to the host device. The host device then uses this information along with the operational requirements of the user to set the operational parameters of the accessory/host combination to optimally perform the functions required by the user.

Accessory with internal adjustments controlled by host

An adapter suitable for use with a handheld multimeter and a thermocouple probe contains a temperature sensor and input connectors suitable for mating with standard thermocouple probes. Both of these are closely coupled thermally to an isothermal domain. Plugs suitable for mating with the input jacks of a handheld multimeter are disposed within the adapter on the other side of a high thermal resistance zone. Conductors connect these outputs to the input connectors and to the leads of the temperature sensor. A four output version of the adapter is shown for use with a three lead temperature sensor, and a three output version is shown for use with a two lead temperature sensor. The output plugs can paired to be more compact and easier to use through the use of dual-signal single-axis banana plugs.

Temperature compensated adapter for a DMM

An electrical receptacle mountable on and positionable within a substrate has an electrically conductive element that includes a conductive member with deformable electrical leads extending therefrom. The deformable electrical leads have first and second portions with the first portion extending outward from the conductive member and the second portion being adjacent to and approximately parallel with the conductive member. A body of electrically insulating material encapsulates the conductive member about the exterior surface of the conductor with the electrically insulating material having an exterior surface on which is formed support ribs and alignment ribs with the support ribs providing initial support for the electrical receptacle over an aperture formed in the substrate and the alignment ribs providing positioning alignment of the electrical receptacle within the aperture of the substrate. The conductive member may be an elongated tubular shaped conductor or a coaxially disposed, longitudinally split or laterally split conductor suitable for use in a banana type receptacle.

Banana type electrical receptacle

An electrical connector with a female portion defining a bore having an aperture, and a male portion having an elongated member sized to be received in the bore. The female portion has a first flexible contact and an electrically isolated second rigid contact. The male portion has a first flexible contact and an electrically isolated second rigid contact. The connector may be a banana connector with a barrel spring providing conventional contact, and a separate contact at the tip of the male portion.

Dual contact banana connector

A current probe (10) measures a signal current flowing in a conductor (12), which produces a signal flux (14) proportional to the signal current. The probe includes a pair of probe arms (16, 18) that straddle the conductor, a flux shunt (20), a pair of flux diverting arms (22, 24), and a flux link (26). A Hall-effect device (28) senses the amount of flux flowing in the flux shunt. A major portion of the signal flux flows in a preferential path (30) through the flux shunt while a minor portion flows in a flux diverting path (32). The ratio of the amount of the signal flux flowing in the preferential flux path to the diverting path depends on the reluctance in each path, which is determined by air gaps (27, 34). The Hall-effect device drives a current source (40) that provides a diverter current through a pair of flux diverting coils (42, 44) that are wound around flux diverting arms (22, 24) of the current probe. The diverter current produces in the flux diverting path a diverting flux (46) that diverts the signal flux from the flux shunt. The signal current is measured by determining the amount of diverter current required to completely divert the signal flux flowing in the flux shunt.

Direct current measuring apparatus and method employing flux diversion

A split-path isolation amplifier (10) employs a transformer (30) in a high path (26) and a single-input, dual-output closed-loop optocoupler (66) in a low path (24) to achieve a flat, wide frequency response without need for frequency compensation adjustments. In a low path frequency region (106), the optocoupler provides all or most of the signal to the output. The isolation amplifier employs a substantially overlapped crossover frequency region (104) in which the high path signal is applied to a primary winding (28) of the transformer, and the low path signal is applied differentially to secondary windings (40, 42) of the transformer. At frequencies below the crossover frequency range, the signal from the optocoupler dominates as the signal coupled from the primary winding rolls off. At frequencies above the crossover frequency range, the signal coupled from the primary winding dominates as the signal from the optocoupler rolls off. At frequencies within the crossover frequency range magnetic flux components generated by the primary and secondary transformer windings co-act to provide a combined output signal having a flat frequency response. The only adjustments are those required to match the gain of the low path to the gain of the high path and to compensate for any offset in the low path.

Split-path linear isolation circuit apparatus and method

A current probe comprising a Hall device and a secondary winding in a flux linking relationship with a magnetic circuit is self-calibrated by disconnecting the Hall device from the winding, passing a current through the winding so as to induce a magnetic flux in the magnetic circuit, measuring voltage developed by the Hall device in response to linking by the magnetic flux, calculating the Hall gain of the Hall device, and then adjusting the gain of a scaling output amplifier on the basis of the calculated Hall gain to compensate for variation in Hall gain due to changes in operating conditions.

Current probe

The distribution with respect to time of an event defined by the waveform of a repetitive input signal having a magnitude that lies within a predetermined range of values is observed by generating a sample signal at least once during each repetition of the input signal, generating an n-bit digital timing signal representative of the time of occurrence of a sample signal relative to the time of occurrence of the trigger signal, and sampling the repetitive input signal and generating a memory enable signal in the event that the magnitude of the input signal at the time of sampling falls within the predetermined range of values. The memory locations of a memory having 2.sup.n separately addressable memory locations are allocated respectively to the 2.sup.n possible values of the timing signal, and the contents of a memory location of the memory means are incremented by one unit in the event that a memory enable signal is generated in response to a sample signal that is associated with the timing signal to which the location is allocated.

Method and apparatus for evaluating jitter

Measurement accuracy of an oscilloscope is extended by monitoring the temperature within the oscilloscope, and automatically entering a calibration cycle if the temperature varies by a predetermined amount. A temperature sensor is strategically located within the oscilloscope to sense variations in temperature. A first sensed temperature value is stored. Upper and lower temperature limits representing the maximum permissible deviation from the stored value are calculated. Instantaneous temperature values from the sensor are compared with the stored value, and as long as the instaneous values are with the limits, an indication of extended accuracy is provided. If the instantaneous temperature values vary outside the limits, an automatic calibration cycle is initiated. After calibration, a new temperature value is stored and the monitoring process continues to ensure extended accuracy.

Oscilloscope having temperature monitor and recalibration feature to

A resonance compensated unity voltage gain amplifier comprises an input stage and an output stage connected in feedback to the input stage and a series resonance circuit for compensating for the resonance of the output and input stages created by the feedback. Reactance of the series resonance circuit is adjusted to be substantially zero at the resonant frequency of the amplifier. The resonance compensated amplifier is incorporated into a gain selectable amplifier. The resistance on the output stage of the amplifier across which the input voltage is applied via the output voltage may be selectively varied to change the current gain of the amplifier.

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Hillsboro, OR, United States of America

Clifford E Baker