US 5,180,973 A · Self-calibrating CRT measuring instrument

Abstract

A measuring instrument having a programmable time base circuit including a digitally adjustable integrator for generating a plurality of sawtooth voltages for the different operational states of a CRT display apparatus. The measuring instrument has an automatic calibration procedure for calibrating the various time base settings. A microcontroller drives the digitally adjustable integrator during calibration of the measuring instrument so as to calibrate the time base circuit for each operational state. A detection circuit detects whether the time base circuit is calibrated and provides a status signal to cause a digital memory in the microcontroller to store calibration values determined in the calibration procedure. During normal operation of the measuring instrument, the microcontroller drives the integrator of the time base circuit using the stored calibration values for the corresponding operational states.

Claims8

Dependent claims

A self-calibrating measuring instrument having a calibration state and operational states and comprising;

a display system for displaying an input signal and controlled by a time base circuit, wherein the time base circuit comprises a digitally adjustable integrator for generating sawtooth voltages with different slopes corresponding to different operational states of the display system, a programmed means which, in the calibration state, drives the digitally adjustable integrator with a calibration signal for the various operational states such that the time base circuit is calibrated for each operational state, an output of the time base circuit being coupled to a detection circuit for detecting whether the time base circuit is calibrated in an operational state thereby to derive a status signal which is supplied to the programmed means and which indicates whether the time base circuit has been calibrated, digital storage means for storing calibration values determined in the calibration state, and wherein during normal operation of the measuring instrument, the programmed means drive the integrator with the relevant calibration values for the corresponding operational states.

A measuring instrument for measuring and displaying a signal wherein the measuring instrument has a calibration mode, said instrument comprising;

a display system for displaying a signal input to the measuring instrument, said display system having a plurality of operational states,
a time base circuit for controlling the display system, wherein the time base circuit includes a digitally adjustable integrator for generating sawtooth voltages with different slopes as a function of a selected operational state,
a first programmed means including means for providing a calibration signal for calibrating the time base circuit in any of the operational states when the measuring system is in the calibration mode,
digital storage means for storage of calibration values determined in the calibration mode, and
a second programmed means including means for providing, during normal operation of the measuring instrument, said integrator with calibration values determined during the calibration mode and stored in the digital storage means.

2 more elements

Dependencies are inferred from the claim text.

Self-calibrating CRT measuring instrument

Life of this patent

Self-calibrating CRT measuring instrument

Life of this patent

Abstract

Claims8