High frequency optically coupled differential voltage probe with logarithmic response
AssigneeThe United States of America as represented by the Secretary of the Army
InventorGeorge H. Baker
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Abstract
A voltage probe is provided for measuring high frequency transients during lectromagnetic pulse simulator testing of electronic devices. A probe tip module including input terminals for receiving transient voltages, a differential amplifier producing a representative output voltage in response to the transients received and a lamp driver amplifier selectively driving one or another of a pair of light emitting diodes in logarithmic response to the output of the differential amplifier is coupled with the testing geometry. The light output of the diodes is coupled through two respective fiber optics devices to respective photodetector inputs of two signal channels which convert the photodetector outputs to suitable driving signals for a dual trace oscilloscope.
Claims8
Differential voltage probe means comprising:
- a probe module having positive and negative voltages input terminals, differential amplifier and driver circuit means providing voltage output signals as a function of the logarithm of the voltage differences at said input terminals, and first and second light emitting means selectively driven by said circuit means as function of the relative magnitudes of the respective voltages at said input terminals and providing first and second light outputs of intensities proportional to the said voltage differences;
- a dual channel amplifier means comprising first and second photodetector means responsive to the light outputs of said first and second light emitting means, respectively, each photodetector means serving as an input sensor for a respective one of said channels and providing first and second current inputs, respectively, proportional to said first and second light outputs, and first and second current-to-voltage and buffer circuit means comprising said dual channels energized in respective response to said first and second light emitting means for providing output signals proportional to the said voltage differences sensed by said probe module;
- and
- optical coupling means connecting said first and second light outputs of said first and second light emitting means to said first and second photodetector means, respectively.
Dependencies are inferred from the claim text.