The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 15, 1992
Filed:
Apr. 24, 1991
Thomas J Zamborelli, Colorado Springs, CO (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A passive test probe apparatus 100 which provides high impedance and a relatively flat frequency response over a wide bandwidth. The probe apparatus 100 uses standard, non-lossy coaxial cable 130. The probe apparatus 100 employs a low capacitance probe tip 102 designed to minimize stray probe tip capacitance. The probe apparatus 100 uses a front-end (tip) resistor R.sub.t in series with a conventional RC tip network 240. The tip resistor R.sub.t provides two functions: First, it establishes a minimum input impedance for the probe input, and secondly, it provides approximately 80% of the high frequency attenuation when working into the cable characteristic impedance. In addition, a technique is described for determining an optimum length of coaxial cable 130 to be used in the probe apparatus 100. When the cable length is selected in accordance with the present invention, the crossover dip and other transmission line signal distortion effects are minimized.