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:
Aug. 22, 1989
Filed:
Nov. 06, 1985
Paul M Trethewey, Penn Valley, CA (US);
The Grass Valley Group, Inc., Grass Valley, CA (US);
Abstract
An apparatus for smoothing an abrupt change in signal level generates a control signal having a curvilinear ramp shape. An amplifier has a step input signal applied to a non-inverting input, a delayed slope control signal applied to a bias terminal, and the output of the amplifier fed back to an inverting input. An RC series circuit is connected between the output of the amplifier and a reference potential, with the control signal taken from the node between the resistor and capacitor. The amplifier is saturated by the step input signal, and is subsequently turned on by the delayed slope control signal so that the amplifier acts initially as a current source for the RC circuit until the slope control signal reaches its full value. Then the RC circuit charges linearly until the intercept voltage of the step input is approached, at which point the amplifier comes out of saturation and acts as a voltage source to exponentially charge the capacitor to the intercept voltage.