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. 04, 1992
Filed:
Jan. 24, 1991
Jon Fairhurst, Grass Valley, CA (US);
The Grass Valley Group, Inc., Nevada City, CA (US);
Abstract
In a new television signal decoder architecture, a mixer switches between two inputs, A and B, using an envelope function C, according to the relationship: Ouput=A*C+B(1-C), where A is either the composite television signal input in normal operation or a first test signal memory in test signal generation operation, and B is either a fixed blanking level in normal operation or a second test signal memory in test signal generation operation. A test signal generator and blanking sequencer provides the test signals to the two test signal memories and an envelope control signal to the envelope generator telling it when and in which direction to supply the transition envelope to the mixer. A variable electrical length front end is created by a microprocessor that recalls from its memory the timing associated with a particular composite video source and directs a timing circuit to wait an appropriate amount of time before releasing a frame of video stored in a FIFO buffer memory to the rest of the decoder. A bus is shared by sync signals and signals from diagnostic points of interest and is alternatively controlled by the sync generation circuitry during normal operation and the microprocessor during diagnostics.