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:
Jun. 12, 2012
Filed:
Jun. 20, 2007
Tsutomu Tanaka, Ora-gun, JP;
Mutsuki Niki, Saitama, JP;
Tsutomu Tanaka, Ora-gun, JP;
Mutsuki Niki, Saitama, JP;
Sanyo Electric Co., Ltd., Osaka, JP;
Abstract
In a VIF circuit for synchronously detecting a picture signal from an AM-modulated PIF signal, the accuracy of a picture signal to be demodulated is maintained even in a state of overmodulation. A comparator () determines whether the picture signal exceeds V, which is a state of overmodulation. In a period in which the signal is less than or equal to V, a switch circuit () inputs an output voltage of an APC filter () to a VCO (), and a PLL is formed. The PLL operates so as to lock onto the PIF signal, and reproduces a carrier wave. On the other hand, in a period in which the signal exceeds V, the switch circuit () inputs an output voltage Vof an SH circuit () to the VCO (). The SH circuit () holds the voltage of the APC filter () that is in a locked state in a horizontal synchronizing period and uses the voltage to control the VCO (), whereby free run and frequency drifting are minimized.