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:
Jan. 10, 1989
Filed:
Jul. 02, 1986
Hitoshi Takai, Hirakata, JP;
Noriaki Morotomi, Fujisawa, JP;
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
In a transmission system of signals including amplitude-modulated television signals, a pilot signal of a specific amplitude is supplied at a first place in the transmission system, and at a second place in the transmission system, the pilot signal having been subjected to a cross modulation due to nonlinearity of the transmission system from the first place to the second place is extracted. A rectifier picks up an envelope of the cross modulated pilot signal. In consequence, out of the envelope, the fundamental wave component or a higher harmonic component of the horizontal scanning frequency of the transmitted television signal is extracted by using a filter of an extremely narrow band. By detecting the increase in the level of this removed signal, an increase in distortion due to an excessive level of the transmission signal which causes a problem in the transmission system is detected.