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:
Mar. 15, 1988
Filed:
Sep. 20, 1985
Deutsche Thomson-Brandt GmbH., Villingen-Schwenningen, DE;
Abstract
A mixer circuit with a conventional very high frequency circuit for the reception of color television bands I and III, which is connected dependent on the band and which is provided with an NPN transistor. The NPN transistor operates via a collector resistor onto a two circuit band filter. Moire interferences in the band I region expanded for CATV are avoided by having the mixer current used to 0.3 to 0.6 mA via a counter coupling resistor disposed between base and hot end of the resistor 4. Thus the self-interference in band I is reduced by a value of about 60 dB. In case of band III operation the corresponding switching voltage is fed via a series connection of a diode 6 and a resistor 5 to the base and thus the base level is lifted up to higher mixing current, since in band III self-interferences cannot occur in the case of the presence of signals.