CIRCUIT ARRANGEMENT FOR A WIDE-BAND VHF-UHF TELEVISION DOUBLE SUPERHETERODYNE RECEIVER

摘要

ABSTRACT OF THE DISCLOSURE:The signal transmission lines in a double conversionstage for a double superheterodyne VHF-UHF television receiverare mainly constructed of unbalanced circuits rather thanbalanced circuits. The circuit arrangement comprises a wide-band amplifier for receiving the incoming carrier frequency,first and second frequency conversion stages, and an inter-mediate frequency amplifying stage. Connections between thewideband amplifier and the first frequency conversion stageas well as connections between the second frequency conversionstage and the intermediate frequency amplifying stage areachieved by means of unbalanced circuits. Each of the firstand second frequency conversion stages comprises a mixerconstructed of a single balanced circuit, a local oscillatorand an unbalanced/balanced conversion circuit interposedtherebetween. A filter circuit, comprising a band-passfilter and a low-pass filter, interposed between the firstand second frequency conversion stages, effectively blocksspurious signals.