公开(公告)号：US3562412A

公开(公告)日：1971-02-09

申请号：US3562412D

申请日：1969-03-26

Applicant: ADMIRAL CORP

Inventor： CALLAWAY EMORY C

IPC: H03G9/24 ,  H04N5/44 ,  H04N5/50 ,  H04N9/00

CPC classification number: H04N5/4446 ,  H03G9/24

Abstract: The first IF stage in a color television receiver comprises a transistor biased for forward AGC operation and having a collector impedance varying inversely with the strength of a selected television signal. A double-tuned circuit, incorporating the transistor collector impedance, displays a frequency characteristic having a maximum response approximately midway between two preselected optimum frequencies when the collector impedance is small, and maximum responses near both optimum frequencies when the collector impedance is large, whereby the receiver can be desirably fine tuned even under weak signal conditions.