Stevens, Davis, Miller & Mosher
Signal detector circuit
 A circuit for detecting the presence or absence of a television receiving signal is disclosed, wherein a detection output for automatic frequency control is compared with first to fifth levels. A low-level output is produced when the detection output is lower than the fifth level; an intermediate-level output is produced when the detection output is between the fifth and fourth levels; a low-level output is produced when the detection output is between the third and second levels; an intermediate-level output is produced when the detection output is between the second and first levels; and a high-level output is produced when the detection output is higher than the first level, thus producing an output signal of three-digit level from a single output terminal. 
Matsushita Electric Industrial Co., Ltd.
H H
H03J H03J
inventional inventional
Kazumi Masaaki
Kawashima Fujita