Channel level adjusting apparatus

Claim 1

In a channel level adjusting apparatus having an input terminal and an output terminal wherein television signals of a plurality of channels are applied to said input terminal, a group of the television signals on a plurality of the channels being different in input amplitude level from one another by a negligibly small amount and the television signal of a remaining channel differing in input amplitude level from the television signals of the group by an amount not negligible, and wherein the amplitude levels of all the television signals are adjusted to be closer to each other for delivery to said output terminal, the improvement comprising a first circuit path from said input terminal to said output terminal including filter means for passing at least one of the television signals having the higher input level of (i) the television signals of said group of channels and (ii) the television signal of said remaining channel; attenuation means provided in said first circuit path; a second circuit path from said input terminal to said output terminal for passing the television signals of all said channels from said input terminal to said output terminal; phase shifting means in one of said circuit paths for phase shifting signals passing therethrough 180 degrees; and mixer means for combining the signals passed through said first and through said second circuit paths after said phase shifting and attenuation whereby the amplitude level of the television signals delivered to said output terminal are made more nearly equal to one another than are said signals applied to said input terminal.