| 摘要 |
PURPOSE:To form a stereophonic echo erasing device having two kinds of echo erasing circuits by erasing an echo of a sum signal and a difference signal of a right channel and a left channel, respectively. CONSTITUTION:Both receiving signals Rin, Lin from transmission lines 21r, 21l are added by an adder 28 and supplied to a pseudo echo signal generating circuit 31a of a sum signal echo erasing circuit 31, and also they are subtracted by a subtracting circuit 29 and inputted to a pseudo echo signal generating circuit 32a of a difference signal echo erasing circuit 32. On the other hand, each output of amplifying circuits 18r, 18l is added by an adder 33 and inputted to a subtracting circuit 31b, and also subtracted by a subtracting circuit 34 and supplied to a subrtracting circuit 32b. Each output of the echo erasing circuits 31, 32 is inputted to the pseudo echo signal generating circuits 31a, 32a, also subtracted mutually by a subtracting circuit 35, and added mutually by an adder 36. Each output of the subtracting circuit 35 and the adder 36 sets a signal level to 1/2 by attenuating circuits 37, 38, and it is sent out to transmission lines 19r, 19l. |
