H04M1/00—Substation equipment, e.g. for use by subscribers
H04M1/78—Circuit arrangements in which low-frequency speech signals proceed in one direction on the line, while speech signals proceeding in the other direction on the line are modulated on a high-frequency carrier signal
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Engineering & Computer Science
(AREA)
Signal Processing
(AREA)
Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo
(AREA)
Combination conventional telephony and high-bit-rate digital channel transmission system comprising high pass filters which comprise both first order and second order high pass filters