In cable modem termination systems and other information transmission systems, a method for changing the interleave depth associated with each data stream is provided. A slide ring, which is made of a plastic with embedded ferromagnetic metal parts is disposed in the gap. , and has a small dielectric constant, a low loss, and a small temperature constant at capacitance. Further, the collar is coated for protection from the elements. , current induced in the substrate by the signal, the region of the substrate is characterized. A capture unit captures a synchronous timing of the receiver signal on the basis of a correlation value which is worked out by a delayed correlation computing unit.