| 摘要 |
PURPOSE:To obtain a signal point and a zero cross point from a filter by using a tap coefficient control circuit so as to control a tap coefficient of a non-cyclic filter in an interpolation circuit used for a clock phase error check in clock synchronization. CONSTITUTION:A sample circuit 6 samples a signal transmitted at a transmission period TB in a sampling period T independently of the period TB and its output is fed to the non-cyclic filter 7. The delay circuit 70 of the filter 7 applies N-tap's delay and a tap coefficient storage circuit 71 includes a value of the TB (signal point) and the TB/2 (zero cross point) for N-tap's share. Each tap coefficient and a sample value delayed are multiplied by multiliers 73, 74,...78, added (72) and outputted. In this case, a tap coefficient control circuit 8 gives a control to calculate the signal point and the zero cross point. The circuit 8 is used to obtain the signal point and the zero cross point from one filter without increasing the hardware. |
