| 摘要 |
The invention provides a carrier recovery circuit which reduces the amount of calculation processing recovered to renew the tap coefficients of an adaptive filter to achieve improvement performance at low signal-to-noise ratio and make high speed pull in possible. Tap coefficients of variable coefficient filter 12 of adaptive line enhancer 1 are blocked into a plurality of blocks, and switches of switch circuit 14 individually corresponding to the blocks are selected by coefficient renewal control circuit 3 and renewal of the tap coefficients of the selected block is executed by adaptive algorithm circuit 13. Since all tap coefficients need not necessarily be renewed at a time in each symbol cycle, only the tap coefficients of the selected block are renewed. Thus although the adaptive speed of the adaptive emission line emphasizer decreases, the adaptive line enhancer can be constructed with a narrower band. Further, by varying the number of blocks to be selected in response to frame synchronizing information, prior to establishment of frame synchronization the number of blocks to be selected can be reduced and high speed pull in is realized. <IMAGE> |
