| 摘要 |
1528483 Data transmission; distortion correction; automatic tuning control SANGAMO WESTON Inc 7 Oct 1975 [7 Oct 1974] 40932/75 Headings H4P and H3A An arrangement for reconstructing distorted incoming signals comprises a filter including a delay with a defined transfer function with a means for deriving a timing signal which adjusts or tunes the filter delay corresponding to the rate of incoming signals. Input NRZ signals distorted by noise are applied through a buffer amplifier to a matched filter 20 having a 1 bit delay 22, matched to the type of modulation, which delay may comprise charge transfer (e.g. "bucket brigade") devices. A summing amplifier 24, whose output is integrated at 26, receives delay input and output signals; integrator 26 output represents mark/space signals which are compared at 30 with a reference voltage 32 but these are not synchronous with incoming signals. Synchronism is provided by a flip-flop 34 receiving clock pulses from a frequency divider 36 connected in a phase locked loop arrangement 36, 38, 40 also receiving delay line output in a phase comparator 42 which adjusts loop frequency. Output of loop is also fed back to delay 22 so that it maintains a 1 bit delay irrespective of variations in input bit rate; V.C.O. 46 runs at an integral multiple N of bit rate (e.g. N = 32) which is N in 36. |
