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Method and device for recognising and, if necessary, replacing an m-bit synchronisation word preceding a digitised image content of n APPROX 106 bits
Method and device for recognising and, if necessary, replacing an m-bit synchronisation word preceding a digitised image content of n APPROX 106 bits
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机译：用于识别和替换n位约10 <6>位的数字化图像内容之前的m位同步字的方法和设备
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摘要
During the transmission of digitised image signals in data packets of n APPROX 106 bits and only one m-bit synchronisation word per frame, the risk of synchronisation to pseudosynchronisation words accidentally produced by the image content arises, in addition to the risk of transmission errors in the synchronisation word itself. To avoid both risks, a vertical identification signal VK1 is extracted from the m-bit synchronisation word with m 10 transmitted in the vertical blanking interval of k APPROX 103 bits. This identification signal starts an n-bit counter 7 and disables a gate circuit 5, 6, previously opened for the period of o-bits (m o k) of the assumed occurrence of the vertical identification signal VK1 by the preceding frame end pulse of this counter, with respect to pseudo-identification signals which can be accidentally extracted from the image content. An o-bit counter 10 started by the frame end pulse replaces with its output pulse VK2 a failed vertical identification signal VK1. After the vertical identification signal has been lacking several times, a p-bit counter 11, operated by the frame end pulse and in each case reset by the vertical identification signal VK1, inhibits its replacement by the output pulse of the o-bit counter.
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