| 摘要 |
PURPOSE:To realize transmission with excellent S/N and transmission frequency and characteristic and less transmission bit rate by obtaining digitized difference data from a sequential difference of an analog original signal, detecting inversion/non-inversion with a polarity to a sample just before at each sampling of the difference data to discriminate the substantial maximum frequency of the analog original signal. CONSTITUTION:A pattern discrimination 50 discriminates whether or not the polarity inversion is consecutive twice or over in one block to discriminate whether or not a frequency component exceeding a half of the sampling frequency is included, and when the output of the discriminator 50d is at high level, a selector 6 selects an output of the 1st converter 3 and 7-bit data in a frequency fs becomes transmission data with respect to the block. When at a low level, the output of the 2nd converter 4 is selected and 14-bit data in a frequency fs/2 becomes the transmission data with respect to the block.
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