| 摘要 |
This invention relates to an information read device for reading the information of a coded AC signal. The information read device for reading the information of a coded AC signal, wherein a bit "1" is represented by one cycle of an AC signal and a bit "0" is represented by an absence of said AC signal, comprises a first square wave converter to generate a first square wave signal corresponding to positive components of said coded AC signal, a second square wave converter to generate a second square wave signal corresponding to negative components of said coded AC signal, and gate means to selectively pass one of said first and second square wave signals so that said first square wave signal is passed when said AC signal of said coded AC signal begins with a negative component while said second square wave signal is passed when said AC signal of said coded AC signal begins with a positive component, comprising means to modify said coded AC signal so that said information is read out on a level of negative component of said coded AC signal when it begins at a positive polarity and on a level of positive component of said coded AC signal when it begins at a negative polarity.
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