| 摘要 |
PURPOSE:To simplify a signal processing circuit which is necessary for decoding by decoding a data signal which has been differential phase-shifted and modulated through the use of a piezo electric element. CONSTITUTION:A signal s (bit) which has been differential phase-shifted and modulated is supplied to a piezoelectric device 10. A synthesis signal which is obtained by subtracting signals S (bit) and S(bi-1t) is outputted from an adder 3, and a synthesis signal which has been obtained by adding both is outputted from an adder 4. The outputs of the adders 3 and 4 are given to pulse generators 7 and 8 through envelope detectors 5 and 6. The generators 7 and 8 generate output signals 7a and 8a by level decision which envelope signals 5a and 5b has previously decided, and supply them to a data assembly unit 9. It logically judges the logical level of the output signals 7a and 8a and an output signal 9a, whereby an output in which original data is decoded is obtained.
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