| 摘要 |
PROBLEM TO BE SOLVED: To provide an information recording and reproducing device having a noise filter varying frequency characteristic according to the frequency of a digital audio signal. SOLUTION: The variable capacitance element of the noise filter varies capacitance by a DC control voltage and can vary frequency characteristics of the noise filter. A control voltage output unit outputs the DC control voltage corresponding to the frequency of the digital audio signal output from an audio decoder. Therefore, when the frequency of the digital audio signal output from the audio decoder increases, the DC control voltage increases and then capacitance of the variable capacitance element is reduced, so that a cutoff frequency of the noise filter increases. When the frequency of the digital audio signal is lower, the DC control voltage is reduced and then the capacity of the variable capacitance element increases, so that the cutoff frequency of the noise filter decreases. COPYRIGHT: (C)2008,JPO&INPIT
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