| 摘要 |
PROBLEM TO BE SOLVED: To provide a PB signal receiver with less erroneous operation where frequency detection accuracy is improved and the judgment error in the effective length of PB signals is reduced. SOLUTION: The effective judgment of received PB signals is made by an effective signal judgment means 6 based on the continuation time of an identification signal being extracted by a first frequency detection means and a second frequency detection means 3 for detecting frequency at a small period, and the coincidence judgment among a frequency being detected by the first and second frequency detection means 2 and 3, and a frequency being detected over a number of periods by third and fourth frequency detection means 4 and 5.
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