| 摘要 |
PURPOSE:To simplify the constitution of a deciding device for the identity and to cope with a larger time difference, by deciding zero cross waves obtained from a zero cross detector with a controller directly relating to a car radio receiver. CONSTITUTION:A controller 17 checks for outputs of voltage comparators 40, 41 and starts fetching of two zero crossing waves being outputs of zero cross detectors 32, 33, after a signal having sufficient sound level (hereinafter, called ''effective''). The data fetching operation is performed for sufficient number of times for the same identity, i.e. N+x times, and the output of the voltage comparators 40, 41 is confirmed for both ''effective'' at each data fetch. When the data fatch is finished, the controller 17 clears a counter 62 at first into zero as initial value, compares data bits of the same address of data memories A60 and B61 sequentially, and adds ''1'' to the contents of the counter 62 when one is a logical value ''1'' and the other is ''0''. |
