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(11) | EP 0 503 202 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Method of controlling RDS receiver |
(57) To permit a user to listen to a broadcasting program of the same network in good
receiving conditions when a multipath occurs on an RDS broadcasting wave that is being
received at an intermediate field intensity, it is judged whether or not a lock detection
signal is produced from a lock detector every unit time during reception of a broadcasting
wave; and when the frequency of judgement in a set time that no lock detection signal
is produced is greater than a reference value, frequency data of one station of that
group of network stations to which a broadcasting station of the receiving broadcasting
wave belongs is read out from a memory and the reception frequency is switched to
the frequency indicated by the current frequency data read out. To ensure quick transition
to the reception of the RDS broadcasting wave that can assure good receiving conditions
even when a vehicle is driving in a tunnel or a mountainous area, an average level
of a reception signal level of a currently receiving broadcasting wave may be calculated
in a predetermined time at every given timing, and when a previous average level is
higher than a first predetermined value and a current average level is lower than
a second predetermined value smaller than the first predetermined value, or when the
previous average level is lower than the second predetermined value and the current
average level is higher than the first predetermined value, frequency data of one
station of that network station group to which a broadcasting station broadcasting
the currently receiving broadcasting wave belongs is read out from the memory, and
the reception frequency is switched to the frequency indicated by the read out frequency
data. Further, to ensure quick transition to the reception of the RDS broadcasting
wave that can assure good receiving conditions even when the reception of the currently
receiving RDS broadcasting wave becomes poor, when such poor reception of the currently
receiving RDS broadcasting wave occurs, those pieces of frequency data which can assure
a field intensity equal to or higher than a set level are first extracted from a frequency
data list stored in the memory, then that piece of the extracted frequency data which
has the highest reception signal level is selected, and the reception frequency is
switched to the frequency indicated by the selected frequency data. |