Capture frequency decision methods and receivers
First Claim
1. A capture frequency decision method of deciding a capture frequency by executing a frequency search in which a correlation operation on a received Code Division Multiple Access signal is performed at a plurality of search frequencies, the method comprising:
- selecting a correlation integration time;
executing a first frequency search of performing the correlation operation using the selected correlation integration time at a plurality of first search frequencies;
determining a side lobe frequency offset for a second frequency search, wherein the side lobe frequency offset varies with the selected correlation integration time of the first frequency search;
setting a frequency for a side lobe check on the basis of the determined side lobe frequency offset;
selecting a plurality of second search frequencies including the frequency for the side lobe check on the basis of a result of the first frequency search;
executing the second frequency search of performing the correlation operation at the plurality of selected second search frequencies including the frequency for the side lobe check; and
deciding a capture frequency by executing a third frequency search using a result of the second frequency search,wherein an interval between frequencies of the plurality of second search frequencies including the frequency for the side lobe check is narrower than an interval between frequencies of the plurality of first search frequencies.
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Abstract
A capture frequency decision method of deciding a capture frequency by executing a frequency search in which a correlation operation on a received signal, which is a CDMA (Code Division Multiple Access) signal, is performed at a plurality of search frequencies, includes: executing a first frequency search; setting a frequency for a side lobe check on the basis of a correlation integration time used in the first frequency search; selecting a plurality of search frequencies including the frequency for a side lobe check on the basis of a result of the first frequency search; executing a second frequency search of performing the correlation operation at the plurality of selected search frequencies; and deciding a capture frequency by executing a third frequency search using a result of the second frequency search.
6 Citations
10 Claims
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1. A capture frequency decision method of deciding a capture frequency by executing a frequency search in which a correlation operation on a received Code Division Multiple Access signal is performed at a plurality of search frequencies, the method comprising:
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selecting a correlation integration time; executing a first frequency search of performing the correlation operation using the selected correlation integration time at a plurality of first search frequencies; determining a side lobe frequency offset for a second frequency search, wherein the side lobe frequency offset varies with the selected correlation integration time of the first frequency search; setting a frequency for a side lobe check on the basis of the determined side lobe frequency offset; selecting a plurality of second search frequencies including the frequency for the side lobe check on the basis of a result of the first frequency search; executing the second frequency search of performing the correlation operation at the plurality of selected second search frequencies including the frequency for the side lobe check; and deciding a capture frequency by executing a third frequency search using a result of the second frequency search, wherein an interval between frequencies of the plurality of second search frequencies including the frequency for the side lobe check is narrower than an interval between frequencies of the plurality of first search frequencies. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A receiver that captures a CDMA signal, which is a received signal, by deciding a capture frequency by executing a frequency search of performing a correlation operation on the CDMA signal in a frequency direction, the receiver comprising:
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a first search executing section that selects a correlation integration time and executes a first frequency search of performing the correlation operation using the selected correlation integration time at a plurality of first search frequencies; a setting section that determines a side lobe frequency offset for a second frequency search, and sets a frequency for a side lobe check on the basis of the determined side lobe frequency offset, wherein the side lobe frequency offset varies with the selected correlation integration time of the first frequency search; a second search frequency selecting section that selects a plurality of second search frequencies including the frequency for the side lobe check on the basis of a result of the first frequency search; a second frequency search executing section that executes the second frequency search of performing the correlation operation at the plurality of selected search frequencies including the frequency for the side lobe check; and a capture frequency deciding section that decides a capture frequency by executing a third frequency search using a result of the second frequency search, wherein an interval between frequencies of the plurality of second search frequencies including the frequency for the side lobe check is narrower than an interval between frequencies of the plurality of first search frequencies. - View Dependent Claims (10)
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Specification