Direction of arrival estimation apparatus and variable directional signal receiving and transmitting apparatus using the same

摘要

A direction of arrival (DOA) estimation apparatus of the present invention comprises a plurality of A/D converters that converts a plurality of complex base band signal obtained from the receiving signals of a plurality of antenna elements to respective complex digital signals, a plurality of low pass filters that outputs complex low pass signals with attenuated high frequency components of respective complex digital signals, a plurality of down samplers that outputs complex down sampled and multiplied signals by down sampling the complex low pass signals and multiplying by integral number of sampling intervals of respective A/D converters, and a data transfer section that stores respective complex down sampled signal thus obtained from respective antenna elements temporary and then transfers the data. A variable directional signal receiving and transmitting apparatus of the present invention performs an antenna directivity control based on the output data from the above data transfer section. With the composition of the present invention, an amount of data required for a DOA estimation process section is decreased and a composition of a data transfer section is simplified. With the composition of the present invention, a deterioration of an accuracy of direction estimation becomes minimum despite the simplification of the apparatus. Furthermore, a favorable receiving and transmitting quality is obtained by applying the DOA estimation apparatus for a transmitting and receiving apparatus.