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NARROW BAND DIGITAL FILTER, SPECTRUM ANALYZER, DOPPLER FREQUENCY ESTIMATE DEVICE AND CRUST IDENTIFICATION DEVICE, EARTH MAGNETISM IDENTIFICATION DEVICE AND CRUST ESTIMATE DEVICE AND EARTH MAGNETISM ESTIMATE DEVICE
NARROW BAND DIGITAL FILTER, SPECTRUM ANALYZER, DOPPLER FREQUENCY ESTIMATE DEVICE AND CRUST IDENTIFICATION DEVICE, EARTH MAGNETISM IDENTIFICATION DEVICE AND CRUST ESTIMATE DEVICE AND EARTH MAGNETISM ESTIMATE DEVICE
PURPOSE: To make a calculation time per sample period independent of the number of taps by forming a spectrum analyzer with a narrow band digital filter. ;CONSTITUTION: The spectrum analyzer is formed with a narrow band finite impulse response type digital filter in which a coefficient for each tap is given as a product among a trigonometric function, a complex variable exponential function and a real coefficient power whose absolute value is the '1' or below. An input signal is given to synthesis filters 1-3 and output signals from the synthesis filter group are all fed to a frequency separator 4, from which a spectrum separate signal resulting from multiplication between said received signal and a frequency separate matrix is outputted. Thus, a calculation time per one sample period is made independent of the number of taps and indepedent of the initial conditions of the filters. Furthermore, since the initial state of the filter is neglected after the lapse of a prescribed time, it is not required to determine the initial condition to be a prescribed condition.;COPYRIGHT: (C)1995,JPO
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