Patent ID: 6631341
Filing Date: 2003-10-07
Classification: G06K

Abstract:
A signal analyzing apparatus comprising:a local oscillator for oscillating a local oscillation signal; a signal mixer for mixing a measured signal with the local oscillation signal from the local oscillator to exact time span sweeping for fixing a frequency of the local oscillation signal; a resolution bandwidth RBW filter in which a bandwidth is set so as to selectively pass a frequency component of only a desired signal bandwidth of the measured signal that has been frequency-converted into a normalized intermediate frequency signal; a waveform detector for detecting a signal passing through the RBW filter; an analog/digital A/D converter for sampling the signal detected by the waveform detector at a predetermined sampling rate at which a Nyquist frequency is within the frequency bandwidth of the RBW filter, thereby converting the sampled signal into digital data; a data storage section for storing digital data of a time domain converted by the A/D converter; a signal processing section for re-sampling the digital data of the time domain stored in the data storage section so as to enable reproduction of a bandwidth of the signal detected by the waveform detector, thereby generating arbitrary time data to measure a time change of the bandwidth of the measured signal limited to the normalized bandwidth by the RBW filter; and a display section for displaying the arbitrary time data generated by the signal processing section while time and amplitude are defined on horizontal and vertical axes on a display screen.