| 摘要 |
<P>PROBLEM TO BE SOLVED: To generate a band limited impulse waveform by using a waveform forming means which operates at a frequency lower than a conventional frequency. <P>SOLUTION: This impulse waveform generating apparatus comprises an oscillator 1 for generating a reference signal having a center frequency F0 in a frequency band of an impulse to be generated, a timing matching circuit 3 for generating a phase shift signal resulting from shifting a phase of the reference signal at an angle of 90 degrees, a frequency demultiplier 5 for dividing a frequency of the phase shift signal and obtaining a timing signal having a frequency component having the frequency width of an impulse to be generated, a storage means for storing a shape table for a waveform in advance, a waveform forming section 7 for forming a waveform in synchronism with the timing signal according to information in the shape table, a low-pass filter 9 for obtaining an envelope signal from an output signal of the waveform forming section 7, and a waveform generating section 10 for changing an amplitude of the reference signal according to a value of the envelope signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
