In a message dated 1/9/00 12:42:38 PM Pacific Standard Time, karlc@....... writes: >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> My questions are: 1. Given that the instrument probably does not have equal time delay response, is there a standardized frequency for which seismometer time delay measurements are made? 2. If pulse response is used (dropping the object on the floor), can the seismometer output just be bandpass filtered to the desired frequency, and the delay measured? If so, what kind of bandpass filtering should be used, and should its delay be considered? 3. In doing the pulse response measurement, is the proper delay measurement made to the first noticable change in the output, or to some other point in the output waveform? Any help or suggestions are appreciated. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I have invented a device to do just that on a vertical geophone. I use a DC voltage and apply it to the geophone output. This lifts the coil (or depresses it depending on the polarity), then this voltage is switched off and the output is connected to an oscilloscope or some othe devicee that can immediately measure the coil voltage output as it returns to the normal resting place. One can use this to measure the natural frequency and relative amplitude of the geophone. You can also measure the damping factor. George Erich on the + side http://hometown.aol.com/gee777/myhomepage/profile.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>