GATE-2018 (24) :Wyllie – Time average equation

GATE-2009

27. A seismic signal is recorded in a frequency band, 50-100Hz . The sampling interval (ms) to avoid aliasing would be

 A)5                            

B)60                    

C)40                             

D)20

Solution:

Highest frequency recorded in this band( 50- 100Hz)  is = 100Hz

The Nyquist rate is the minimum sampling rate required to Avoid aliasing,

 equal to twice the highest frequency contained With in the signal

f_N = 2 f_max

   = 2 * 100

   = 200 Hz

Thus, sampling interval = 1 / 200 

 

                                    = 0.005 s

                                    = 5 ms