Correction for instrument response 

# prior to making correction, response parameters need to be loaded into trace headers:

*call	resp	RESP_file_name

# After this, response corrections can be performed at any stage in data processing:
 
*call	filter
resp	displ		# also transform the data to gropund displacement
			# alternitavely, instead of 'displ', use 'vel' for output velocity
			# or 'accel' for acceleration