SUNULL - create null (all zeroes) traces	 		

 sunull nt=   [optional parameters] >outdata			

 Required parameter						
 	nt=		number of samples per trace		

 Optional parameters						
 	ntr=5		number of null traces to create		
 	dt=0.004	time sampling interval			

 Rationale: It is sometimes useful to insert null traces	
	 between "panels" in a shell loop.			

 See also: sukill, sumute, suzero				


 Credits:
	CWP: Jack K. Cohen

 Trace header fields set: ns, dt, tracl