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