def process_step(self, step, stream):
"""Filters stream for one step.
Filters all traces in stream.
Parameters
----------
step : array element
step holding variables for one filtering operation
stream : obspy.core.Stream
stream of data to filter
Returns
-------
out : obspy.core.Stream
stream containing 1 trace per original trace.
"""
# gather variables from step
input_sample_period = step["input_sample_period"]
output_sample_period = step["output_sample_period"]
window = np.array(step["window"])
decimation = int(output_sample_period / input_sample_period)
numtaps = len(window)
window = window / sum(window)
out = Stream()
for trace in stream:
starttime, data = self.align_trace(step, trace)
# check that there is still enough data to filter
if len(data) < numtaps:
continue
filtered = self.firfilter(data, window, decimation)
stats = Stats(trace.stats)
stats.delta = output_sample_period
stats.data_interval = step["data_interval"]
stats.data_interval_type = step["data_interval_type"]
stats.filter_comments = step["filter_comments"]
stats.starttime = starttime
stats.npts = len(filtered)
trace_out = self.create_trace(stats.channel, stats, filtered)
out += trace_out
return out
