SeisComP3 supports string based filter definitions. This section covers available filters and their parameters.
The filter definition supports building filter chains (operator >> or >) as well as combining them with basic mathematical operators like +, , *, /, ^ (power) and   (absolute value).
A(1,2)>>(B(3,4)*2+C(5,6,7))>>D(8)
where A, B, C and D are different filters configured with different parameters. If a sample is filtered it passes the following stages:
s = a sample
 filter s with A: sa = A(1,2)(s)
 filter sa with B: sb = B(3,4)(sa)
 sb = sb * 2
 filter sa with C: sc = C(5,6,7)(sa)
 add sb and sc: sbc = sb + sc
 filter sbc with D: sf = D(8)(sbc)
sf = final sample
The default filter applied by scautopick is
RMHP(10) >> ITAPER(30) >> BW(4,0.7,2) >> STALTA(2,80)
It first removes the offset. Then an ITAPER of 30 seconds is applied before the data is filtered with a 4th order butterworth bandpass with corner frequencies of 0.7 Hz and 2 Hz. Finally an STA/LTA filter with a shorttime time window of 2 seconds and a longterm time window of 80 seconds is applied.
The following filter functions are available. If a filter function has no parameters it can be given either with parentheses (eg DIFF()) or without (eg DIFF).
Calculates the average of preceding samples.
Parameters:  timespan  Time span in seconds 

Butterworth Bandpass filter (BW) realized as a causal recursive IIR (infinite impulse response) filter. An arbitrary bandpass filter can be created for given order and corner frequencies.
Parameters: 


Butterworth lowpass filter realized as a causal recursive IIR (infinite impulse response) filter.
Parameters: 


Butterworth highpass filter realized as a causal recursive IIR (infinite impulse response) filter.
Parameters: 


Butterworth highlowpass filter realized as a combination of BW_HP() and BW_LP().
Parameters: 


Differentiation filter realized as a recursive IIR (infinite impulse response) differentiation filter.
The differentiation loop calculates for each input sample s the output sample s':
s' = (sv1) * dt
v1 = s;
Integration filter realized as a recursive IIR (infinite impulse response) integration filter. The weights are calculated according to parameter a in the following way:
a0 = ((3a)/6) * dt
a1 = (2*(3+a)/6) * dt
a2 = ((3a)/6) * dt
b0 = 1
b1 = 0
b2 = 1
The integration loop calculates for each input sample s the integrated output sample s':
v0 = b0*s  b1*v1  b2*v2
s' = a0*v0 + a1*v1 + a2*v2
v2 = v1
v1 = v0
Parameters:  a  Coefficient a 

A onesided cosine taper.
Parameters:  timespan  The timespan in seconds. 

A highpass filter realized as running mean highpass filter. For a given time window in seconds the running mean is subtracted from the single amplitude values. This is equivalent to highpass filtering the data.
Running mean highpass of eg 10 seconds calculates the difference to the running mean of 10 seconds.
Parameters:  timespan  The timespan in seconds 

A simulation of a 5second seismometer.
Parameters:  type  The data type: 0 (displacement), 1 (velocity) and 2 (acceleration) 

A STA/LTA filter is the ratio of a shorttime average to a longtime average calculated continuously in two consecutive time windows. This method is the basis for many trigger algorithm. The shorttime window is for detection of transient signal onsets whereas the longtime window provides information about the actual seismic noise at the station.
Parameters: 


The simulation filter of a WoodAnderson seismometer. The data format of the waveforms has to be given for applying the simulation filter (displacement = 0, velocity = 1, acceleration = 2), e.g. WA(1) is the simulation on velocity data.
Parameters:  type  The data type: 0 (displacement), 1 (velocity) and 2 (acceleration) 

The instrument simulation filter of a WorldWide Standard Seismograph Network (WWSSN) longperiod seismometer.
Parameters:  type  The data type: 0 (displacement), 1 (velocity) and 2 (acceleration) 

Analog to the WWSSN_LP, the simulation filter of the shortperiod seismometer of the WWSSN.
Parameters:  type  The data type: 0 (displacement), 1 (velocity) and 2 (acceleration) 
