SFILTER_NONREC (in, out, n, flow, fhigh, wiggles, nterms, [status])
in REAL*4 On entry, a one-dimensional array IN containing the data to be filtered. On exit, in is unchanged. out REAL*4 On entry, a one-dimensional array OUT containing the filtered data. The IN and OUT arrays can be the same array. On exit, out is overwritten and contains the filtered data. n INTEGER*4 On entry, the number of values to be filtered; n > 2 and n<SP>>=<SP>2(nterms+1). On exit, n is unchanged. flow REAL*4 On entry, the lower frequency of the filter, given as a fraction of the Nyquist sampling frequency 1/(2delta_t); 0.0<SP><=<SP>flow<SP><=<SP>1.0. On exit, flow is unchanged. fhigh REAL*4 On entry, the upper frequency of the filter, given as a fraction of the Nyquist sampling frequency 1/(2delta_t); 0.0<SP><=<SP>fhigh<SP><=<SP>1.0. On exit, fhigh is unchanged. wiggles REAL*4 On entry, a number in -dB units which is proportional to the oscillation from the Gibbs phenomenon; 0.0<SP><=<SP>wiggles<SP><=<SP>500.0. On exit, wiggles is unchanged. nterms INTEGER*4 On entry, the order of the filter, that is, the number of filter coefficients in the filter equation; 2<SP><=<SP>nterms<SP><=<SP>500 and n<SP>>=<SP>2(nterms+1). On exit, nterms is unchanged. status INTEGER*4 On entry, an optional variable with an unspecified value. On exit, status is overwritten. When the subroutine is called, status is defined and its integer value describes the status of the operation. The following table shows the status function names, their associated integer values, and the status description associated with each integer. Status Function Value Description Returned DXML_SUCCESS() 0 Succesful execution DXML_MAND_ARG() 1 Mandatory argument is missing DXML_ILL_WIGGLES() 5 wiggles is out of range DXML_ILL_FLOW() 6 flow is equal to fhigh DXML_ILL_F_RANGE() 7 flow or fhigh is out of range DXML_ILL_N_RANGE() 8 n is out of range DXML_ILL_N_NONREC() 9 n is less than (2*nterms+1) DXML_ILL_NTERMS() 10 nterms is out of range
The SFILTER_NONREC subroutine performs nonrecursive filtering in either lowpass, highpass, bandpass, or bandstop (notch) mode. See the CXML Reference Guide for information on controlling the filter type with the flow and fhigh arguments.