MEIFilterType

Definition

typedef enum {
    MEIFilterTypeUNITY_GAIN, 
        /* B0 = 1    B1=B2=A1=A2 = 0  
        (effectively acting as no filter) */
    MEIFilterTypeSINGLE_ORDER,
    MEIFilterTypeLOW_PASS,
    MEIFilterTypeHIGH_PASS,
    MEIFilterTypeNOTCH,
    MEIFilterTypeRESONATOR,
    MEIFilterTypeLEAD_LAG,
    MEIFilterTypeZERO_GAIN,	
        /* b0=b1=b2=a1=a2 = 0  
        (this does act as a filter.... zeroing the output) */
    MEIFilterTypeBIQUAD,
        /* Only valid for setting.  
        Reading will not return these types */
    MEIFilterTypeDIGITAL_BIQUAD,
    MEIFilterTypePOLES_ZEROS,
    MEIFilterTypeDIGITAL_POLES_ZEROS,
    MEIFilterTypeUNKNOWN,	
        /* algorithm couldn't figure out what 
        this filter was from the coeffs! */ 
} MEIFilterType;

Description

NOTE: The MPI will attempt to return analog & digital biquad and pole/zero information from meiFilterPostfilterGet(...) and meiFilterPostfilterSectionGet(...). However, the filter types MEIFilterTypeDIGITAL_BIQUAD, MEIFilterTypePOLES_ZEROS, and MEIFilterTypeDIGITAL_POLES_ZEROS are never returned by get() calls -- they are used only for setting postfilters. MEIFilterTypeBIQUAD will only be returned by meiFilterPostfilterGet(...) and meiFilterPostfilterSectionGet(...) if the analog coefficients can be calculated (there is no division by 0) and the section cannot be identified as one of the other analog filter types.

MEIFilterTypeUNITY_GAIN	A unity gain filter. This effectively performs no filtering.
MEIFilterTypeSINGLE_ORDER	A single order filter
MEIFilterTypeLOW_PASS	A low pass filter
MEIFilterType_HIGH_PASS	A high pass filter.
MEIFilterTypeNOTCH	A notch filter
MEIFilterTypeRESONATOR	A resonator filter.
MEIFilterTypeLEAD_LAG	A lead or lag filter.
MEIFilterTypeZERO_GAIN	Zeros the output of a filter.
MEIFilterTypeBIQUAD	An analog biquad filter. When reading postfilter data, this type means that the postfilter section could not be identified as a standard filter type.
MEIFilterTypeDIGITAL_BIQUAD	A digital biquad filter. This is only used for setting postfilter sections.
MEIFilterTypePOLES_ZERO	Analog poles and zeros filter (maximum of two poles and zeros) with unity zero-frequency amplitude. This is only used for setting postfilter sections.
MEIFilterTypeDIGITAL_POLES_ZEROS	Digital poles and zeros filter (maximum of two poles and zeros) with unity zero-frequency amplitude. This is only used for setting postfilter sections.
MEIFilterTypeUNKNOWN	Returned by meiFilterPostfilterGet(...) and meiFilterPostfilterSectionGet(...) if analog coefficients cannot be found. only digital data will be available.