Simple custom filter settingsThe cu

Simple custom filter settingsThe custom filter incorporates several advanced facilities for special purpose analysis. If a filter like the fixed filters is required, but for a different wavelength range, the filter parameters should be set as follows: Filter type: Bandpass Order: 3 Minimum wavelength: set to the desired minimum wavelength Maximum wavelength: set to the desired maximum wavelength Zero delay filter: leave unchecked Invert displacement: leave uncheckedTo implement the custom filter when all the parameters have been checked and set, click the OK button. Otherwise click Cancel to remove the Custom Filter panel without changing the currently-set filter.Advanced custom filter settingsThe custom filter implements a band-pass, low-pass or high-pass filter which is a discrete-time Butterworth-equivalent design. For special purpose analysis, the filter parameters can be set as follows: Filter type: Set to Band-pass, Long-pass or Short-pass.If set to Bandpass, a bandpass filter between the minimum and maximum wavelengths specified will be implemented. If set to Longpass, a lowpass filter that passes wavelengths longer than the minimum specified wavelength will be implemented.If set to Shortpass, a highpass filter that passes wavelengths shorter than the maximum specified wavelength will be implemented. Order: Specifies the order of the filter, which determines the ‘slope’ of the filter edges. Any number from 1 (slope of 6dB per octave) to 10 (60dB per octave) © 2019 RailMeasurement Ltd RailMeasurement CAT User Guide version 511 April 2019 Page 18can be specified. The fixed filters in the CAT software – and the third-octave filters- have an order of 3.