PhaseResponse (FPScript)
Calculates the phase response from the filter coefficients.
Syntax
PhaseResponse(FilterCoefficients, [ Length = 1024 ], [ SamplingRate = 1 ] [ , Unwrapped = TRUE ])
The syntax of the PhaseResponse function consists of the following parts:
Part |
Description |
|---|---|
FilterCoefficients |
The filter coefficients for which the phase response is calculated. Permitted data structures are data series und list. All numeric data types are permitted, except calendar time und time span. |
Length |
Specifies the data length of the phase response. Permitted data structures are scalar value. Supported data types are 16-bit integer und 32-bit integer. The value must be greater than 0. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. If this argument is omitted, it will be set to the default value 1024. |
SamplingRate |
If you specify the sampling rate of the time signals for which you are using the filter, then the X component is scaled in such a way that it represents the physical frequencies. If you omit the argument, the phase response for normalized frequencies will be calculated in a range from 0 to 0.5. Permitted data structures are scalar value. All real data types are permitted. The value must be greater than 0. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. If this argument is omitted, it will be set to the default value 1. |
Unwrapped |
Specifies whether the phase response will be unwrapped. TRUE stands for phase unwrapping. Permitted data structures are scalar value. Supported data types are Boolean value. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. If this argument is omitted, it will be set to the default value TRUE. |
Remarks
The result has the unit °.
The result is a signal and the data type is always a real or complex 64-bit floating point value. The X component contains the frequencies from 0 to half of the sampling frequency.
The FilterCoefficients argument is either a list with the numerator and denominator coefficients (IIR) or a data series with the numerator coefficients (FIR) of a filter.
Available in
Option Digital Filters
Examples
PhaseResponse(IIRFilter(FILTER_BUTTERWORTH, FILTER_LOWPASS, 5, 0.1, 0.1, 0.1, FILTER_DELTA))
Calculates the phase response from the coefficients of a Butterworth low pass filter of the 5th order with the normalized cut-off frequency of 0.1. The phase response is unwrapped automatically.
PhaseResponse(IIRFilter(FILTER_ELLIPTIC, FILTER_LOWPASS, 5, 200 Hz, 0.1, 0.1, FILTER_DELTA, FILTER_COEFFICIENTS, 1 1kHz), 2048, 1000 Hz, FALSE)
Calculates the phase response of the length 2048 from the coefficients of a Cauer low pass filter of the 5th order with the cut-off frequency 200 Hz at a sampling frequency of 1000 Hz. The phase response is not unwrapped.
See Also
FIR Filter Analysis Object (Equiripple Method)