DFD Dolph-Chebyshev Order Estimation VI

Digital Filter Design VIs and Functions

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Owning Palette: Advanced FIR Filter Design VIs

Installed With: Digital Filter Design Toolkit

Estimates the order of a finite impulse response (FIR) filter that you designed by using the Dolph-Chebyshev Window method.

Place on the block diagram

Find on the Functions palette

filter type specifies the type of filter that this VI creates.

0	Lowpass (default)
1	Highpass
2	Bandpass
3	Bandstop

freq specs specifies the band edge frequencies of the filter.

	fpass 1 specifies the first passband edge frequency in hertz.
	fstop 1 specifies the first stopband edge frequency in hertz.
	fpass 2 specifies the second passband edge frequency in hertz. This VI ignores this input for lowpass and highpass filters.
	fstop 2 specifies the second stopband edge frequency in hertz. This VI ignores this input for lowpass and highpass filters.

ripple specs specifies the ripple level in the passband and stopband of the filter.

	passband specifies the ripple level in the passband. The default is 0.1.
	stopband specifies the ripple level in the stopband. The default is 60.
	dB/linear? specifies whether this VI applies a decibel scale or a linear scale to the ripple levels. If the value is TRUE, this VI applies a decibel scale to the ripple level. If the value is FALSE, this VI applies a linear scale to the ripple level. The default is TRUE.

order option specifies filter order requirements. The default is MinEven, which yields the minimum even order for the filter to meet the specifications you set.

0	MinNum
1	MinEven (default)
2	MinOdd

error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.

	status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
	code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
	source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.

fs specifies the sampling frequency in hertz. The value must be greater than zero. The default is 1, which is the normalized sampling frequency.

estimated order returns the minimum order value that the filter requires to meet the specifications you set.

high cutoff freq returns the high cutoff frequency. The cutoff frequency is the frequency with one-half magnitude response.

low cutoff freq returns the low cutoff frequency. The cutoff frequency is the frequency with one-half magnitude response.

error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
	code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
	source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

ripple ratio returns the side-lobe attenuation provided by the Dolph-Chebyshev Window in decibels.

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