Table Of Contents
Filter (Lowpass » Windowed FIR) (G Dataflow)
Filters a signal using a lowpass windowed FIR filter. Lowpass filters pass low frequencies and attenuate high frequencies.
window parameter
A value that affects the output coefficients when window type is Kaiser, Gaussian, or Dolph-Chebyshev.
If window type is any other type of window, this node ignores this input.
This input represents the following information for each type of window:
- Kaiser—Beta parameter
- Gaussian—Standard deviation
- Dolph-Chebyshev—The ratio, s, of the main lobe to the side lobe
Default: NaN—Causes this node to set beta to 0 for a Kaiser window, the standard deviation to 0.2 for a Gaussian window, and s to 60 for a Dolph-Chebyshev window
window type
Type of the smoothing window.
Smoothing windows decrease ripple in the filter passband and improve the ability of the filter to attenuate frequency components in the filter stopband.
| Name | Value | Description |
|---|---|---|
| Rectangle | 0 | Applies a rectangle window. |
| Hanning | 1 | Applies a Hanning window. |
| Hamming | 2 | Applies a Hamming window. |
| Blackman-Harris | 3 | Applies a Blackman-Harris window. |
| Exact Blackman | 4 | Applies an Exact Blackman window. |
| Blackman | 5 | Applies a Blackman window. |
| Flat Top | 6 | Applies a Flat Top window. |
| 4 Term B-Harris | 7 | Applies a 4 Term B-Harris window. |
| 7 Term B-Harris | 8 | Applies a 7 Term B-Harris window. |
| Low Sidelobe | 9 | Applies a Low Sidelobe window. |
| Blackman Nutall | 11 | Applies a Blackman Nutall window. |
| Cosine Tapered | 12 | Applies a Cosine Tapered window. |
| Triangle | 30 | Applies a Triangle window. |
| Bartlett-Hanning | 31 | Applies a Bartlett-Hanning window. |
| Bohman | 32 | Applies a Bohman window. |
| Parzen | 33 | Applies a Parzen window. |
| Welch | 34 | Applies a Welch window. |
| Kaiser | 60 | Applies a Kaiser window. |
| Dolph-Chebyshev | 61 | Applies a Dolph-Chebyshev window. |
| Gaussian | 62 | Applies a Gaussian window. |
| Force | 64 | Applies a Force window. |
| Exponential | 65 | Applies a Exponential window. |
Default: Rectangle
reset
A Boolean that specifies the initialization of the internal state of the node.
| True | Initializes the internal state to zero. |
| False | Initializes the internal state to the final state from the previous call of this node. |
This node automatically initializes the internal state to zero on the first call and runs continuously until this input is True.
Default: False
signal
cutoff frequency
Cutoff frequency of the filter.
Default: 0.125
number of taps
Number of taps in the FIR filter.
Default: 25
order
Order of the filter.
Default: 2
error in
Error conditions that occur before this node runs. The node responds to this input according to standard error behavior.
Default: No error
sampling frequency
The sampling frequency in Hz.
sampling frequency is available only if you wire a 1D or 2D array of double-precision, floating-point numbers to signal. The value must be greater than zero.
Default: 1, which is the normalized sampling frequency
filtered signal
Result of filtering the input signal.
Where This Node Can Run:
Desktop OS: Windows
FPGA: Not supported