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Last Modified: March 30, 2017

Computes the averaged FFT spectrum of a time-domain signal and returns the FFT results as magnitude and phase.

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

Time-domain window to apply to the signal.

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. |

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 an Exponential window. |

**Default: **Hanning

A Boolean that specifies whether the node restarts the selected averaging process.

True | Restarts the averaging process. |

False | Does not restart the averaging process. |

When you call this node for the first time, the averaging process restarts automatically. A typical case when you restart averaging is when a major input change occurs in the middle of the averaging process.

**Default: **False

Input signal.

This input accepts the following data types:

- Waveform
- Waveform in complex double-precision, floating-point numbers
- 1D array of waveforms
- 1D array of waveforms in complex double-precision, floating-point numbers
- 1D array of double-precision, floating-point numbers
- 1D array of complex double-precision, floating-point numbers
- 2D array of double-precision, floating-point numbers
- 2D array of complex double-precision, floating-point numbers

Settings that define how this node returns results.

Settings that define how this node computes the averaging.

The mode this node uses to compute the averaging.

Name | Description |
---|---|

No averaging | Does not use averaging. |

Vector averaging | Uses vector averaging. |

RMS averaging | Uses RMS averaging. |

Peak hold | Uses peak hold averaging. |

**Default: **No averaging

Weighting mode for RMS and vector averaging.

Name | Description |
---|---|

Linear | Uses linear weighting. |

Exponential | Uses exponential weighting. |

**Default: **Exponential

Number of averages to use for RMS and vector averaging.

If **weighting mode** is Exponential, the averaging process is continuous. If **weighting mode** is Linear, the averaging process stops after this node computes the specified number of averages.

**Default: **10

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an **error in** input and an **error out** output so that the node can respond to and communicate errors that occur while code is running. The value of **error in** specifies whether an error occurred before the node runs. Most nodes respond to values of **error in** in a standard, predictable way.

**Default: **No error

Sample period of the time-domain signal in seconds.

Set this input to 1/*fs*, where *fs* is the sampling frequency of the time-domain signal.

This input is available only if you wire one of the following data types to **signal**:

- 1D array of double-precision, floating-point numbers
- 1D array of complex double-precision, floating-point numbers
- 2D array of double-precision, floating-point numbers
- 2D array of complex double-precision, floating-point numbers

**Default: **1

Magnitude of the averaged FFT spectrum of the input signal.

This output can return a cluster or a 1D array of clusters.

Start frequency, in Hz, of the spectrum.

Frequency resolution, in Hz, of the spectrum.

Magnitude of the averaged FFT spectrum.

If the input signal is in volts (V), this output has units of volts-rms (V_{rms}). If the input signal is not in volts, this output has units of the input signal unit-rms. If the results are in decibels and the input signal is in volts, this output has units of dBV.

Phase of the averaged FFT spectrum of the input signal.

This output can return a cluster or a 1D array of clusters.

Start frequency, in Hz, of the spectrum.

Frequency resolution, in Hz, of the spectrum.

Phase, in radians, of the averaged FFT spectrum.

A Boolean that indicates whether the number of averages this node completed is greater than or equal to the specified number of averages.

True | The number of averages this node completed is greater than or equal to the specified number of averages. |

False | The number of averages this node completed is less than the specified number of averages. |

** averaging done** is True if **averaging mode** is No averaging.

Number of averages this node completed.

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

**error in** input and an **error out** output so that the node can respond to and communicate errors that occur while code is running. The value of **error in** specifies whether an error occurred before the node runs. Most nodes respond to values of **error in** in a standard, predictable way.

This node completes the following steps to compute **magnitude** and **phase**:

**Where This Node Can Run: **

Desktop OS: Windows

FPGA: This product does not support FPGA devices