# :FUNCtion:PARameters:FFT:DISPlay

FFT Parameters Commands

- :FUNCtion:PARameters:FFT:AIMPedance
- :FUNCtion:PARameters:FFT:DETector:COUNt
- :FUNCtion:PARameters:FFT:DETector:TYPE
- :FUNCtion:PARameters:FFT:DISPlay
- :FUNCtion:PARameters:FFT:NFRequency
- :FUNCtion:PARameters:FFT:PEAK:ASCii:FDATa?
- :FUNCtion:PARameters:FFT:PEAK:ASCii:MDATa?
- :FUNCtion:PARameters:FFT:PEAK:COUNt
- :FUNCtion:PARameters:FFT:PEAK:DOUBle:FDATa?
- :FUNCtion:PARameters:FFT:PEAK:DOUBle:MDATa?
- :FUNCtion:PARameters:FFT:PEAK:ENABle
- :FUNCtion:PARameters:FFT:PEAK:LEVel
- :FUNCtion:PARameters:FFT:PEAK:SORT
- :FUNCtion:PARameters:FFT:PREFerence
- :FUNCtion:PARameters:FFT:PREFerence:TORigin
- :FUNCtion:PARameters:FFT:RBANdwidth?
- :FUNCtion:PARameters:FFT:RIMPedance
- :FUNCtion:PARameters:FFT:TFACtor
- :FUNCtion:PARameters:FFT:WINDow

Specifies the output format of an FFT operator (`:FUNCtion:FOPerator`) to be one of the following types:

- `DBM` — dBm
- `DBV` — dBV
- `DBMV` — dBmV
- `DB` — dB (Normalized)
- `DBPHz` — dBm/Hz (NSD). For Noise Spectral Density (NSD) measurements where a constant will be subtracted from the FFT function.
- `MAGNitude` — Linear Magnitude
- `PHASe` — Phase
- `UPHase` — Unwrapped Phase
- `GDELay` — Group Delay

When phase (`PHASe`), unwrapped phase (`UPHase`), or group delay (`GDELay`) is selected, use the `:FUNCtion:PARameters:FFT:PREFerence` command to set the FFT phase reference to left, center, or manual. If you select manual, use the `:FUNCtion:PARameters:FFT:PREFerence:TORigin` command to enter the FFT origin in seconds.

If the input is an optical signal and dBV (Electrical) is selected, use the `:FUNCtion:PARameters:FFT:TFACtor` command to enter the voltage conversion factor (V/W).

To ensure that enough data is available to construct a useful FFT, set Infiniium's timebase scale equal to the waveform's period. This will display 10 waveform cycles. For example, for a 5 GHz (200 ps) reference clock, enter a scale setting of 200 ps/division.

## Content Windows

The FFT waveform is automatically displayed in the appropriate type of content window, which is listed in the following table and displayed in the above picture. For the `DBHertz`, `DHERtz`, and `SHERtz` arguments, you can optionally move the waveform to an additional content window of the same type using the `:FUNCtion:CWINdow` command. For example,

    :FUNCtion1:FOPerator FFT  // Create an FFT function.
    :FUNCtion1:OPERand1 CHAN1_1  // Assign input waveform.
    :FUNCtion1:PARameters:FFT:DISPlay GDELay  // Select output waveform type. Waveform is automatically assigned to content window GDELay1.
    :FUNCtion1:CWINdow GDELay2  // Display content window GDELay2 (Delay 2) and re-assign output waveform from GDELay1 to GDELay2.

Command Arguments and Resulting Waveform Content Window
Argument | Equivalent GUI Selection | Displayed Content Window | Number of Available Windows | Scale Units
--- | --- | --- | --- | ---
Via Front Panel | Programmatically
DBM | dBm | Decibels (Hz) | 1 | 4 | Y-Axis: dBm (logarithmic scale) X-Axis: Hertz
DBV | dBV | Y-Axis: dBV (logarithmic scale) X-Axis: Hertz
DBMV | dBmV | Y-Axis: dBmV (logarithmic scale) X-Axis: Hertz
DB | dB (Normalized) | Y-Axis: dB (logarithmic scale) X-Axis: Hertz
DBPHz | dBm/Hz (NSD) | Y-Axis: dBm/Hz (logarithmic scale) X-Axis: Hertz
MAGNitude | Linear Magnitude | Waveform | 1 | 4 | Y-Axis: Volts or Watts (linear scale) X-Axis: Hertz
PHASe | Phase | Degrees (Hz) | 1 | 4 | Y-Axis: phase (°) X-Axis: Hertz
UPHASe | Unwrapped Phase
GDELay | Group Delay | Seconds (Hz) | 1 | 4 | Y-Axis: seconds X-Axis: Hertz

## Example Command Sequence

    :FUNCtion2:FOPerator FFT
    :FUNCtion2:PARameters:FFT:DISPlay DBM
    :FUNCtion2:PARameters:FFT:WINDow HANNing
    :FUNCtion2:COLor TCOLor4
    :FUNCtion2:DISPlay ON
    *OPC?
    …  //  Your code to synchronize execution timing.