Phase Noise Profile from Time Domain Signal

Open Live Script

Load the time domain signal represented by the time and signal value vectors.

load time_1.mat;
load signal_1.mat;

Set the resolution bandwidth of the spectrum analysis to 75 kHz. The frequency offset points are 100 kHz, 300 kHz, 500kHz, 1 MHz, 3 MHz, and 10 MHz. The target phase noise profile corresponding to these frequency offset points is:

  • -130 dBc/Hz at 100 kHz

  • -140 dBc/Hz at 300 kHz

  • -135 dBc/Hz at 500 kHz

  • -130 dBc/Hz at 1 MHz

  • -140 dBc/Hz at 3 MHz

  • -155 dBc/Hz at 10 MHz

rbw = 75e3;
FrOffset = [100e3 300e3 500e3 1e6 3e6 10e6];
PNTarget = [-130 -140 -135 -130 -140 -155];

Use the phaseNoiseMeasure function to measure and plot the phase noise profile.

[PNMeasure] = phaseNoiseMeasure(t,x,rbw,FrOffset,'on','Phase noise',PNTarget,'Type','Time','Histogram','on')

Figure contains an axes object. The axes object with title Histogram of Signal's Half-Period Data contains an object of type histogram.

Figure Phase Noise Analysis (Phase noise) contains an axes object. The axes object with title Phase Noise No. of Averages = 3 Center Frequency = 70.0001 MHz, xlabel Frequency offset (Hz), ylabel Phase noise (dBc/Hz) contains 2 objects of type line. These objects represent Measured, Target.

PNMeasure = 6×1

 -116.0947
 -138.8840
 -135.6692
 -133.4506
 -135.8644
 -104.3224