phaseNoiseMeasure

Measure and plot phase noise profile of time or frequency-domain signal

Since R2020a

Syntax

PNMeasure = phaseNoiseMeasure(Xin,Yin,RBW,FrOffset,PlotOption,tag,Name,Value)

PNMeasure = phaseNoiseMeasure(___,PNTarget,Name,Value)

[PNMeasure,GenFrOffset,GenPN] = phaseNoiseMeasure(___)

Description

PNMeasure = phaseNoiseMeasure(Xin,Yin,RBW,FrOffset,PlotOption,tag,Name,Value) measures the single-sideband phase noise levels of either a time or frequency-domain signal at the specified frequency offset points. The function also plots phase noise profile at the specified frequency offset points when you specify the PlotOption argument as 'on'. If you specify the Name-Value pair argument, enclose each argument name in quotes. Unspecified arguments take default values.

PNMeasure = phaseNoiseMeasure(___,PNTarget,Name,Value) in addition to the input arguments in the previous syntax compares phase noise levels at the specified frequency offsets to a target phase noise profile. Set the PlotOption argument to 'on' to plot and compare the measured phase noise profile to the target profile.

[PNMeasure,GenFrOffset,GenPN] = phaseNoiseMeasure(___) additionally returns the phase noise waveform data represented by the frequency offset vector and the corresponding phase noise vector.

Examples

Phase Noise Profile from Frequency and Power Vectors

Load the power spectrum data (frequency and power vectors) of the signal obtained from spectrum analysis.

load frequency.mat;
load corresponding_power.mat;

Set the resolution bandwidth of the spectrum analysis to 25 kHz. The frequency offset points are 30 kHz, 100 kHz, 1 MHz, 3 MHz, and 10 MHz. The target phase noise profile corresponding to these frequency offset points is:

• -56 dBc/Hz at 30 kHz

• -106 dBc/Hz at 100 kHz

• -132 dBc/Hz at 1 MHz

• -143 dBc/Hz at 3 MHz

• -152 dBc/Hz at 10 MHz

rbw = 25e3;
FrOffset = [30e3 100e3 1e6 3e6 10e6];
PNTarget = [-56 -106 -132 -143 -152];

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

PNMeasure = phaseNoiseMeasure(f1,p1,rbw,FrOffset,'on','Phase noise', PNTarget)

PNMeasure = 5×1

  -70.8795
 -106.2594
 -136.6468
 -147.3779
 -157.0967

Phase Noise Profile from Time Domain Signal

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')

PNMeasure = 6×1

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

Input Arguments

Xin — Time or frequency vector

positive real vector

Time or frequency vector, specified as a positive real vector. If you specify a time-domain signal or 'Type' name-value pair as 'Time', Xin is a time vector in seconds. If you specify a frequency-domain signal or 'Type' name-value pair as 'Frequency', Xin is a frequency vector in hertz.

Data Types: double

Yin — Signal value or power vector

real vector

Signal value or power vector, specified as a real vector. If you specify a time-domain signal or 'Type' name-value pair as 'Time', Yin is a signal value vector in volts. If you specify a frequency-domain signal or 'Type' name-value pair as 'Frequency', Yin is a power vector in dBm.

Data Types: double

RBW — Resolution bandwidth used in spectrum analysis

positive real scalar

Resolution bandwidth used in the spectrum analysis, specified as a positive real scalar in hertz. RBW defines the smallest positive frequency at which the frequency components of a signal can be resolved.

Data Types: double

FrOffset — Frequency offset points to measure phase noise

positive real vector

Frequency offset points at which phase noise levels are calculated, specified as a positive real vector in hertz.

Data Types: double

PlotOption — Plot phase noise analysis results

'on' | 'off'

Plot the phase noise analysis results in a figure, specified as on or off. Set PlotOption to 'on' to view the power spectrum and phase noise profile plots. If the Name-Value pair argument 'Type' is specified as 'Time', you can only plot the phase noise profile of the time-domain signal.

Data Types: char

tag — Figure identifier

string scalar | character vector

Figure identifier, specified as a string scalar or a character vector. Tag figures to keep multiple plots open as you change the simulation parameters.

Data Types: char | string

PNTarget — Target phase noise levels

real vector

Target phase noise levels corresponding to the frequency offset points defined in FrOffset, specified as real vector in dBc/Hz. To compare PNTarget with PNMeasure, set PlotOption argument to on to view the phase noise comparison plot.

Data Types: double

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: PNMeasure = phaseNoiseMeasure(f1,p1,rbw,FrOffset,'on','Phase noise', PNTarget,'Type','Frequency','Histogram','on')

Type — Type of input signal

'Frequency' (default) | 'Time'

Type of the input signal, specified as the comma-separated consisting of 'Type' and one of the following:

• 'Frequency' if the input signal is power spectrum data.

• 'Time' if the input signal is time domain data.

Histogram — Plot histogram of half-period information for time-domain signal

'off' (default) | 'on'

Plot the histogram of the half-period information for the time-domain signal, specified as the comma-separated pair consisting of 'Histogram' and 'off' or 'on'. You can plot the histogram only when 'Type' is specified as 'Time'.

Output Arguments

PNMeasure — Measured phase noise levels

real vector

Measured single-sideband phase noise levels corresponding to frequency offset points defined in FrOffset, returned as a real vector in dBc/Hz. You can compare PNMeasure with the target phase noise levels with PNTarget defined in the function.

Data Types: double

GenFrOffset — Frequency offset points used to plot phase noise profile

vector

Frequency offset points generated by the phaseNoiseMeasure function that are used to plot the phase noise profile, returned as a vector.

Data Types: double

GenPN — Phase noise values used to plot phase noise profile

vector

Phase noise values generated by the phaseNoiseMeasure function that are used to plot the phase noise profile, returned as a vector. Each element in GenPN represents the phase noise at the corresponding frequency offset point represented in GenFrOffset.

Data Types: double

Version History

Introduced in R2020a