PhaseNoiseConfiguration

R2026b

Measure and display phase noise

Since R2025a

expand all in page

    Description

    Use the PhaseNoiseConfiguration object to measure and display phase noise by using the spectrum analyzer.

    Note

    To create and use the PhaseNoiseConfiguration object, you must have a valid Mixed-Signal Blockset™ license.

    You can measure the phase noise and plot it against the specified target phase noise profile from the spectrum analyzer toolstrip or from the command line. The spectrumAnalyzer object and the SpectrumAnalyzerBlockConfiguration object support the PhaseNoiseConfiguration object in the command line.

    To enable the phase noise measurements on the spectrum analyzer toolstrip, select the Phase Noise in the Measurements tab. To modify the phase noise measurement settings, click the Phase Noise drop-down arrow.

    Spectrum Analyzer window showing the phase noise measurements.

    Creation

    Syntax

    phasemeas = PhaseNoiseConfiguration()

    Description

    phasemeas = PhaseNoiseConfiguration() creates a phase noise measurements configuration object phasemeas. Use this configuration object with the spectrumAnalyzer and SpectrumAnalyzerBlockConfiguration objects.

    example

    Properties

    expand all

    All properties are tunable.

    Frequency offsets at which the scope measures the phase noise, specified as a numeric vector in Hz with monotonically increasing values.

    Tunable: Yes

    Scope Window Use

    On the Measurements tab, select Phase Noise, and then click the Phase Noise drop-down arrow to set Frequency Offsets (Hz) to a numeric vector.

    Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

    Option to plot the target phase noise profile, specified as a logical 1 (true) or 0 (false). When you set this property to 1 (true), the spectrum analyzer plots the target phase noise profile that you specify in the TargetPhaseNoise property.

    Tunable: Yes

    Scope Window Use

    On the Measurements tab, select Phase Noise, and then click the Phase Noise drop-down arrow to select Plot Target Phase Noise.

    Data Types: logical

    Target phase noise profile in dBc/Hz, specified as a numeric vector of the same length as the FrequencyOffset vector.

    Tunable: Yes

    Dependencies

    To enable this property, set PlotTargetPhaseNoise to true.

    Scope Window Use

    On the Measurements tab, select Phase Noise, and then click the Phase Noise drop-down arrow to select Plot Target Phase Noise and specify Target Phase Noise (dBc/Hz) to a numeric vector.

    Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

    Option to label the measured phase noise on the plot, specified as a logical 1 (true) or 0 (false). When you set this property to 1 (true), the spectrum analyzer labels the measured phase noise values on the plot as SN1, SN2, and so on.

    Tunable: Yes

    Scope Window Use

    On the Measurements tab, select Phase Noise, and then click the Phase Noise drop-down arrow to select Label Phase Noise.

    Data Types: logical

    Option to enable the phase noise measurements, specified as a logical 1 (true) or 0 (false). When you set this property to 1 (true), the spectrum analyzer measures and plots the phase noise.

    Tunable: Yes

    Scope Window Use

    To enable the phase noise measurements, select Phase Noise on the Measurements tab.

    Data Types: logical

    Examples

    collapse all

    This example uses:

    Open Live Script

    Measure the phase noise of a noisy sinusoidal signal using the PhaseNoise property of the spectrumAnalyzer object.

    Initialization

    Construct a spectrumAnalyzer object. Set the spectrum estimation method to "welch", averaging method to "exponential", forgetting factor to 0.9, RBW to 25000, and frequency offset to 2700 MHz.

    Fs = 40e6;
rbw = 25e3;
Offset = 2.7e9;
sa = spectrumAnalyzer(SampleRate=Fs,...
    RBWSource="property",...
    RBW=rbw,...
    Method="welch",...
    AveragingMethod="exponential",...
    ForgettingFactor=0.9,...
    FrequencyOffset=Offset,...
    Window="hann",...
    ShowLegend=true,...
    YLimits=[-220 50]);

    Enable Measurements Data

    Enable the phase noise measurements and set the corresponding phase noise properties:

    • FrequencyOffset to [30000 100000 1000000 3000000 10000000 19000000]

    • TargetPhaseNoise to [-56 -106 -132 -143 -152 -160]

    • LabelPhaseNoise to true 

    sa.PhaseNoise.Enabled=true;
sa.PhaseNoise.FrequencyOffset=[30000 100000 1000000 3000000 10000000 19000000];
sa.PhaseNoise.PlotTargetPhaseNoise=true;
sa.PhaseNoise.TargetPhaseNoise=[-56 -106 -132 -143 -152 -160];
sa.PhaseNoise.LabelPhaseNoise=true;

    Plot Phase Noise Measurements

    Stream in a noisy sinusoidal signal with 2400 samples in each frame, and view its spectrum using the spectrum analyzer. The scope shows the phase noise of the signal in the phase noise axis and the corresponding measurements in the phase noise panel at the bottom. The scope plots the target phase noise profile in a red dashed line.

    Use the getMeasurementsData function to obtain the phase noise measurements programmatically. The values shown in the measurement panels match the values shown in data.

    data = [];
frameSize = 2400;
sw = dsp.SineWave(SampleRate=Fs,SamplesPerFrame=frameSize);
for idx = 1:10
    noise = 1e-8.*randn(frameSize,1);
    sa(sw() + noise);
    if sa.isNewDataReady
        data = [data;getMeasurementsData(sa)];
    end
end

    Version History

    Introduced in R2025a

    expand all

    See Also

    |