In this example, with gradually increasing input power, findpeaks filter MinPeakProminence is tricky because with constant input I visually chose it to be 40 but once input power level seep is in place, for shorter peaks such threshold has to be smaller otherwise findpeaks misses values needed to be taken into account.

​

​

Spectrum peaks capture - input ramp

%% SYSTEM

a_coeff=[.12 -.4 12 .5]

Z0=1

%% TIME FRAME

f=[2.1 2.3]*1e9          % [Hz] input carriers

Fs = 10*f(2);              % sampling rate

Nspf=4096              % samples per frame

%% INPUT CARRIERS

Sineobject1 = dsp.SineWave

Sineobject1.SamplesPerFrame=2*1024

Sineobject1.PhaseOffset=0

Sineobject1.SampleRate=Fs

Sineobject1.Frequency=f(1) 

Sineobject2 = dsp.SineWave

Sineobject2.SamplesPerFrame=2*1024

Sineobject2.PhaseOffset=0

Sineobject2.SampleRate=Fs

Sineobject2.Frequency=f(2)  

%% TEST INSTRUMENT

SA3 = dsp.SpectrumAnalyzer

SA3.Name='fig.16 : Spectrum Analyser 03'

SA3.SampleRate=Fs

SA3.Method='Filter bank'

SA3.SpectrumType='Power'

SA3.PlotAsTwoSidedSpectrum=false

SA3.ChannelNames={'S_in(f)'}

SA3.YLimits=[-80 110]

SA3.ShowLegend=true

SA3.CursorMeasurements.Enable = true;

SA3.ChannelMeasurements.Enable = true;

SA3.PeakFinder.Enable = true;

SA3.PeakFinder.NumPeaks=14

SA3.PeakFinder.MinDistance=8 % distance in number of samples SA4.PeakFinder.Threshold=    % min height difference of peak with

                                                    % neighbouring peaks, don't set in case neighbouring peaks have similar levels.

SA3.PeakFinder.MinHeight= -40             % [dBm] squelch, do not detect below this level

SA3.DistortionMeasurements.Enable = true;

N_iter=1e3                                               % amount of time to repeat sweep with same input power

%% RAMP

N0_dBm=-60                                           % visual inspection, noise floor fairly flat at -60dBmW/Hz

                                                              % change start stop input power values to adjust test window

Pin_start=10^((N0_dBm-30)/10)                             % [W] start ramp

Pin_stop=1e2                                                                % [W] stop ramp

Pin_start_dBm=10*log10(Pin_start)+30                  % [dBmW] start ramp

Pin_stop_dBm=10*log10(Pin_stop)+30                   % stop ramp

N_ramp=30                                                                   % choose amount of levels, ramp resolution

ramp1_dBm=linspace(Pin_start_dBm,Pin_stop_dBm,N_ramp)   % input power ramp [dBmW]

ramp1_W=10.^((ramp1_dBm-30)/10)                                           % input power ramp [W]

ramp1_V_Z0=(ramp1_W*2*Z0).^.5

%% DAQ LOOP 3

data_measurement = [];

% data_f_trace = [];

for k=1:1:numel(ramp1_V_Z0)

Sineobject1.Amplitude=ramp1_V_Z0(k)

Sineobject2.Amplitude=ramp1_V_Z0(k)

for Iter = 1:N_iter

    st1 = Sineobject1();

    st2 = Sineobject2();

    s_in2 = a_coeff(1)*ones(numel(st1),1)+...

            a_coeff(2)*(st1 + st2)+...

            a_coeff(3)*(st1.*st1+st2.*st2+2*st1.*st2)+...

            a_coeff(4)*(st1.*st1.*st1+st2.*st2.*st2+...

            3*st1.*st1.*st2+3*st2.*st2.*st1)+...

            0.001*randn(numel(st1),1);

    SA3(s_in2);

    if SA3.isNewDataReady

        data_measurement = [data_measurement;getMeasurementsData(SA3)];

        % data_f_trace = [data_f_trace;getSpectrumData(SA4)];

    end

end

end

No need to elaborate on the fact that not many RF systems can accurately generate carriers from -60dBm(W) up to 96dBm(W) = 4MW RF power.

There are critical factors not considered in chapter 10 to take into account like cooling, load capacity to stand delivered power, for how long has the load to stand peak power .. and the critical module that supports them all: power supply;

No RF system can deliver more power than a fraction of the power made available by its power supply. Safety measures have to be implemented to avoid power supply overload.

First I am sampling to understand data format: