Can I specify a frequency-dependent IP3 parameter in the RF Blockset?

I am using the s-Parameters Mixer in the RF Blockset 2.0 (R2007a) and would like to enter the IP3 parameter as a function of frequency. The block mask does not allow me to enter a vector in this field.

Answer 1

[MathWorks Support Team]

This enhancement has been incorporated in Release 2008b (R2008b). For previous product releases, read below for any possible workarounds:

To work around this issue, use the General Circuit Element block from the Black Box Elements library. Use the following command line functionality to define an RFCKT object called mixer that specifies the mixer behavior and then set the 'RFCKT object' parameter of the General Circuit Element block to the MATLAB variable mixer:

% mixer for the mask parameter ‘RFCKT object’ of the General Circuit Element block % is an RFCKT.MIXER object and should be created in MATLAB workspace:

mixer = rfckt.mixer;

% Create data objects for frequency-dependent S-parameters, spot noise and IP3: 

freq = [1e9 1.4e9];     % two frequencies

sparams(:,:,1) = [-0.7247 - 0.4813i        0;           -0.6857 + 1.7827i  -0.0741 - 0.3216i];

sparams(:,:,2) = [-0.7318 - 0.4715i   0.0014 + 0.0005i; -0.6560 + 1.7980i  -0.0761 - 0.3190i];

sparamsData = rfdata.network('Type', 'S', 'Freq', freq, 'Data', sparams);

freq = [1e9 1.4e9];                       % two frequencies

fmin = [12.08 13.40];                     % Minimum noise figure in dB

gopt = [0.2484-1.2102j 1.0999-0.9295j];   

% "gopt" is a source reflection coefficient to realize minimum noise figure

rn = [0.26 0.45];                         % Equivalent normalized noise resistance

noiseData = rfdata.noise('Freq', freq, 'FMIN', fmin, 'GAMMAOPT', gopt, 'RN', rn);

freq = [1e9 1.4e9];     % two frequencies

ip3 = [0.001 0.05];     % IP3 in Watts at two frequencies

ip3Data = rfdata.ip3('Type', 'IIP3', 'Freq', freq, 'Data', ip3);

% Set mixer’s three properties: NetworkData, NoiseData and NonlinearData with

% three data objects:

mixer.NetworkData = sparamsData

mixer.NoiseData = noiseData

mixer.NonlinearData = ip3Data