# AnalyzedResult property

Class: rfckt.mixer
Package: rfckt

Computed S-parameters, noise figure, OIP3, and group delay values

## Values

`rfdata.data` object

## Description

Handle to an `rfdata.data` object that contains the S-parameters, noise figure, OIP3, and group delay values computed over the specified frequency range using the `analyze` method. The default is a 1-by-1 `rfdata.data` object that contains the S-parameters, noise figure, OIP3, and group delay values that result from analyzing the values stored in the `default.amp` file at the frequencies stored in this file.

The `analyze` method computes the `AnalyzedResult` property using the data stored in the `rfckt.mixer` object properties as follows:

• The `analyze` method uses the data stored in the `'NoiseData'` property of the `rfckt.mixer` object to calculate the noise figure.

• The `analyze` method uses the data stored in the `'PhaseNoiseLevel'` property of the `rfckt.mixer` object to calculate phase noise. The `analyze` method first generates additive white Gaussian noise (AWGN) and filters the noise with a digital FIR filter. It then adds the resulting noise to the angle component of the input signal.

The method computes the digital filter by:

1. Interpolating the specified phase noise amplitude to determine the phase noise values at the modeling frequencies.

2. Taking the IFFT of the resulting phase noise spectrum to get the coefficients of the FIR filter.

• The `analyze` method uses the data stored in the `'NonlinearData'` property of the `rfckt.mixer` object to calculate OIP3.

If power data exists in the `'NonlinearData'` property, the block extracts the AM/AM and AM/PM nonlinearities from the power data.

If the `'NonlinearData'` property contains only IP3 data, the method computes and adds the nonlinearity by:

1. Using the third-order input intercept point value in dBm to compute the factor, f, that scales the input signal before the mixer object applies the nonlinearity:

${F}_{AM/AM}\left(u\right)=u-\frac{{u}^{3}}{3}$

2. Computing the scaled input signal by multiplying the mixer input signal by f.

3. Limiting the scaled input signal to a maximum value of 1.

4. Applying an AM/AM conversion to the mixer gain, according to the following cubic polynomial equation:

${F}_{AM/AM}\left(u\right)=u-\frac{{u}^{3}}{3}$

where u is the magnitude of the scaled input signal, which is a unitless normalized input voltage.

• The `analyze` method uses the data stored in the `'NetworkData'` property of the `rfckt.mixer` object to calculate the group delay values of the mixer at the frequencies specified in `freq`, as described in the `analyze` reference page.

• The `analyze` method uses the data stored in the `'NetworkData'` property of the `rfckt.mixer` object to calculate the S-parameter values of the mixer at the frequencies specified in `freq`. If the `'NetworkData'` property contains network Y- or Z-parameters, the `analyze` method first converts the parameters to S-parameters. Using the interpolation method you specify with the `'IntpType'` property, the `analyze` method interpolates the S-parameter values to determine their values at the specified frequencies.

Specifically, the `analyze` method orders the S-parameters according to the ascending order of their frequencies, fn. It then interpolates the S-parameters, using the MATLAB® `interp1` function. For example, the curve in the following diagram illustrates the result of interpolating the S11 parameters at five different frequencies.

For more information, see "One-Dimensional Interpolation" and the `interp1` reference page in the MATLAB documentation.

As shown in the preceding diagram, the `analyze` method uses the parameter values at fmin, the minimum input frequency, for all frequencies smaller than fmin. It uses the parameters values at fmax, the maximum input frequency, for all frequencies greater than fmax. In both cases, the results may not be accurate, so you need to specify network parameter values over a range of frequencies that is wide enough to account for the mixer behavior.

RF Toolbox™ software computes the reflected wave at the mixer input (b1) and at the mixer output (b2) from the interpolated S-parameters as

$\left[\begin{array}{c}{b}_{1}\left({f}_{in}\right)\\ {b}_{2}\left({f}_{out}\right)\end{array}\right]=\left[\begin{array}{cc}{S}_{11}& {S}_{12}\\ {S}_{21}& {S}_{22}\end{array}\right]\left[\begin{array}{c}{a}_{1}\left({f}_{in}\right)\\ {a}_{2}\left({f}_{out}\right)\end{array}\right]$

where

• fin and fout are the mixer input and output frequencies, respectively.

• a1 and a2 are the incident waves at the mixer input and output, respectively.

The interpolated S21 parameter values describe the conversion gain as a function of frequency, referred to the mixer input frequency.

## Examples

```mix1 = rfckt.mixer; mix1.AnalyzedResult ans = Name: 'Data object' Freq: [191x1 double] S_Parameters: [2x2x191 double] GroupDelay: [191x1 double] NF: [191x1 double] OIP3: [191x1 double] Z0: 50 ZS: 50 ZL: 50 IntpType: 'Linear'```