# AnalyzedResult property

Class: rfckt.txline
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. This property is empty by default.

The `analyze` method treats the transmission line, which can be lossy or lossless, as a 2-port linear network. It computes the `AnalyzedResult` property of a stub or as a stubless line using the data stored in the `rfckt.txline` object properties as follows:

• If you model the transmission line as a stubless line, the `analyze` method first calculates the ABCD-parameters at each frequency contained in the modeling frequencies vector. It then uses the `abcd2s` function to convert the ABCD-parameters to S-parameters.

The `analyze` method calculates the ABCD-parameters using the physical length of the transmission line, d, and the complex propagation constant, k, using the following equations:

$\begin{array}{l}A=\frac{{e}^{kd}+{e}^{-kd}}{2}\\ B=\frac{{Z}_{0}*\left({e}^{kd}-{e}^{-kd}\right)}{2}\\ C=\frac{{e}^{kd}-{e}^{-kd}}{2*{Z}_{0}}\\ D=\frac{{e}^{kd}+{e}^{-kd}}{2}\end{array}$

Z0 is the specified characteristic impedance. k is a vector whose elements correspond to the elements of the input vector `freq`. The `analyze` method calculates k from the specified properties as k = αa + , where αa is the attenuation coefficient and β is the wave number. The attenuation coefficient αa is related to the specified loss, α, by

${\alpha }_{a}=-\mathrm{ln}\left({10}^{\alpha /20}\right)$

The wave number β is related to the specified phase velocity, Vp, by

$\beta =\frac{2\pi f}{{V}_{p}},$

where f is the frequency range specified in the `analyze` input argument `freq`. The phase velocity Vp is derived from the `rfckt.txline` object properties. It is also known as the wave propagation velocity.

• If you model the transmission line as a shunt or series stub, the `analyze` method first calculates the ABCD-parameters at the specified frequencies. It then uses the `abcd2s` function to convert the ABCD-parameters to S-parameters.

When you set the `StubMode` property to `'Shunt'`, the 2-port network consists of a stub transmission line that you can terminate with either a short circuit or an open circuit as shown in the following figure.

Zin is the input impedance of the shunt circuit. The ABCD-parameters for the shunt stub are calculated as:

$\begin{array}{c}A=1\\ B=0\\ C=1/{Z}_{in}\\ D=1\end{array}$

When you set the `StubMode` property to `'Series'`, the 2-port network consists of a series transmission line that you can terminate with either a short circuit or an open circuit as shown in the following figure.

Zin is the input impedance of the series circuit. The ABCD-parameters for the series stub are calculated as:

$\begin{array}{c}A=1\\ B={Z}_{in}\\ C=0\\ D=1\end{array}$

The `analyze` method uses the S-parameters to calculate the group delay values at the frequencies specified in the `analyze` input argument `freq`, as described in the `analyze` reference page.

## Examples

```tx1 = rfckt.txline; analyze(tx1,[1e9,2e9,3e9]); tx1.AnalyzedResult ans = Name: 'Data object' Freq: [3x1 double] S_Parameters: [2x2x3 double] GroupDelay: [3x1 double] NF: [3x1 double] OIP3: [3x1 double] Z0: 50 ZS: 50 ZL: 50 IntpType: 'Linear'```