# rfckt.delay

## Description

Use the `delay` class to represent delay lines that are characterized by line loss and time delay.

## Creation

### Syntax

``h = rfckt.delay``
``h = rfckt.delay('Property1',value1,'Property2',value2,...)``

### Description

example

````h = rfckt.delay` returns a delay line object whose properties are set to their default values.```
````h = rfckt.delay('Property1',value1,'Property2',value2,...)` sets properties using one or more name-value pairs. For example, `rfckt.delay ('Loss',2)`creates an RF delay line with a line loss of 2 dB. You can specify multiple name-value pairs. Enclose each property name in a quote```

## Properties

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Computed S-parameters, noise figure, OIP3, and group delay values, specified as a rfdata.data object. For more information refer, Algorithms.

Data Types: `function_handle`

Line loss value, specified as a positive scalar in dB. Line loss is the reduction in strength of the signal as it travels over the delay line . The default value is `0`.

Data Types: `double`

Object name, specified as a `1-by-N` character array.

Data Types: `char`

Number of ports, specified as a positive integer. The default value is 2.

Data Types: `double`

Amount of time delay introduced in the line, specified as a scalar in seconds. The default value is `1.0000e-012`.

Data Types: `double`

Characteristic impedance of the delay line, specified as a scalar in ohms. The default value is `50`.

Data Types: `double`

## Object Functions

 `analyze` Analyze RFCKT object in frequency domain `calculate` Calculate specified parameters for rfckt objects or rfdata objects `circle` Draw circles on Smith Chart `extract` Extract specified network parameters from rfckt object or data object `listformat` List valid formats for specified circuit object parameter `listparam` List valid parameters for specified circuit object `loglog` Plot specified circuit object parameters using log-log scale `plot` Plot specified circuit object parameters on X-Y plane `plotyy` Plot specified parameters on X-Y plane with Y-axes on both left and right sides `getop` Display operating conditions `polar` Plot specified object parameters on polar coordinates `semilogx` Plot specified circuit object parameters using log scale for x-axis `semilogy` Plot specified circuit object parameters using log scale for y-axis `smith` Plot specified circuit object parameters on Smith chart `write` Write RF data from circuit or data object to file `getz0` Get characteristic impedance of transmission line object `read` Read RF data from file to new or existing circuit or data object `restore` Restore data to original frequencies `getop` Display operating conditions `groupdelay` Group delay of S-parameter object or RF filter object or RF Toolbox circuit object

## Examples

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Represent delay lines that are characterized by line loss and time delay using rfckt.delay.

`del=rfckt.delay('TimeDelay',1e-11)`
```del = rfckt.delay with properties: Z0: 50.0000 + 0.0000i Loss: 0 TimeDelay: 1.0000e-11 nPort: 2 AnalyzedResult: [] Name: 'Delay Line' ```

## Algorithms

The `analyze` method treats the delay line, which can be lossy or lossless, as a 2-port linear network. It computes the `AnalyzedResult` property of the delay line using the data stored in the `rfckt.delay` object properties by calculating the S-parameters for the specified frequencies. This calculation is based on the values of the delay line's `loss`, α, and time delay, D.

`$\left\{\begin{array}{c}{S}_{11}=0\\ {S}_{12}={e}^{-p}\\ {S}_{21}={e}^{-p}\\ {S}_{22}=0\end{array}$`

Above, p = αa + , where αa is the attenuation coefficient and β is the wave number. The attenuation coefficient αa is related to the loss, α, by

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

and the wave number β is related to the time delay, D, by

`$\beta =2\pi fD$`

where f is the frequency range specified in the `analyze` input argument `freq`.

## References

[1] Ludwig, R. and P. Bretchko, RF Circuit Design: Theory and Applications, Prentice-Hall, 2000.

Introduced before R2006a