rfckt.delay

Delay line

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

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

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

rfdata.data object

This property is read-only.

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

'Loss' — Line loss value

positive scalar in dB

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

Name — Object name

1-by-N character array

This property is read-only.

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

Data Types: char

nport — Number of ports

positive integer

This property is read-only.

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

Data Types: double

'TimeDelay' — Amount of time delay

scalar in seconds

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

Data Types: double

'Z0' — Characteristic impedance

scalar in ohms

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

Data Types: double

Object Functions

analyze	Analyze circuit object in frequency domain
calculate	Calculate specified parameters for circuit object
circle	Draw circles on Smith Chart
listformat	List valid formats for specified circuit object parameter
getz0	Characteristic impedance of transmission line object
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 object parameters with y-axes on both left and right sides
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

Examples

Represent Delay Lines

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.

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

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

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

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.