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txlineDelayLossy

Create delay lossy transmission line

    Description

    Use the txlineDelayLossy object to create a delay lossy transmission line. You can also use the txlineDelayLossy object to model a delay lossy transmission line in an RF system using the rfbudget object or the RF Budget Analyzer app.

    Creation

    Description

    dlytxline = txlineDelayLossy creates a default delay lossy transmission line object.

    example

    dlytxline = txlineDelayLossy(Name,Value) sets Properties of the delay lossy transmission line using one or more name-value arguments. For example, dlytxline = txlineDelayLossy('Z0',75) creates a delay lossy transmission line with an impedance of 75 ohms.

    Properties

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    Name of the delay lossy transmission line, specified as a string scalar or character vector.

    Example: 'Name','DLbased'

    Example: dlytxline.Name = 'DLbased'

    Characteristic impedance of the delay lossy transmission line, specified as a positive scalar in ohms.

    Example: 'Z0',75

    Example: dlytxline.Z0 = 75

    Physical length of the delay lossy transmission line, specified as a positive scalar in meters.

    Example: 'LineLength',0.0200

    Example: dlytxline.LineLength = 0.0200

    Time delay in the delay lossy transmission line, specified as a positive scalar in seconds.

    Example: 'TimeDelay',3.7e-9

    Example: dlytxline.TimeDelay = 3.7e-9

    Resistance value per unit of length of the delay lossy transmission line, specified as a positive scalar in ohm/meter.

    Example: 'Resistance',0.3400

    Example: dlytxline.Resistance = 0.3400

    This property is read-only.

    Number of input and output ports of the delay lossy transmission line, returned as positive scalar.

    This property is read-only.

    Terminals of the delay lossy transmission line, returned as a cell array.

    Object Functions

    sparametersS-parameter object
    groupdelayGroup delay of S-parameter object or RF filter object or RF Toolbox circuit object
    noisefigureCalculate noise figure of transmission lines, series RLC, and shunt RLC circuits

    Examples

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    Design a coaxial cable of 0.5 meters in length as a lossy transmission line with the characteristic impedance of 48 ohms.

    dlossy = txlineDelayLossy("Z0",48,"LineLength",500e-3);

    Calculate the noise figure at 1 GHz.

    nf = noisefigure(dlossy,1e9)
    nf = 0.0013
    

    Algorithms

    The delay lossy transmission line object calculates the S-parameters for the specified frequencies. This calculation is based on the delay line's line length, resistance, and time delay. The S-parameters are calculated using the equation given.

    S11 = 0S12 = e-pS21 = e-pS22 = 0

    Here, p = αa + (i×β). ɑa in p is the attenuation coefficient and β is the wave number.

    The attenuation coefficient, ɑa, is related to the loss, ɑ, by

    αa = (linelength × resistance)(2Z)

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

    β = 2 ×π × f × D

    where f is the frequency range specified in the S-parameters input argument.

    Introduced in R2021a