Engee documentation

groupdelay

Calculation of the group delay of S-parameters, RF filter, or circuit object.

Library

EngeeRF

Syntax

Function call

  • gd = groupdelay(sparamobj) — calculates the group delay of the S-parameter object at the frequencies specified in the S-parameter object file. Argument sparamobj it can be an S-parameter object or an object nport.

  • gd = groupdelay(sparamobj,i,j) — calculates the group delay for a specific . If i and j not specified, the group delay is calculated by for two-port facilities and for non-two-port facilities.

  • gd = groupdelay(rfobj,freq) — calculates the RF group delay of an object rfobj at the specified frequencies freq.

  • gd = groupdelay(rfobj,freq,Name=Value) — calculates the group delay using additional parameters specified by one or more arguments of the type «name-value».

Arguments

Input arguments

# sparamobj is an object of S-parameters

+ object

Details

An object of S-parameters. The function uses the object’s data to calculate the group delay.

# rfobj — RF object

+ chain object | the rffilter object | transmission line object | the seriesRLC object | shuntRLC object | RF network object

Details

An RF object defined as one of the following objects:

Chain Object

circuit

RF Filter Object

rffilter and lcladder

Transmission Line Objects

Serial and parallel RLC objects

seriesRLC and shuntRLC

RF network objects

# freq — frequencies at which the group delay is calculated

+ vector

Details

The frequencies at which the group delay is calculated, given as a vector of positive real numbers.

# i,j — port numbers of the S-parameter object or RF object

+ scalars

Details

Port numbers of the S-parameter object or RF object, specified as scalar integers.

Input arguments «name-value»

Specify optional argument pairs as Name=Value, where Name — the name of the argument, and Value — the appropriate value.

Example: gd = groupdelay(filter, frequency, Aperture = 50). You can specify multiple pairs «name-value».

# Aperture — width of two frequency points

+ freq*sqrt(eps) (by default) | scalar | vector

Details

The width of two frequency points, specified as a real positive scalar or vector.

Типы данных

Float64

# Impedance — the impedance of the S-parameters

+ scalar

Details

The impedance of the S-parameters, set as a real positive scalar. Default impedance values for various objects:

  • 50 — LC objects-ladders and chains;

  • obj.impedance — S-parameter objects;

  • obj.networkdata.impedance — N-port objects.

Типы данных

Float64

Output arguments

# gd — group delay

+ scalar

Details

The group delay returned as a scalar in seconds.

Examples

Group delay of the RF filter object

Details

Let’s calculate and plot the group delay of the RF filter object in the frequency range 0.5–3.5 GHz.

using EngeeRF

r = rffilter(FilterType = "Butterworth", ResponseType = "Bandpass")
freq = range(0.5e9, 3.5e9, length=1001)
gd  = groupdelay(r, freq)
plot(freq/1e9, gd, xlabel = "Frequency (GHz)", ylabel = "Group delay (seconds)")

groupdelay

Group delay of a two-wire transmission line

Details

Let’s create a two-wire transmission line with the following properties:

  • Radius — 0.5 mm;

  • Dielectric thickness — 1.088 mm;

  • Dielectric constant — 1.0054.

using EngeeRF

twowiretxline = txlineTwoWire(Radius = 0.5e-3, EpsilonR = 1.0054, Separation = 1.088e-3)

Calculate the group delay of the transmission line at the frequency 2.5 GHz.

freqs = [2.5e9, 2.5e9 + 1e3]
gd = groupdelay(twowiretxline, freqs)
2-element Vector{Float64}:
 3.3446468622312824e-11
 3.3446468622312824e-11