## 3.20 `T`: Transmission Line

### 3.20.1 Syntax

`T`*xxxxxxx n1+ n1– n2+ n2–* {*args*}

`.tline` *xxxxxxx n1+ n1– n2+ n2–* {*args*}
### 3.20.2 Purpose

Lossless transmission line.
### 3.20.3 Comments

*N1+* and *n1–* are the nodes at one end. *N2+* and *n2–* are the nodes at the other end.

The parameters `TD`, `Freq`, and `NL` determine the length
of the line. Either `TD` or `Freq` and `NL` must be
specified. If only `Freq` is specified, `NL` is assumed to be
.25. The other will be calculated based on the one you specify. If
you specify too many parameters, `Freq` and `NL` dominate, and
a warning is issued.
### 3.20.4 Element Parameters

Many parameters are offered. You should not specify them all.

#### Parameters that always work.

`LEN` = *x*-
Length multiplier. (Default = 1) The effective length, regardless of
its method of calculation is multiplied by this number.

#### Direct specification of electrical characteristics.

`Z0` = *x*-
Characteristic impedance. If not specified, it is calculated by
√(
*L*/*C*). If neither `Z0` nor `L` and `C` are
specified, the default value is 50 Ohms.

`TD` = *x*- Time delay. If not specified, it will be calculated, either by
*NL*/*FREQ* or by √(*L* *C*).

`FREQ` = *x*- Frequency for NL.

`NL` = *x*- Number of wavelengths at
*Freq*.

#### Physical parameters

`L` = *x*-
Inductance per unit length. This value is used only if
`Z0` and
`TD` are not specified.

`C` = *x*-
Capacitance per unit length. This value is used only if
`Z0` and
`TD` are not specified.

### 3.20.5 Probes

The standard probes for all basic elements are all available. See the
`print` command for documentation.