3.20  T: Transmission Line

3.20.1  Syntax

Txxxxxxx n1+ n1– n2+ n2– {args}
.tline xxxxxxx n1+ n1– n2+ n2– {args}

3.20.2  Purpose

Lossless transmission line.


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.