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Single pole multiple throw switch

  • SPnT block

RF Blockset / Circuit Envelope / Junctions


The SPnT block models a single pole multiple throw switch. This block supports both reflective and absorptive switches. You can specify two to eight output ports for the switch. The control signal is a Simulink® signal connected to the Ctl port of the block. The control signal specifies which output port transmits the input signal. When the input to the Ctl port is between one and the number of output ports, the Ctl signal value is rounded to the nearest integer. The output port that corresponds to the integer value transmits the data. If the rounded Ctl signal value does not correspond to any of the output ports, then all the output ports are turned off.



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Simulink control signal, specified as a scalar.

Data Types: double


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Insertion loss value of switch, specified as a finite scalar in decibels. Specify an insertion loss value greater than zero but less than the isolation value of the switch. For the equation, see Insertion Loss.

Isolation value of switch, specified as a scalar in decibels. Specify an isolation value greater than the insertion loss value of the switch. For the equation, see Isolation.

Switch type, specified as Absorptive or Reflective.

Number of outputs for the switch, specified as a scalar. The number of outputs must be greater than or equal to two or less than or equal to eight.

Port terminations representing matching required at all input and output ports, specified as a scalar in ohms. If you set the Load type is Absorptive, the impedance seen at all disconnected output ports is the value specified in Port terminations.

Select this parameter to internally ground and hide the reference terminals. To expose the reference terminals, clear this parameter. By exposing this terminal, you can connect it to other parts of your model.

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[1] Razavi, Behzad. RF Microelectronics. Upper Saddle River, NJ: Prentice Hall, 2011.

Version History

Introduced in R2018a

See Also

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