# smm2s

Convert mixed-mode 2N-port S-parameters to single-ended 4N-port S-parameters

## Syntax

``s_params = smm2s(s_dd,s_dc,s_cd,s_cc)``
``s_params = smm2s(s_dd,s_dc,s_cd,s_cc,option)``

## Description

example

````s_params = smm2s(s_dd,s_dc,s_cd,s_cc)` converts mixed-mode, N-port S-parameters into single-ended, 2N-port S-parameters, `s_params`. `smm2s` maps the first half of the mixed-mode ports to the odd-numbered pairs of single-ended ports and maps the second half to the even-numbered pairs.```
````s_params = smm2s(s_dd,s_dc,s_cd,s_cc,option)` converts the S-parameter data using the optional argument `option`. You can also reorder the ports in `s_params` using the `snp2smp` function.```

## Examples

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Convert between mixed-mode and single-ended S-Parameters.

Create mixed-mode S-Parameters:

```S = sparameters('default.s4p'); s4p = S.Parameters; [sdd,scd,sdc,scc] = s2smm(s4p);```

Convert them back to 4-port, single-ended S-Parameters.

`s4p_converted_back = smm2s(sdd,scd,sdc,scc);`

Display the single-ended S-Parameters at the first frequency.

`s4p_converted_back_new = s4p_converted_back(:,:,1)`
```s4p_converted_back_new = 4×4 complex 0.0857 - 0.1168i -0.5372 - 0.6804i 0.0966 - 0.0706i 0.0067 + 0.0053i -0.5366 - 0.6860i 0.0803 - 0.1234i 0.0059 + 0.0048i 0.0977 - 0.0703i 0.0957 - 0.0700i 0.0067 + 0.0048i 0.0818 - 0.1104i -0.5362 - 0.6838i 0.0055 + 0.0051i 0.0972 - 0.0703i -0.5376 - 0.6840i 0.0761 - 0.1180i ```

## Input Arguments

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S-parameters, specified as a complex N-by-N-by-K array containing K matrices of common-mode, N-port S-parameters (Scc).

S-parameters, specified as a complex N-by-N-by-K array containing K matrices of cross-mode, N-port S-parameters (Scd).

S-parameters, specified as a complex N-by-N-by-K array containing K matrices of cross-mode, N-port S-parameters (Sdc).

S-parameters, specified as a complex N-by-N-by-K array containing K matrices of differential-mode, N-port S-parameters (Sdd).

Port order, a scalar, specified as `1`, `2`,or `3`. Port order determines how the function orders the ports:

• `1``smm2s` maps the first half of the mixed-mode pairs to odd-numbered pairs of single-ended ports and maps the second half to even-numbered pairs. For example, in a mixed-mode, 4-port network:

• Port 1 becomes single-ended ports 1 and 3.

• Port 2 becomes single-ended ports 5 and 7.

• Port 3 becomes single-ended ports 2 and 4.

• Port 4 becomes single-ended ports 6 and 8.

• `2``smm2s` maps the first half of the mixed-mode pairs to single-ended ports in ascending numerical order, followed by the second half, also in ascending order. For example, in a mixed-mode, 4-port network:

• Port 1 becomes single-ended ports 1 and 2.

• Port 2 becomes single-ended ports 3 and 4.

• Port 3 becomes single-ended ports 5 and 6.

• Port 4 becomes single-ended ports 7 and 8.

• `3``smm2s` maps the first half of the mixed-mode pairs to single-ended ports in ascending numerical order. The function maps the second half to pairs of ports in descending order. For example, in a mixed-mode, 4-port network:

• Port 1 becomes single-ended ports 1 and 2.

• Port 2 becomes single-ended ports 3 and 4.

• Port 3 becomes single-ended ports 8 and 7.

• Port 4 becomes single-ended ports 6 and 5.

## Output Arguments

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S-parameters, returned as a 2N-by-2N-by-K array of complex numbers representing K single-ended, 2N-port S-parameters.

## References

[1] Granberg, T.,.Handbook of Digital Techniques for High-Speed Design.Upper Saddle River, NJ: Prentice Hall, 2004.

## Version History

Introduced in R2009a