# filtord

Filter order

## Syntax

## Description

returns the filter order for the digital filter represented as Cascaded Transfer Functions (CTF) with numerator coefficients `n`

= filtord(`B,A`

,"ctf")`B`

and denominator
coefficients `A`

.* (since R2024b)*

returns
the filter order, `n`

= filtord(`d`

)`n`

, for the digital filter, `d`

.
Use the function `designfilt`

to
generate `d`

.

returns the filter order for the filter specified by the second-order sections
matrix, `n`

= filtord(`sos`

)`sos`

. `sos`

is a
*K*-by-6 matrix. The number of sections, *K*, must
be greater than or equal to 2. Each row of `sos`

corresponds to
the coefficients of a second-order filter. The *i*th row of the
second-order section matrix corresponds to ```
[bi(1) bi(2) bi(3) ai(1) ai(2)
ai(3)]
```

.

## Examples

## Input Arguments

## Output Arguments

## More About

## Tips

## References

[1] Lyons, Richard G.
*Understanding Digital Signal Processing*. Upper Saddle River,
NJ: Prentice Hall, 2004.

## Extended Capabilities

## Version History

**Introduced in R2013a**

## See Also

`ctffilt`

| `designfilt`

| `digitalFilter`

| `isallpass`

| `isminphase`

| `ismaxphase`

| `isstable`