Documentation

# detcoef

1-D detail coefficients

## Syntax

```D = detcoef(C,L,N) D = detcoef(C,L) ```

## Description

`detcoef` is a one-dimensional wavelet analysis function.

`D = detcoef(C,L,N)` extracts the detail coefficients at level `N` from the wavelet decomposition structure `[C,L]`. See `wavedec` for more information on `C` and `L`.

Level `N` must be an integer such that `1 `` N ``NMAX `where `NMAX` = `length(L)-2`.

`D = detcoef(C,L)` extracts the detail coefficients at last level `NMAX`.

If `N` is a vector of integers such that 1 ≤ `N(j)``NMAX`:

• `DCELL = detcoef(C,L,N,'cells')` returns a cell array where `DCELL{j}` contains the coefficients of detail `N(j)`.

• If `length(N) > 1`, ```DCELL = detcoef(C,L,N)``` is equivalent to `DCELL = detcoef(C,L,N,'cells')`.

• `DCELL = detcoef(C,L,'cells')` is equivalent to `DCELL = detcoef(C,L,[1:NMAX])`.

• `[D1, ... ,Dp] = detcoef(C,L,[N(1), ... ,N(p)])` extracts the details coefficients at levels `[N(1), ... ,N(p)]`.

## Examples

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This example shows how to obtain and plot the detail coefficients for an electrical current signal. This example uses zero-padding (see `dwtmode`).

Load the signal and select the first 3920 samples.

```load leleccum; s = leleccum(1:3920);```

Perform the decomposition at level 3 using db1. Extract the detail coefficients at levels 1, 2, and 3 from the decomposition structure.

```[c,l] = wavedec(s,3,'db1'); [cd1,cd2,cd3] = detcoef(c,l,[1 2 3]);```

Plot the original signal.

```plot(s) title('Original signal') ylim([0 1000])``` Plot the level 3 detail coefficients.

```plot(cd3) title('Level 3 detail coefficients (cd3)') ylim([-60 60])``` Plot the level 2 detail coefficients.

```plot (cd2) title('Level 2 detail coefficients (cd2)') ylim([-60 60])``` Plot the level 1 detail coefficients.

```plot (cd1) title('Level 1 detail coefficients (cd1)') ylim([-60 60])``` ## Extended Capabilities

### C/C++ Code GenerationGenerate C and C++ code using MATLAB® Coder™. 