# Total power of PSD

Started by March 27, 2013
```Hi,

I have a Power spectral density of an EMG signal. I want to calculate total
power for different frequency ranges. (For 5-12, 15-30 and 30-60) How can I
do this using matlab?

Thank you very much for your time.
```
```Am 27.03.2013 18:32, schrieb sedab:
>
> I have a Power spectral density of an EMG signal. I want to calculate total
> power for different frequency ranges. (For 5-12, 15-30 and 30-60) How can I
> do this using matlab?

Then compute the "integral" of your PSD curve over these intervals. It
boils down to computing the average power spectral density in such an
interval and then multiplying this by the width of the interval.

average density in V^2/Hz  times  width in Hz  equals  power in  V^2.

Something like that.

```
```On Mar 28, 6:32&#4294967295;am, "sedab" <94722@dsprelated> wrote:
> Hi,
>
> I have a Power spectral density of an EMG signal. I want to calculate total
> power for different frequency ranges. (For 5-12, 15-30 and 30-60) How can I
> do this using matlab?
>
> Thank you very much for your time.

you need the area under the curve for a defined delta f
```
```On Mar 28, 6:32&#4294967295;am, "sedab" <94722@dsprelated> wrote:
> Hi,
>
> I have a Power spectral density of an EMG signal. I want to calculate total
> power for different frequency ranges. (For 5-12, 15-30 and 30-60) How can I
> do this using matlab?
>
> Thank you very much for your time.

a far easier way is to bandpass filter the signal and compute the
variance (assuming no dc). This is the same as the average power.
```