Used to upsample a Wave object. The upsampled sample rate must be an natural multiple of the current sample rate.

## Arguments

- wave
Wave object to upsample.

- upsample.rate
The sample rate to upsample to.

- method
"basic" for linear, or a function to interpolate NAs in a vector

## Examples

```
wave <- tuneR::sine(4000, samp.rate=44100)
wave2 <- upsample(wave, 88200)
```