ppm: Return the ppm scale of an MRS dataset or fit result.
In neuroconductor/spant: MR Spectroscopy Analysis Tools

Return the ppm scale of an MRS dataset or fit result.

ppm(x, ft = NULL, ref = NULL, fs = NULL, N = NULL)

## S3 method for class 'mrs_data'
ppm(x, ft = NULL, ref = NULL, fs = NULL, N = NULL)

## S3 method for class 'fit_result'
ppm(x, ft = NULL, ref = NULL, fs = NULL, N = NULL)

`x`	MRS dataset of fit result.
`ft`	transmitter frequency in Hz, does not apply when the object is a fit result.
`ref`	reference value for ppm scale, does not apply when the object is a fit result.
`fs`	sampling frequency in Hz, does not apply when the object is a fit result.
`N`	number of data points in the spectral dimension, does not apply when the object is a fit result.