[daip] Reference spectral pixel in AVSPC

[Eric Greisen]

Richard Rand wrote:
> Hi Eric,
> 
> Thanks for the reply.  Can you then tell me if there is a way to 
> regrid/interpolate/frequency-shift uv data so that I can move the 
> reference frequency back to an integer pixel (center of a pixel)?  I am 
> trying to grid one uv data set onto the grid of another which has twice 
> the channel width, but both data sets have the same reference velocity 
> at an integer pixel.  Hope that makes sense!

If I understand, you need to interpolate a data set onto a new grid of 
channels.  (The freq axis is linear and you can just adjust the ref 
frequency and ref pixel accordingly.  But that will change the ref 
velocity also.)  It is possible that SPECR will do what you need.  It 
does things by FFT so you might wish to work with the finer resolution 
data to start.  FFT of an undersampled line does bad things!

Eric Greisen