For column vectors `x`

and `xref`

,
the mix operation is defined as `xref .* conj(x)`

.

If `x`

has multiple columns, the mix operation
applies the preceding expression to each column of `x`

independently.

The mix operation negates the Doppler shift embedded in `x`

,
because of the order of `xref`

and `x`

.

The mixing order affects the sign of the imaginary part of `y`

.
There is no consistent convention in the literature about the mixing
order. This function and the `beat2range`

function
use the same convention. If your program processes the output of `dechirp`

in
other ways, take the mixing order into account.