Model fitting by least squares |

Multiplication in the Fourier domain is **convolution** in the time domain.
Fourier-domain division is time-domain **deconvolution**.
This division is challenging when has observational error.
Failure erupts if zero division occurs.
More insidious are the poor results we obtain
when zero division is avoided by a near miss.

- Dividing by zero smoothly
- Damped solution
- Smoothing the denominator spectrum
- Imaging
- Formal path to the low-cut filter
- The plane-wave destructor

2014-12-01