Discussion on: ''Digital Control of Interferometric Metrology Lines''

In the paper ‘Digital control of interferometric metrology lines’, the authors describe a control system to track the variations in length of a Fabry-Perot cavity by means of a frequency shifter and a piezoelectric system. The control system is applied to monitor subnanometric displacements of space telescopes, but it is interesting to note that the adopted techniques could be usefully exploited in other fields of the precision engineering.