Continuous Phase Measurement in the W7-X Infrared Interferometer by Means of a FPGA and High-Speed ADCs

Development of Efficient FPGA-Based Multi-Channel Phase Meters for IR-Interferometers

“…The performance of the phase measuring algorithm depends on the number of samples per period of the signáis [6]- [8]. Considering directly the signáis at the output of the ADCs, the valué of this parameter is 105/40 = 2.625 Samples/period, which is below the minimum number required, (>4) for the interpolation algorithm to work correctly [6].…”

“…For several experimental campaigns an off-line phase measuring system has been used [6] and recently an FPGA-based online processing system has been tested and installed for the one-channel arrangement [7]. In addition, several tests have also been successfully carried out on the IR interferometer test-bench at IPP-Greifswald [8]. Fig.…”

“…As aforementioned, Afa and A(f> 2 are the phase differences between the output interference signáis of each interferometer and their correspondent references. The calculation of these phase differences should be performed by a proper phase measuring algorithm, in this case by an interpolation algorithm [6]- [8]. However before carrying out this process the signáis must be digitized and pre-conditioned.…”

Interferometry for Fusion Devices

“…The line-electron density measurement at W7-X will require a precision of 10 18 m −2 , as it is described in Esteban, Sánchez, Sánchez, Kornejew, Hirsch, López, Fernández & Nieto-Taladriz (2010) the electronic filters needed to split both frequency components (CO 2 and CO interference signals), must have an attenuation in the rejection band of 43 dB. This task has been solved using digital filters Esteban, Sánchez, Sánchez, Kornejew, Hirsch, López, Fernández & Nieto-Taladriz (2010) …”

“…This task has been solved using digital filters Esteban, Sánchez, Sánchez, Kornejew, Hirsch, López, Fernández & Nieto-Taladriz (2010) …”