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42.8 Bogus Data Packets

Some HSP data were corrupted by bad data packets. The bad packet consists of 1930 bytes, alternating in value between 1 and 0. This replacement affected 0.0016% of the samples in a dataset, but accounted for 0.4% of the total counts, subtly affecting the statistics. The false data were injected at precisely the Nyquist frequency, helping to hide its effect in the Fourier domain. We stumbled onto this by performing statistical analysis on the raw Science Data Formatter (SDF) packets, not typically provided to users. The packets were corrupted onboard the HST, but after the data left the HSP. Several things point to this.



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