вторник, 5 октября 2010 г.

SA Update to version v

SA Update to version v

In this version speed of calculations, at search of a correlative triangle in OFDM module, is increased non less then 30%.

The algorithm of resampling of records is completely reconsidered.

Earlier we marked, that resampling algorithm in SA though provides precision accuracy on sampling rate, nevertheless distorts Amplitude frequency characteristic/Phase frequency characteristic (AFC/PFC) of signals. Though, it does not have the great importance in overwhelming majority of cases, as distortions affect the upper part of a spectrum. But the problem exists, we knew about it, and we promised whenever possible to solve it.

The problem is most brightly shown at resampling of OFDM signals, as OFDM signals are very sensitive to this sort of distortions.

In current version, resampling function works practically with absolute accuracy, in reasonable limits of course.

It is most easier to show the difference on the sonograms.


An old algorithm: there are distortions AFC/PFC on the upper channels of OFDM signal, which are visible even on sonogram.

New algorithm: there are no distortions.


An old algorithm: resampling of the record with sampling rate 68 mHz, on 60 mHz. As anti-alias filters aren't used, manual pre-processing is demanded, for removal of unnecessary components of the spectrum.

New algorithm: an excellent quality. Anti-alias filters are used by default. Although it isn't the main criteria of qualitative resampling, nevertheless it strongly simplifies operation with resampling function , excepting manual pre-processing.

Also the minor bug, which were found out by our users are solved.
Good luck!