пятница, 17 июля 2009 г.

Updating SA to version : Now SA updates will be also described in our BLOG.

SA updating to version.

This isn't final update in series, not all things which were planned are finished yet, but there is cathegory of errors, which were removed as fast as possible. Once of such mistakes is reflected on the screenshots, which were sent by several users.

Under Windows Vista, the transgression of SA windows structure is observed at some user settings.

It makes impression of the extremely careless appearance of the program. In our opinion it is simply not acceptable for commercial products.

In version this problem is solved.

Some additions are added in the work of WaveForm module aswel.

1) The filter switch - You have just to click simply on it
The default mode is LowPassFilter, the frequency cutoff of it is manually specified from the list.

In MedianeFilter mode, the Mediane filter does work. The mediane filter has no equivalents in the analogue technique, it has special characteristics. Part of users insisted to add this Filter. The Area of Application of Mediane filter is relative enough. Generally that filter allows effectively to suppress sharp and strong impulse interferences, without distortion of fronts of the signal. In practice, on the Real signals it is necessary to estimate results

The principle of work of Mediane filter is simple enough. The signal is passed through the window, the size (2) of Which is setted by user and that size should be odd. Then the received array is sorted and as output counting the average one is taken.

Thus, if the impulse-interference has the duration, which is lesser then the window size/2, then this impulse is fully supressed.

For the absolutely qualitative work of Mediane filter it is necessary that impulses-interferences would have distance among themselves not lesser than the window size, in practice it is occuring very seldom, but nevertheless, sometimes the results of Mediane filter work are very impressing. The maximum size of the window is limited by 301 counting, further this size will be increased.

It is possible to enter any number of countings, automatically it will be added to the nearest odd number(to the bigger side) or installed at the level of 301 limit. On the big sizes of the window
speed of processing is decelerated, however it will be optimised in the near future, so this problem is not strongly serious and has the solution.

3) The oprative stepback into intial state is added. That is cancellation of all actions spent earlier with the signal. It allows quickly and effectively to pick up the necessary filter, to choose the necessary cutoff frequency and etc.

As distinct from the previous versions, the work of filters in WF module is optimised, and the resulting signal takes of precisely the same position in the displaying window as well as the initial signal.

It is nessesary to show some care In LPF mode. The frequency of a cutoff filter, as it is accepted, is setted at level -3 Db from the pass-band. For the decision of the problem of signals preservation on former positions the double-sided scheme of filtration is applied. That scheme leads to weakening on the cutoff frequency on 6 Db already. In some cases, it is not acceptable, that's why it is better to take the cutoff frequency upper and to do some passages, before recieveing the necessary result of filtration, in other it is obvious things.

Some minor problems of the whole programm are removed aswel. It is usual process thought and there is no sence to describe all the details, as it is hardly noticeably and does not have the great importance.

Good luck!