SA update to version 6.2.2.5

SA update to version 6.2.2.5

Automatic synchronization of phase added in FSK-2 dem module.

The presence of two degrees of adjustment (in phase and frequency) for setting/selecting accurate clock for many presents certain difficulties. As miminum the phase synchronization can be achieved fairly quickly and qualitatively, in automatic mode.

This is implemented in the current update.


If the automatic phase is ON(enabled by default) setting the exact value of the clock frequency is greatly simplified. In addition, in most cases, automation will work better and error free.

Nevertheless, the possibility of a transition to a fully manual mode is preserved, sometimes it's necessary.

Automation mode helps to significantly over short and very short signal/fragments.

Algorithm for automatic phasing is not sensitive to the long series of zeros or ones at the beginning of the fragment, it usually is the problem seriously. This situation handled correctly, however, should not take very long series. Also not recommended to take when copying or selection, start part of signal with noise, this can completely disrupt the work of the algorithm.

Although algorithm was developed an for signals FSK-2, he copes with C4FM, which greatly facilitates the identification of this regime and etc.

In general, the automatic phase synchronization, when set properly of clock frequency. Guarantees a correct bitstream and greatly simplifies the module FSK-2 demodulator in SA.

Generally, issues guarantees the correctness of the bitstream is a separate issue, which many prefer to sidestep/not see. :-)

Good Luck!

SA update to version 6.2.2.4

SA update to version 6.2.2.4

Under a 64-bit OS (Vista, W7) are errors in the previous version.

The current version of SA 6.2.2.4 passed rigorous testing, all identified problems are eliminated. This version very stable and sustainable for both 32-bit OS, and 64-bit.

Good Luck.

Update SA to version 6.2.2.0/1

Update SA to version 6.2.2.0/1

In this version added the ability to copy the various fragments of the signal from WF module.

Copy fragments signal from the sonograms, can not operate sufficiently exactly. This is not a problems of SA, it is a fundamental limitation FFT.

The fact that the FFT, in general case , makes a transition from time domain into the frequency domain, and such a thing as time loses its meaning. Within the FFT block does not have time, and to say exactly where in that block is one or another component of the spectrum is impossible. This leads to the fact that selecting/separating out a segment of the signal at the sonograms, there is always uncertainty within the block FFT. Sometimes this quantity is large enough. Hundreds of milliseconds or few seconds and more, depending on size of block FFT.

Copying a fragments of the signals as waveform is much more accurate, but has own problems. Impossible to say exactly, from the image of waveform, exist/included a some frequency components in the selected segment or no.

Although the selection of segments from by waveform and is much more accurate, nevertheless, also not an accurate method. Accuracy is limited to one or two samples. In general, the problem is really accurate measurements and actions, is surprisingly/unexpectedly deep and multifaceted task.

Also introduce the possibility of transferring a fragment of the signal directly in the FSK-2 dem, and solves the problem of obtaining "clean" bit stream, in many difficult cases.

A small example of obtaining a "pure" bit stream from the rather complicated to demodulate the signal.






As usual, apart from updates, fixed bugs found by users. And including minor corrections to improve the work of the various modules and the whole program.


Good Luck!

Update SA to version 6.2.1.8

Update SA to version 6.2.1.8

In this version, we fixed an error in the function of BRC (Baud Rate Correction) discovered by users, and introduce/added a two modifications.

The first.


Sometimes, it is easier to work with a relative or even abstract concepts, because no matter the specific values, but important that they fit into a certain framework. This applies to the oversampling and shifting of signal by frequency.

Usually, it is required that a signal was in the middle of the spectrum, and the sampling frequency was not much excess.

In this version You can select the frequency shift or frequency oversampling, just selecting the desired point from the list. In some cases, it greatly reduces the time and effort. Possibility of manual input for precise actions, of course, also saved.

The second

VMW module can potentially provide extremely high accuracy, at the request of Spanish colleagues, we insert in the current update stroboscopic method of measurements.

The idea is that, if the data in the record is sufficient, You can get very precise parameters of the signals.

However, there are problems, large amounts of data require very large computing and time.

Given the characteristics of the module VMW, we just calculate and to display every 1 st, 2 nd, 4 th etc lines/rows in the visualization VMW. For all the simplicity and elegance of this method, it provides exellent/perfectly accuracy of measurement.

This is one of the realizations of the stroboscopic measurement method. And like all such methods, it provides increased accuracy with increasing period gating, in this case by rows.

In the screenshot above, perfectly clear that the old method to accurately measure the period of the sine (exactly 1000 Hz) is extremely difficult, error of 20 nanoseconds is not noticeable. In really, an error and in 100 nanoseconds is very difficult to visually detect the slope of the lines is enough small.

A new method for gating each 1024 lines, clearly and accurately detect the difference in a nanosecond! Actually the accuracy is increased compared with the first/old method in 1024 times.

Need to be cautious, as stroboscopic methods for periodic signals may give a false and sometimes very misleading results, due to skip of parts of signal. To prevent this, you should always start measuring without gating. And gradually increasing the accuracy to measurement via of gating.

Good Luck!

SA Update to version v 6.2.1.6

SA Update to version v 6.2.1.6

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 6.2.1.6, resampling function works practically with absolute accuracy, in reasonable limits of course.

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

1

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.

2

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!