воскресенье, 21 февраля 2010 г.

SA update to version 6.1.1.3: 24 and 32 bit

SA update to version v 6.1.1.3


We completely have changed loading of files in SA to provide support of 24 and 32 bit records. Though, in This version loading of 24 and 32 bit files is not supported yet, the loading module is optimised and prepared for solution of this task. The standard explorer is not completely correspond to necessary requirements, especially if operation with SA carries active, not incidental character.

Generall view of SA own explorer:

The standard functions are realized, the detailed description of them is not required, but nevertheless , the main possibilities are shown below.

Through PopUp menu it is possible to switch ON/switch off Hot track, to be honost it is doubtful function, mostly disturbs than helps, but in some cases it can be very useful. Also through this menu, it is possible to make at any time Update, it can be necessary, for example, if there is the selected file, and it is not visible in a mapping window by any reasons, for instance, it is placed in the end of the long list, after Update activated it will be shown.


Especially I would like to mark support of multi-channel records in this loader: maximum quantity of channels from which it is possible to select any is 16, it is not principle limitation and if there will be a necessity, the high bound can be lifted.
Fast search in a filename part works.

Some features and nuances:

In the right window the express information about file is outputed. If at construction of the list of files, the program is oriented on file's extension, then in this window the information, which is based on general analysis of contained file is outputed. That is, if wav file has txt extension at the choice of such file it will be identified as wav, and accordingly it will be also loaded as wav.

The information about standard wav files is outputed by white colour, standard for SA considered wav files with Wave Tag = 1, with digit capacity 16 bits on sample and mono. All other records demand special attention, and sometimes special approach, the information about such files is output by yellow colour, and it is the original sign to pay attention on the record, as on potentially problem and probably illiquid.

Changes of loading of files in SA are not only external, the algorithm of processing of all types of files is completely reconsidered and processed. In all previous versions there is typical enough and widespread error at standard interpretation wav as specifications, that does not give possibility to handle some quite correct wav files. In this version this error is corrected, in this connection I'd like to mark that files saved in SA version 6.1.1.3 and above, will not be correctly processed neither in SV, nor SV+, neither SA Free, nor SA Full lower versions. Once again, the problem is not in "the bad" or specially "spoilt" files, but in incorrect interpretation of the standard wav. SA saves files in strict correspondence of the specification, and these files are obliged to understand any programs, which are working with wav standard.

The next update will mention directly loading of 24 and 32 bit records, in this version the important and scale enough preparatory part, including optimisation of the code and correction of some errors in processing both wav, and mp3 standards is realised


Good Luck~

понедельник, 15 февраля 2010 г.

Scramblers: Harris AVS, Analog Voice Security

Harris AVS
Analog Voice Security

Author: SergUA6
Band Width ~2700 Hz
Low Range 300 Hz, in this example ~240-260, shift is possible
Count of Carriers 24 subchannels 112-113 Hz
Step between carriers ~112-113 Hz between centres of subchanneles
RX mode SSB

Sonograms:
pic.1 Generall view

The analogue not synchronizable scrambler, speech spectrum with band in 2700 Hz. It is broken into 24 subchannels in width approximately 112-113 Hz, these subchannels are replaced and partially inverted, time shifts are not used in this scrambler. The subchannels ocated densely without protective intervals as for example at 04XK100. Probably time shifts aren't used because of use on SW, though Codan them uses. This isn't direct inversion.

среда, 3 февраля 2010 г.

Signals. PSK: Tetra

TETRA
Professional digital trunking system, pi/4 DQPSK


Author: SergUA6
Band Width ~ 22000 Hz
Low Range ~ 2000 Hz, shift is possible, acception in SSB
Baud Rate 18000 Hz
n-Ary (PSK/MPSK) PSK-8, pi/4 DQPSK
Carrier frequency ~ 13242 Hz, shift is possible, acception in SSB
ACF ~56-57 and 14 ms
RX mode SSB

Sonograms:
pic.1 Generall view
pic.2 the signal in 4th exponantion
pic.3 the signal in 8th exponantion
Diagrams:
pic.4 manipulation speed
pic.5 Phase constellation
pic.5 ACF after PSK demodulator

TETRA - is the standard called to replace analogue systems of type PMR on VHF range. It was established approximately in 1995. From the point of view of a signal, it is easily enough recognised under the basic characteristics, such are speed of manipulation 18000 Hz and individual ACF. It is necessary to notice that, despite wide enough prevalence, there are almost no good records of this type of signals, because relvatively wideband strips IF and AF bands are required, altought we have two records with this signal, with good quality.