Technologies of digital processing of signals and their images find more and more wide use in various areas, in particular at definition of characteristics of signals, identification of signals, for construction of multilevel systems of protection. Basic request to these are universality, speed and efficiency of performance of various procedures of processing on the basis of use of the standard inexpensive means entering into the complete set of the traditional computer technics: the personal computer, the scanner, the printer, a sound card, the modem.
The basic stage of the decision problem identification objects radio signals on parametres of radiations formed by them is connected with the complex analysis the operator of the received results of dimension of informative parametres and acceptances of the decision by it about an accessory of observable object to the set type. In existing systems this problem is solved by operator who realise monitoring of quantity indicators of characteristics of sources signals and, on a basis, identification of type of a source.
- The primary goals of information systems support identification sources of signals of radio emissions:
- Consecutive reception and the analysis characteristics source of signals.
- Accumulation informative complex estimations and characteristics of signal in DB.
- Quantitatively-time-and-frequency visualisation of informative characteristics and parametres of a signal.
- Expert visualisation identification of a source of radio emissions on the basis of visualisation of informative characteristics and parametres signal of source signal and the analysis of typical sources signal in a DB of typical sources of radio emissions.
Existing systems
Modern audio-dimension one of the most exacting operations in modern digital dimension system. For maintenance of successful audio-measurements, the software should have possibility to carry out some operations simultaneously (such as scaling of the data, a filtration, the analysis and visualisation).
There is a considerable quantity of good program digital analyzers and editors of the audiosignals intended for the visual analysis of a sound in time (oscillograms, schedules of level of capacity of a signal, etc.) and frequency (сонограммы, кепстры, etc.) areas. Among the western software products such it is necessary to note Cool Edit Pro 1.2, Dart Pro, Sound Forge, Wave Lab, Wave Studio, among domestic – SIS 5.2, «Win-Аудио», "Azure", Signal Quick Viewer 2, Signal Viewer.
In many sound editors there is a possibility to carry out the elementary processing of audiosignals in time area with a possible estimation of the received results in frequency area. However some software products, for example the special software "Azure", are capable to make difficult kinds of acoustic processing, including in frequency area, through the analysis, updating and synthesis of graphic images of a sound – under images of dynamic spectrograms. In the new version of the program "Azure" direct possibility of sample of an interesting site of the image of the dynamic spectrogram of investigated signal is realised. It is possible to put to the chosen site or own means of digital processing of images integrated into the program, or to transform it to format BMP, to use the powerful arsenal of tools given by popular graphic editors of type Adobe Photoshop. After processing of the chosen site of the image it is possible to carry out its return insert on any place on a timebase of an initial signal by the program "Azure", with the subsequent synthesis (transfer in the wave form of a sound) the modified image.
Researches
The goals of work are creation of new ways and approaches, and also working out of the corresponding software for an existing prototype of system of visualisation of real signals «Topaz», developed on cathedra PMI.
The analysis of real signals allows to draw a conclusion that the basic characteristics of frequency cuts are maximum amplitude (amplitude of peak) and the frequency corresponding to the given to amplitude (frequency of peak). On the basis of the given conclusion it is possible to assume that schedules of dependence of frequency and amplitude of peak from time are capable to present the exhaustive information on a signal.
Realisation of a mode of visualisation of schedules of frequency and amplitude of peak is perspective since it is capable to provide high degree информативности at relative simplicity of perception with the operator in comparison with already realised modes of visualisation.
According to the put task, it is necessary to visualise and process signals of the low frequencies lying in a long-wave range. Elementary example of such signal the Morse alphabet signal, which maximum frequency – 512 кGc serves radio, duration of a point and a dash (time duration of portions of signals) – 10 readout and usually are in the ratio – one to three. For signal visualisation the modelling program of such signal for system "TOPAZ" has been written (the abstract phrase of transfer is set).
Conclusions
Made analysis allows to draw a conclusion that, there are enough challenges of digital processing of sound signals and speech can be successfully solved by means of rather simple means and clear methods of digital processing of images of acoustic spectrograms.
The made numerous experiments on use of the offered approach of processing of a sound and speech through processing of their graphic images in computer systems of standard execution have shown its high potential possibilities at realisation various — even very difficult and before not realised — algorithms of processing of signals. The given approach can become base at designing of new systems of digital processing of signals.
Goal of the further researches and works is creation of new ways and approaches, and also working out of the corresponding software for visualisation of real signals and their informative characteristics, and also recognition of a signal with use of a database of signals within the limits of an existing prototype of system of visualisation of real signals «Topaz».
- Literature:
- Лукин А. Введение в цифровую обработку сигналов. - М.: Наука, 2002. - 44 с.
- Зубарев Ю.Б., Витязев В.В., Дворкович В.П. Цифровая обработка сигналов - информатика реального времени, http://www.dspa.ru/elmaterials/artic99-13.pdf
- Рябкин Ю.В. Программная система визуализации частотно-временных характеристик сигналов радиолокационных станций / Донбасс – 2020. Наука и техника – производству: Материалы 3-й научно-практической конференции. Г. Донецк, 30-31 мая 2006г. – Донецк, ДонНТУ Министерство образования и науки, 2006. - c. 13-14.
- Дворянкин С.В., Минаев В.А. Технология речевой подписи, «Открытые системы». 1997, № 5. c. 68-71.
- Основные характеристики аналогового сигнала, http://www.inforeg.org.ru/about.html
- Сазанов В. М., Парфенов Н. С. Цифровая обработка сигналов: прошлое и настоящее. Часть 1. Прошлое, http://www.computer-museum.ru/histussr/dsp.htm
- Рабинер и Голд. Теория и практика цифровой обработки сигналов, http://dsp-book.narod.ru/RG.html
- ПО «PowerGraph», http://www.powergraph.ru/soft/
- Audio Spectrum Analysis, http://www.visualizationsoftware.com/gram.html
- LabVIEW, http://ru.wikipedia.org/wiki/LabVIEW