B.G. Karas − Leading Engineer,
JSC SPE «PROTEK» (Voronezh, Russia)
E-mail: twx@mail.ru
V.A. Shuvaev – Ph.D. (Eng.), Associate Professor, General Director,
JSC SPE «PROTEK» (Voronezh, Russia)
Е-mail: protek@protek-vrn.ru
Target statement.The major features of any radiocommunication system is energy and spectral efficiency, specifically its power consumption and the frequency interval it occupies, which is essential for message transmission. Most advanced high-frequency and microwave transmitters use angular modulation which generally has an infinite spectrum. In real transmitters, frequency interval is limited in order to maintain electromagnetic compatibility up to the width defined by Nyquist criterion. As a result of filtration, transmitted signal gains parasitic amplitude modulation, whose ratio tends towards infinity. In practice, this means that the signal’s maximal level significantly exceeds the average one (peak factor’s large values). This leads to high signal distortions and spectral effectivity reduction due to unwanted spectrum expansion.
Objective. To develop a method to reduce the value of PSK-signal’s peak factor using Hilbert’s transform.
Results. The developed method is based on Hilbert’s transform and allows to use the same element base (in other words, using amplifiers with the same output capacity) in order to receive signal with greater total capacity at less distortion. As Hilbert’s transform is biunique, each component of the resulting signal bears all the information contained in the original signal. Thisenhancesthesystem’sinterferenceresistanceasitcanreceivealltheundistorted information in orthogonal interference of polarization being exposed to interference of any fixed polarization.
Practical implementation. The developed method can be effectively used to reduce the peak factor values of PSK-signal formed by interference transmitters targeted at the global navigation system.
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