M.S. Baranova – JSC «MSDB «Almaz-Antey» named after A. A. Raspletin», Moscow. E-mail: firstname.lastname@example.org
S.N. Filin – JSC «MSDB «Almaz-Antey» named after A. A. Raspletin», Moscow
The general tendency of development modern radar station (RS) is wide use of various kinds of complex signals. Signals concern complex signals with the big base, at which product of width of a spectrum on duration of a signal of essentially more unit. Thus requirements to accuracy and stability of parametres of formed signals constantly increase. Traditional analogue methods of formation of complex signals in some cases do not meet the increased requirements, as has predetermined interest to digital shapers of signals. Digital methods of formation provide high long-term stability and repeatability of parametres of signals.
The developed digital shaper of radar-tracking signals (DSRTS) is intended for generation on intermediate frequency of probing radio-frequency signals. He allows to form principal views of the signals applied in modern RS, such as pulse signals with linear frequency modulation (LFM) and phase-code modulation (PCM), and also supposes possibility of formation of signals with frequency-code manipulation (FCM), nonlinear frequency modulation (NFM), quasi-continuous signals - not modulated (NM) and with linear frequency modulation on a pack of impulses (LFM on a pack).
DSRTS it is realised on the basis of a microcircuit of direct digital synthesis (DDS). The algorithm and the software allowing in real time to change parametres and an operating mode of the device according to received from central computer complex by the information have been developed for control DSRTS. Adjustment DSRTS for a certain operating mode is made by the signal processor before the beginning of a corresponding cycle of work by means of programming of microcircuit DDS through SPI the interface. All parts of the shaper also work under control of the processor providing reception and transfer of commands of control, loading of data in registers EPLD during the corresponding moments of time and the control of a condition of separate knots of the shaper.
The instructions on formation of concrete type of a signal arrive in the form of an operating package on the processor from central computer complex before the beginning of a new cycle of work RS. Work realisation in real time needed working out of the scheme of synchronisation and formation of operating impulses on a crystal EPLD.
DSRTS on the basis of microcircuit DDS possesses useful possibility on formation LFM-signals in a wide range of reorganisation of frequency and duration.
Generalising results of test tests DSRTS it is possible to note the following:
spectrum forms of the signals correspond to the theory and results of modelling;
out of a working band of frequencies of the shaper level of parasitic spectral components does not exceed -50 …-60 dB concerning a maximum of a spectrum of a signal;
control possibility in real time is realised;
wide-band reorganisation of a band of a formed signal with high speed and the high permission on frequency and a phase is provided.
DSRTS it is developed on the basis of programmed microcircuits that provides possibility of formation of various kinds of probing signals by updating of the software and a file of burning EPLD without design debugging of the device.