| 摘要 |
FIELD: radio engineering, communication.SUBSTANCE: emitted pulse consists of multiple time sections with serially varying duration; inside each time section, a quasirandom phase-modulated sequence of harmonic signal readings is generated and then converted to voltage which is passed through a low-pass filter which forms the modulation bandwidth ?F; from the output of filter, the signal is transferred to carrier frequency, power-amplified and transmitted to the antenna for radiation; reflected pulses received by the antenna are amplified, filtered at carrier frequency by a band-pass filter with transmission band ?F, time-sampled with frequency F?2?Fand level-quantised by an analogue-to-digital converter; the formed readings are transferred to zero frequency by digital quadrature heterodyning of a complex sinusoid with frequency ?F/2, and then filtered with a digital quadrature low-pass filter, readings at the output of which are formed with repetition frequency F??Fand then processed with a compression filter, the pulse characteristic of which on duration, on the phase modulation function and on the expected Doppler frequency shift is matched with the reflected pulse, wherein the delay obtained at the output of the filter of maximum signal amplitude relative the beginning of the reception cycle corresponds to distance to the detected target, and frequency of the pulse characteristic at which maximum amplitude is obtained corresponds to Doppler shift of the frequency of the target, uniquely associated with its radial velocity.EFFECT: measuring distance to targets with constant resolution in the entire range of distance and simultaneous measurement of radial velocities of targets when emitting one modulated pulse and when receiving reflected pulses, duration of which can be shorter than duration of the probing pulse.24 dwg |
