A shortwave prognosticator

Abstract

The invention relates to a short-wave pre-and-post-selector, which comprises a digital control circuit, transmitting-receiving switching circuits, band switching circuits, frequency hopping filters, a decoder, a broadband low noise amplifier and a receiving protection circuit, wherein the digital control circuit is electrically connected with an external short-wave radio station control unit through a control interface; serial codes sent by the short-wave radio station control unit are received by the digital control circuit and converted into parallel tuning codes respectively used for controlling the frequency hopping filters, the band switching circuits and the transmitting-receiving switching circuits so as to realize transmission on carrier signals different in frequency point and rapidly perform switching on carrier frequencies of useful signals; the transmitting-receiving switching circuits comprise a first transmitting-receiving switching circuit, a second transmitting-receiving switching circuit, a third transmitting-receiving switching circuit and a fourth transmitting-receiving switching circuit; the band switching circuits comprise a first band switching circuit and a second band switching circuit; the frequency hopping filters comprise a first frequency hopping filter and a second frequency hopping filter. The short-wave pre-and-post-selector disclosed by the invention has the advantages of being reasonable in structure, stable and reliable to use, strong in anti-jamming capability, low in cost, simple to control, fast in frequency hopping speed, low in power consumption, small in bottom noise and the like.

Description

technical field [0001] The invention belongs to the technical field of digital tuning and frequency hopping, and in particular relates to a short-wave preselector. Background technique [0002] With the development of frequency hopping technology, shortwave preselectors are widely used in military communication systems. It performs matching transmission for frequencies in the passband, and performs reflection attenuation for frequency mismatch in the stopband, thereby realizing signal spectrum filtering. The short-wave preselector is generally connected between the radio antenna switch and the RF amplifier, and is mainly used to improve the selectivity of the receiver. The preselector can effectively suppress out-of-band interference, improve and improve the receiver's electric field radiation sensitivity and other indicators, and ensure The receiver can work normally in complex electromagnetic environment. The short-wave post-selector is generally connected to the front en...

AI Technical Summary

Problems solved by technology

Most of the existing shortwave preselectors use single-chip microcomputer as the control circuit. The control method of singlechip is relatively complicated, and the data conversion output speed is relatively slow, which affects the frequency hopping speed of the shortwave preselector and is not conducive to the digital processing of communication equipment; in addition , since the crystal resonator is used in the single-chip microcomputer, it is easy to introduce noise in the passband of the short-wave pre-selector, which affects the communication quality

[0003] The existing short-wave pre-selector is still prone to problems: first, the amplifier on the pre-selector channel is easily damaged; second, the isolation index between the pre-selector and the post-selector cannot be improved

If the isolation between the pre-selector and the post-selector is poor, when the transmitter is working, the transmitted signal will be poured into the receiver, which will affect the receiving sensitivity and even damage the receiving channel amplifier.

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