High/intermediate-frequency front-end circuit of digital short-wave receiver

Abstract

The invention relates to a high / intermediate-frequency front-end circuit of a digital short-wave receiver, which mainly comprises a PIN diode electric control attenuator, digital control electric tuning preselected tracking filter groups, a gain control low-noise amplifier, a direct digital frequency synthesizer, a plurality of frequency mixers, an intermediate-frequency amplifier, an amplitude detection and grain control circuit and a preselected controller, wherein a weak signal sensed by an antenna is subjected to tracking frequency selection by the first digital control electric tuning preselected tracking filter group after passing through the PIN diode electric control attenuator and then is subjected to frequency selection by the second digital control electric tuning preselected tracking filter group after being amplified by the gain control low-noise amplifier, the signal after being subjected to frequency selection is subjected to frequency mixing three times with the plurality of frequency mixers by three local oscillators formed by the frequency synthesizer and is transmitted to a demodulator for demodulation after being subjected to multistep intermediate-frequency amplification and gain control processing. The high / intermediate-frequency front-end circuit of the digital short-wave receiver can meet the requirement of high sensitivity, strong anti-interference performance and wide dynamic range for the short-wave receiver, is suitable for a frequency-hopping receiving machine with rapid frequency change and has the effects of low insertion loss, low in-band ripple and high selectivity.

Description

technical field [0001] The invention belongs to the technical field of short-wave radio communication, and in particular relates to a high-frequency front-end circuit of a numerically controlled short-wave receiver. Background technique [0002] The electromagnetic environment of modern radio communication is becoming more and more complex, the short-wave radio communication equipment has increased a lot, and the signal has become more and more crowded. For example, when multiple radio stations are working at the same time, due to the short distance, they will interfere with each other, and in severe cases, the shortwave receiver will be blocked and cannot be used. In addition, with the advancement of modern communication technology and the current developments such as electronic countermeasures, electronic reconnaissance and anti-reconnaissance, new technical requirements are put forward for the high-frequency front-end circuit of the radio receiver, so the design has anti-...

AI Technical Summary

Problems solved by technology

[0003] In the design of short-wave radio communication equipment, designers often focus on digital intelligent functions, and often ignore the high-index circuit design of analog high-frequency front-end circuits. For example, some designs use short-wave radio signals received by antennas through the passband frequency. After the wideband bandpass filter, the down-mixing process is performed. Obviously, this will lead to a serious decline in some performance indicators of the high-frequency front-end circuit, such as intermediate frequency anti-distance ratio, image anti-distance ratio, and anti-blocking.

According to the problem of poor anti-blocking interference performance of some short-wave radio communication equipment, some methods such as the phase cancellation method have also been proposed and used, but it cannot adapt to the rapid changes in parameters during the use of short-wave communication receivers in motion.

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