Broadband X-band direct frequency synthesizer and signal generation method

Abstract

The invention discloses a broadband X-band direct frequency synthesizer and a signal generation method. A crystal oscillator with high frequency accuracy and low phase noise generates a reference signal of a frequency standard generation circuit, a series of narrow dot frequencies at small frequency intervals and broad dot frequencies at large intervals are generated within a low frequency band, the narrow dot frequencies are inserted into the broad dot frequencies at the large intervals through up-conversion circuits and switching circuits to realize the function of frequency hopping at hundreds of dots, broadband signals are output through the up-conversion circuits, the switching circuits and frequency selection circuits, stray is effectively suppressed and the frequency synthesizer can realize quick frequency hopping. A designed miniature vibration isolation system can effectively reduce the influence of vibration on the phase noise. Compared with the other frequency synthesizers, the broadband X-band direct frequency synthesizer has the advantages that: an operating frequency band covers 30 percent of an X band; a stray suppression degree within a broadband range can reach more than 75dB; the phase noise is low, is -113 to -109dBc/Hz at the given frequency offset of 1KHz, and is lower than -100dBc/Hz at the given frequency offset of 1KHz; working temperature is -55 to +70 DEG C; and weight is light, and is lower than 3.7Kg.

Description

technical field [0001] The present invention relates to the fields of electronic equipment such as communication, radar, electronic countermeasures, and measuring instruments, and in particular to an X-band direct frequency synthesizer in radar equipment with wide operating frequency, low phase noise, high spurious suppression, and fast frequency hopping speed. Signal generation method. Background technique [0002] Frequency synthesizers are one of the key components of electronic equipment such as communications, radar, electronic countermeasures, and measuring instruments. Due to the continuous improvement of technical requirements for these electronic devices, a frequency synthesizer with excellent performance should have the characteristics of output frequency bandwidth, low phase noise, high spurious suppression, fast frequency hopping, and strong environmental adaptability. Direction of development. [0003] Currently, most frequency synthesizers use phase-locked sy...

AI Technical Summary

Problems solved by technology

Due to the limitations of the phase-locked loop circuit, its frequency hopping time is mostly on the order of tens of microseconds, which cannot reach the speed of 1 microsecond

If it is necessary to meet the requirements of wide-band work, the phase-locked frequency synthesizer needs a corresponding wide-band microwave voltage-controlled oscillator VCO, whose voltage control sensitivity changes greatly, and the working stability is poor when the environmental conditions change drastically.

There are also a few radar frequency synthesizers that use direct synthesis. Although their phase noise and frequency agility are also good, the working frequency band is generally only about 10%.

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