Broadband low-phase-noise step frequency synthesizer and frequency synthesizing method

Abstract

The invention discloses a broadband low-phase-noise step frequency synthesizer and a frequency synthesizing method. The synthesizer comprises a controller, an analog-to-digital converter, an integrated phase discriminator, an analog switch, a broadband VCO, a coupler, a broadband amplifier, a mixer, a first low-pass filter, a second low-pass filter, a radiofrequency amplifier, a comb spectrum generator and a crystal oscillator. The broadband low-phase-noise step frequency synthesizer and the frequency synthesizing method combine the comb spectrum generator and a PLL, achieves not only a broadband but also ultralow phase noise by using the frequency selection function and the frequency division function of the PLL, realize a fine stepping capability without using DDS, and can simultaneously achieve broadband low-phase-noise fine stepping and a small size and low power consumption.

Description

technical field [0001] The invention relates to the technical field of radio frequency microwave frequency sources, in particular to a broadband low phase noise fine step frequency synthesizer and a frequency synthesis method. Background technique [0002] Frequency synthesizer is one of the key components of microwave radio frequency conversion components, widely used in radar, reconnaissance, wireless monitoring and communication systems. In recent years, with the deterioration of the electromagnetic environment, the requirements for receiver sensitivity and resolution have become higher and higher, and the frequency synthesizer has a direct impact on this index. Therefore, modern communication has a direct impact on the performance of the frequency synthesizer, such as phase noise, frequency step, etc. , also put forward higher requirements. At present, broadband frequency synthesizers mainly rely on frequency mixing or frequency multiplication to expand bandwidth. This ...

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Problems solved by technology

At present, broadband frequency synthesizers mainly rely on frequency mixing or frequency multiplication to expand bandwidth. This method usually requires a large number of filters, resulting in large volume and high power consumption; the realization of conventional fine stepping mainly relies on DDS, and DDS is usually limited by the device. Output frequency The frequency source is not high, the bandwidth is not wide, and the frequency source with low phase noise usually adopts analog direct synthesis method, such as comb spectrum generator, PDRO, etc. Usually, fine stepping is not possible, but fine stepping needs to be combined with DDS, and the broadband fine stepping frequency is conventionally realized Synthesizers are bulky and power-hungry

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