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CN-122001368-A - Low phase noise signal generating device

CN122001368ACN 122001368 ACN122001368 ACN 122001368ACN-122001368-A

Abstract

The invention discloses a low-phase noise signal generating device, which belongs to the technical field of low-phase noise signal generation and comprises a power supply module, a VPX main control board, a baseband unit, a reference unit, a local oscillator and clock unit, a frequency reference unit and an output unit, wherein the reference unit is used for generating a low-phase noise reference signal, the local oscillator and clock unit is used for generating a clock signal and a local oscillator signal with low phase noise, and the baseband unit is used for generating a baseband signal with low phase noise. The frequency reference unit obtains a wideband fine stepping frequency reference signal, and the output unit finally generates an output signal of 10MHz to 40 GHz. The low-phase noise signal generating device perfectly combines the fine frequency resolution advantage of the DDS technology with the broadband and low-phase noise advantage of the analog direct frequency synthesis technology through the original three-stage architecture of 'baseband DDS fine stepping generation + local oscillator PLL large stepping phase locking + direct frequency synthesis filling'. Finally, the ultra-wide range of the output signal frequency coverage of 10MHz to 40GHz is realized, while extremely fine frequency stepping is maintained.

Inventors

  • HE WEI
  • WANG XINYANG
  • JIA ZHIGUO
  • TIAN YUNFENG
  • LI DONGLIANG

Assignees

  • 北京无线电计量测试研究所

Dates

Publication Date
20260508
Application Date
20251226

Claims (7)

  1. 1. The low-phase noise signal generating device is characterized by comprising a power supply module, a VPX main control board, a baseband unit, a reference unit, a local oscillator and clock unit, a frequency reference unit and an output unit; The VPX main control board mainly completes the internal control and external data communication functions of the low-phase noise signal generating device; The reference unit adopts a phase-locked frequency synthesis mode to realize the generation of a low-phase noise reference signal; The local oscillator and clock unit generates a clock signal and a local oscillator signal with low phase noise based on the low phase noise reference signal; the baseband unit generates a low-phase noise baseband signal based on the low-phase noise clock signal; The frequency reference unit expands the baseband signal with low phase noise to the frequency of 6-12 GHz by utilizing a frequency mixing technology to obtain a broadband fine stepping frequency reference signal; The output unit is based on the broadband fine stepping frequency reference signal, and realizes the frequency expansion of low phase noise through frequency multiplication, frequency division and filtering treatment, and finally generates an output signal of 10MHz to 40 GHz.
  2. 2. The apparatus of claim 1, wherein the baseband unit generates the low phase noise baseband signal by direct digital frequency synthesis using a 16-bit wide low phase noise DAC chip based on the low phase noise clock signal.
  3. 3. The low-phase-noise signal generating device according to claim 2, wherein the baseband unit adopts a hardware architecture of 'high-performance fpga+high-speed DAC', receives signal parameters issued by an upper computer, and generates a baseband signal of low-phase-noise continuous wave.
  4. 4. A low phase noise signal generating apparatus according to claim 3, wherein the phase-locked frequency synthesis method specifically comprises: The reference unit generates a reference signal with extremely low phase noise by adopting a phase locking method by combining a 10MHz constant temperature crystal oscillator and a 100MHz voltage controlled crystal oscillator.
  5. 5. The apparatus of claim 4, wherein the low phase noise reference signal is a 1GHz signal, and the low phase noise local oscillator and clock unit multiplies, divides and mixes the frequency of the low phase noise reference signal based on the 1GHz signal and a10 GHz signal generated by a sapphire oscillator in the reference unit, and generates the dot frequency local oscillator signal with a frequency interval of 1 GHz.
  6. 6. The apparatus for generating a low phase noise signal as defined in claim 5, wherein the specific steps of obtaining the wideband fine stepping frequency reference signal are: the frequency reference unit fills the baseband signal generated by the baseband unit into the frequency interval of the local oscillation signal based on the direct frequency synthesis technology of frequency mixing, switching and filtering to obtain the broadband fine stepping frequency reference signal.
  7. 7. The apparatus of claim 6, wherein the output unit divides and multiplies the frequency based on the wideband fine stepping signal generated by the frequency reference unit to cover 200MHz-40GHz, and combines with the low frequency signal 10MHz-200MHz outputted by the baseband unit to generate the output signal with the frequency range of 10MHz-40 GHz.

Description

Low phase noise signal generating device Technical Field The invention belongs to the technical field of low-phase noise signal generation, and particularly relates to a low-phase noise signal generation device. Background Phase noise is a random phase fluctuation, so that the linear variation trend of the phase of a signal generator is distorted, and the phase noise is one of important performance parameters in the application fields of radar, radio communication, navigation positioning and the like, and is usually a limiting index of system performance. Conventional signal generation methods, such as single Phase Locked Loop (PLL) or direct digital frequency synthesis (DDS), often have difficulty in combining ultra-low phase noise, fine frequency stepping, and ultra-wideband coverage. For example, the pure PLL scheme is slow in frequency switching speed and complex in implementation of fine steps when implementing broadband coverage, while the pure DDS scheme is limited by clock frequency and slew rate of a digital chip, has limited output frequency and bandwidth, and severe degradation of phase noise performance in higher frequency bands. Therefore, a new signal generation technology and apparatus capable of comprehensively solving the challenges of broadband coverage, fine step tuning, ultra-low phase noise, and high environmental adaptability are needed. The foregoing is not necessarily a prior art, and falls within the technical scope of the inventors. Disclosure of Invention In order to solve the problems, the invention aims to provide a low-phase noise signal generating device, which perfectly combines the fine frequency resolution advantage of the DDS technology with the broadband and low-phase noise advantage of the analog direct frequency synthesis technology through an original three-stage architecture of 'baseband DDS fine stepping generation + local oscillator PLL large stepping phase locking + direct frequency synthesis filling'. Finally, the ultra-wide range of the output signal frequency coverage of 10MHz to 40GHz is realized, meanwhile, extremely fine frequency stepping is kept, and ultra-low phase noise indexes can be realized in a wide frequency band. In order to achieve the above objective, the present invention provides a low phase noise signal generating device, which includes a power module, a VPX main control board, a baseband unit, a reference unit, a local oscillator and clock unit, a frequency reference unit, and an output unit. The reference unit adopts a phase-locked frequency synthesis mode to realize low-phase noise reference signal generation. The local oscillator and clock unit generates a low phase noise clock signal and a local oscillator signal based on the low phase noise reference signal. The baseband unit generates a low phase noise baseband signal based on the low phase noise clock signal. The frequency reference unit expands the baseband signal with low phase noise to a certain bandwidth by utilizing a frequency mixing technology to obtain a broadband fine stepping frequency reference signal. The output unit is based on the broadband fine stepping frequency reference signal, and realizes the frequency expansion of low phase noise through frequency multiplication, frequency division and filtering treatment, and finally generates an output signal of 10MHz to 40 GHz. Preferably, the baseband unit generates the low-phase noise baseband signal by a direct digital frequency synthesis technology by using a 16-bit wide low-phase noise DAC chip based on the low-phase noise clock signal. Preferably, the baseband unit adopts a hardware architecture of 'high-performance FPGA+high-speed DAC', receives signal parameters issued by an upper computer, and generates a baseband signal of low-phase-noise continuous wave. Preferably, the phase-locked frequency synthesis mode specifically includes: The reference unit generates a reference signal with extremely low phase noise by adopting a phase locking method by combining a 10MHz constant temperature crystal oscillator and a 100MHz voltage controlled crystal oscillator. Preferably, the low phase noise reference signal is a 1GHz signal, and the local oscillator and clock unit with low phase noise generates a dot frequency local oscillator signal with a frequency interval of 1GHz based on the 1GHz signal and a 10GHz signal generated by a sapphire oscillator in the reference unit for frequency multiplication, frequency division and frequency mixing. Preferably, the specific steps for obtaining the wideband fine stepping frequency reference signal are as follows: the frequency reference unit fills the low-phase noise narrow-band fine stepping output signal generated by the baseband unit into the frequency interval of the local oscillation signal based on the direct frequency synthesis technology of mixing, switching and filtering to obtain the broadband fine stepping frequency reference signal. Preferably, the output unit performs frequency