Multi-channel ultra-low phase noise frequency synthesis device without phase synchronization

Abstract

The multi-channel low-phase-noise frequency synthesis device overcomes the defects in the existing multi-channel low-phase-noise frequency source synthesis technology, does not need to perform phase synchronization on multi-channel signals, can break through the theoretical limitation of the traditional phase noise 20 LogN through multi-channel signal synthesis, and has the advantages of being simple in structure and convenient to operate. Multiple paths of coherent dot frequency signals are generated through a plurality of phase-locked crystal oscillators locked on a reference crystal oscillator and a frequency multiplier, and the dot frequency signals are phase noise coherent in loop bandwidths of the phase-locked crystal oscillators and do not have phase noise coherent outside the loop bandwidths. And then the dot frequency signals are superposed step by step through a plurality of frequency mixers to finally obtain a required output signal. In the signal superposition process, multiple paths of signals do not need to be synthesized through a power synthesizer after phase synchronization is kept through a complex device, and the system architecture of the ultra-low phase noise frequency source can be greatly simplified.

Description

Technical Field

[0001] The invention belongs to the technical field of signal processing, and in particular relates to a multi-channel ultra-low phase noise frequency synthesis device without phase synchronization. Background Art

[0002] The frequency source is both the excitation signal source of the transmitting channel of the modern electronic system and the local oscillator of the receiving channel. The performance of the frequency source directly affects the final performance of the electronic system. In order to achieve a large dynamic range of the receiving system and reduce the system background noise, it is urgent to design an ultra-low phase noise frequency source to ensure or expand the dynamic range of the receiving system to ensure the detection sensitivity of the system. Summary of the invention

[0003] The present invention overcomes the shortcomings of the existing multi-channel low phase noise frequency source synthesis technology, and proposes a multi-channel low phase noise frequency synthesis device that does not require phase synchronization of multi-channel signals. Through the synthesis of multi-channel signals, the theoretical limit of the traditional phase noise of 20LogN can be broken through. Multiple phase-locked crystal oscillators and frequency multipliers locked on a reference crystal oscillator generate multi-channel coherent point frequency signals. These point frequency signals are phase noise coherent within the loop bandwidth of the phase-locked crystal oscillator, and the phase noise is incoherent outside the loop bandwidth. Then, these point frequency signals are superimposed step by step through multiple mixers to finally obtain the required output signal. In the process of signal superposition, there is no need to keep the phase synchronization of the multi-channel signals through a complex device and then synthesize them through a power synthesizer, which can greatly simplify the system architecture of the ultra-low phase noise frequency source.

[0004] Because the noise signal of each signal within the loop bandwidth is coherent with the noise of the reference crystal oscillator output signal, they will be superimposed in voltage, while the phase noise outside the loop bandwidth is incoherent with the reference crystal oscillator output signal, and the output noise will be superimposed in power. Therefore, each time the phase noise is superimposed, the deterioration of the phase noise will be 3dB less than the traditional frequency doubling scheme, so that the final output signal can obtain ultra-low phase noise.

[0005] The specific structure of the multi-channel ultra-low phase noise frequency synthesizer without phase synchronization of the present invention includes a reference crystal oscillator, a phase-locked crystal oscillator, a frequency multiplier, a mixer, a multi-stage filter and an amplifier. The reference crystal oscillator generates multiple reference signals which are respectively input into the corresponding phase-locked crystal oscillator. The signal output by the phase-locked crystal oscillator generates multiple frequency signals of the same or different frequencies through the frequency multiplier and sends them to the corresponding mixer. Multiple mixers superimpose and output these frequency signals step by step. After passing through the multi-stage filter and amplifier in turn, the ultra-low phase noise frequency signal is finally obtained.

[0006] The beneficial effects of the present invention are

[0007] 1. The system architecture is simple and cost-effective. 2. The circuit is mature, stable and reliable, and has good environmental adaptability. 3. The architecture is flexible, the output frequency is variable, and it can adapt to the needs of various frequency bands. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 The figure is a schematic diagram of the system structure of the present invention.

[0009] Among them, 1-reference crystal oscillator, 2-phase-locked crystal oscillator, 3-frequency multiplier, 4-mixer, 5-multi-stage filter, 6-amplifier. DETAILED DESCRIPTION

[0010] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0011] Figure 1 In the invention, a reference signal generated by a reference crystal oscillator (1) is input to a phase-locked crystal oscillator (2), and a plurality of frequency signals of the same or different frequencies are generated by a frequency multiplier (3) and sent to a mixer (4). The signals output by the plurality of mixers are passed through a multi-stage filter (5) and an amplifier (6) to finally obtain an ultra-low phase noise frequency signal.

[0012] The present invention utilizes the principle of non-correlated noise cancellation and the phase-insensitive characteristic of signal accumulation achieved by mixing, which can effectively reduce the phase noise of the frequency source, and can improve the phase noise of the traditional frequency source by 10LogN dB. At the same time, it can greatly simplify the architecture of the multi-channel synthetic frequency source system and reduce the system cost. And by changing the multiplication number of the frequency multiplier, the present invention supports the step-by-step cascading of point frequency sources of different frequencies to achieve a wider output frequency range. The present invention is suitable for various radars and electronic equipment that require ultra-low phase noise.

[0013] The present invention is not limited to the above specific implementations, and the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made to the above implementations based on the technical essence of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-channel ultra-low phase noise frequency synthesis device without phase synchronization, characterized in that: Including reference crystal oscillators, phase-locked crystal oscillators, frequency multipliers, mixers, multi-stage filters and amplifiers; The reference crystal oscillator generates multiple reference signals which are respectively input into the corresponding phase-locked crystal oscillator. The signal output by the phase-locked crystal oscillator generates multiple frequency signals of the same or different frequencies through a frequency multiplier and sends them to the corresponding mixer. Multiple mixers superimpose and output these frequency signals step by step. After passing through multiple stages of filters and amplifiers in turn, an ultra-low phase noise frequency signal is finally obtained.

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