Device for acquiring low phase noise frequency based on harmonic waves and electronic equipment
By replacing the traditional multi-crystal phase-locked loop with a single isothermal crystal harmonic multiplexing architecture, the output of low-phase-noise and high-stability frequency signals at multiple frequency points is realized, reducing costs and improving reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-04-10
AI Technical Summary
Traditional low-phase-noise, high-stability frequency signal acquisition schemes are costly and carry the risk of frequency loss of lock-in, requiring multiple temperature-controlled crystal oscillators and phase-locked loop circuits.
A single temperature-controlled crystal oscillator is used as the frequency source. Multiple low-phase-noise frequency signals are obtained through a harmonic amplifier unit and a frequency selector. The combination of harmonic amplification and filter is used to replace the multi-crystal phase-locked loop to achieve multi-frequency output of the frequency signal.
It reduces hardware costs, avoids the risk of loss of lockout caused by PLL bandwidth and frequency offset, and improves the reliability and stability of frequency signals.
Smart Images
Figure CN121841352A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of time frequency control, and in particular to a device for obtaining low phase noise frequency based on harmonics and electronic equipment. BACKGROUND
[0002] The device for time frequency control needs a frequency signal with low phase noise and high stability for use as a frequency source by the next level device. The traditional low phase noise and high stability is obtained by using a constant temperature crystal oscillator with low phase noise and high stability as a source to output. If a low phase noise frequency at a different frequency point is needed, a constant temperature crystal oscillator at the required frequency point is used. A phase-locked loop circuit is used to phase-lock two crystal oscillators with different frequencies.
[0003] However, the traditional scheme needs to increase one constant temperature crystal oscillator for each additional frequency output, and the price of a constant temperature crystal oscillator is as high as several thousand yuan per crystal oscillator. Therefore, the scheme needs a plurality of constant temperature crystal oscillators with different frequencies, and there is a risk of losing lock at each level of frequency due to the problems of loop bandwidth of each level of phase-locked loop circuit and frequency deviation before crystal oscillator stabilization. SUMMARY
[0004] The present application aims to overcome the deficiencies of the prior art and provide a device for obtaining low phase noise frequency based on harmonics and electronic equipment.
[0005] The purpose of the present application is achieved by the following technical solutions. In a first aspect, the present application discloses a device for obtaining low phase noise frequency based on harmonics, which comprises a constant temperature crystal oscillator serving as a single frequency source to provide a reference frequency signal. The output end of the constant temperature crystal oscillator is connected to a harmonic amplification unit. The harmonic amplification unit amplifies the reference frequency signal to generate a harmonic signal containing at least a target harmonic frequency. The harmonic amplification unit is connected with a first frequency selector. The first frequency selector selects a target harmonic frequency signal with the target harmonic frequency from the harmonic signal. The first frequency selector outputs the selected target harmonic frequency signal to a power adjustment unit. The power adjustment unit outputs the target harmonic frequency signal after power adjustment.
[0006] Further, the harmonic amplification unit comprises a first low noise amplifier. The input end of the first low noise amplifier is connected to the output end of the constant temperature crystal oscillator, and is used to amplify the reference frequency signal for the first time.
[0007] Further, the first power divider is further included; an input end of the first power divider is connected to an output end of the first low-noise amplifier and at least branches out a first branch, a second branch and a third branch, for dividing the amplified reference frequency signal into at least three branches; wherein the first branch and the second branch are respectively used for outputting the reference frequency signal, and the third branch is connected to the harmonic amplification unit to output the target harmonic frequency signal.
[0008] Further, the first band-pass filter and the second low-noise amplifier are further included; the first band-pass filter is connected to the first frequency selector to filter the target harmonic frequency signal, and an output end of the first band-pass filter is connected to the second low-noise amplifier to amplify the filtered target harmonic frequency signal.
[0009] Further, the third branch outputs the target harmonic frequency signal to a second power divider, and the second power divider at least branches out a first sub-branch and a second sub-branch; the first sub-branch is directly used as a first high-frequency output signal, and the second sub-branch is output to a second frequency selector to filter out a second high-frequency output signal; wherein the first high-frequency output signal and the second high-frequency output signal are different in frequency.
[0010] Further, the first sub-branch of the second power divider is sequentially connected to a first surface acoustic wave circuit and a power adjustment module to form and output the first high-frequency output signal; the second sub-branch is output to the second frequency selector and is further connected to a second band-pass filter, a third low-noise amplifier and a second surface acoustic wave circuit, and finally outputs the second high-frequency output signal through the power adjustment module.
[0011] Further, the first branch and the second branch are each connected to an LC filter circuit and a power adjustment module; the LC filter circuit is used for filtering out high-order harmonics and noise in the reference frequency signal, and the power adjustment module is used for adjusting the filtered reference frequency signal to a predetermined power value and then outputting.
[0012] In a second aspect, the application discloses an electronic device provided with the device for obtaining a low-phase-noise frequency based on harmonics.
[0013] The application has the following beneficial effects: through a single-crystal-oscillator harmonic multiplexing architecture, the traditional multi-crystal-oscillator phase-locked loop is replaced, the phase-locked noise accumulation and frequency traction problems are eliminated, the device realizes the output of a multi-frequency-point low-phase-noise high-stability frequency signal, and multiple constant-temperature crystal oscillators are not needed, so that the hardware cost can be greatly reduced, and because the same source frequency harmonics are output, the phase-locked loop circuit is not needed, so that there is no risk of losing lock caused by the phase-locked loop bandwidth and the initial frequency offset of the constant-temperature crystal oscillator, and the reliability is significantly improved. BRIEF DESCRIPTION OF DRAWINGS
[0014] Figure 1A simplified structural diagram of a device for obtaining a low-phase-noise frequency based on harmonics according to some embodiments of the present application; Figure 2 A schematic diagram of a principle of grading purification power supply for active devices at various levels of a frequency link according to some embodiments of the present application. DETAILED DESCRIPTION
[0015] The technical solutions of the present application will be described clearly and completely below in conjunction with embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0016] In conjunction with Figures 1-2 , the device for obtaining a low-phase-noise frequency based on harmonics and the electronic device according to the embodiments of the present application are understood.
[0017] The device for obtaining a low-phase-noise frequency based on harmonics according to the embodiments of the present application takes a constant-temperature crystal oscillator as a single frequency source and provides a reference frequency signal.
[0018] Subsequently, a constant-temperature crystal oscillator with low phase noise and high stability is taken as an example for illustration. The constant-temperature crystal oscillator outputs a pure 10MHz sine wave signal as an initial frequency source of the entire system. The output end of the constant-temperature crystal oscillator is connected to a harmonic amplification unit. The harmonic amplification unit amplifies the reference frequency signal to generate a harmonic signal containing at least a target harmonic frequency. The harmonic amplification unit includes a first low-noise amplifier. The input end of the first low-noise amplifier is connected to the output end of the constant-temperature crystal oscillator, and is configured to perform primary amplification on the reference frequency signal. The first low-noise amplifier performs power amplification on the 10MHz signal while minimizing the thermal noise and phase noise introduced by itself. The amplitude of the amplified signal is increased to meet the subsequent branching processing requirements.
[0019] Reference Figure 1The amplified signal is output to the first power divider, the input end of the first power divider is connected to the output end of the first low-noise amplifier, and at least the first branch, the second branch and the third branch are branched out, which are used to divide the amplified reference frequency signal into at least three independent branches. Among them, the first branch and the second branch are respectively used to output the reference frequency signal, and the third branch is connected to the harmonic amplification unit to output the target harmonic frequency signal. Specifically, the first branch and the second branch are respectively connected with an LC filter circuit and a power adjustment module, the LC filter circuit is used to filter out high-order harmonics and noise in the reference frequency signal, and the power adjustment module is used to adjust the filtered reference frequency signal to a predetermined power value and then output. The first branch connects the first LC filter circuit and the first pi-type power adjustment circuit as a power adjustment module, and the second branch connects the second LC filter circuit and the second pi-type power adjustment circuit as a power adjustment module. The LC filter circuit is composed of inductance and capacitance in a pi-type topology for filtering out high-order harmonics and external interference noise in the 10MHz signal; the filtered pure 10MHz signal enters the pi-type power adjustment circuit, which accurately adjusts the signal power to a predetermined value through an adjustable resistance network, the first branch is output to the 10M_OUT1 port, and the second branch is output to the 10M_OUT2 port, which is suitable for test equipment requiring dual-channel 10MHz reference.
[0020] The third branch is used for harmonic extraction and is directly fed into the first frequency selector. In this example, a 100MHz SAW filter is used as an example. The first frequency selector selects the target harmonic frequency signal with the target harmonic frequency from the harmonic signal. The 100MHz SAW filter receives the 10MHz base frequency signal (containing multiple harmonic components) of the third branch of the power divider, and the internal surface acoustic wave resonance structure only allows the 100MHz±1MHz frequency band to pass through, and suppresses other frequency points, such as 90MHz and 110MHz spurs.
[0021] In addition, considering that the SAW filter is easy to introduce phase jitter under small signal, therefore, the input signal power needs to be large enough to make the acoustic wave conversion process more stable and reduce noise deterioration.
[0022] Therefore, in some embodiments, a low phase noise and high stability frequency source (such as 100MHz) is used to adopt power super purification technology, that is, multi-stage LDO and filtering suppression, acoustic surface filtering power overdrive to reduce stability loss, through step-by-step harmonic power amplification and final filtering output, etc. way, realize to obtain rich high stability, low phase noise frequency output from a single frequency source. For example, high stable and low noise frequencies such as 200MHz and 500MHz can be obtained from a 100MHz frequency source. Similarly, this method is suitable for low phase noise harmonic acquisition of various frequency sources. The first frequency selector outputs the selected target harmonic frequency signal to the power adjustment unit.
[0023] Continue to refer toFigure 1 The third branch is explained as follows. The output end of the 100MHz SAW filter is connected to the first band-pass filter and the second low-noise amplifier in sequence. The first band-pass filter is connected to the first frequency selector to filter the target harmonic frequency signal and filter out the new spurs and residual base frequency leakage generated by the amplifier. The output end of the first band-pass filter is connected to the second low-noise amplifier to amplify the filtered target harmonic frequency signal, increase the power of the 100MHz signal, and control the noise at the same time. The amplified signal is then divided into two paths by the second power divider: the second power divider at least branches out the first sub-branch and the second sub-branch.
[0024] The first sub-branch directly serves as the first high-frequency output signal. Specifically, the first sub-branch of the second power divider is connected to the first surface acoustic circuit and the power adjustment module in sequence to form and output the first high-frequency output signal, for example, output from the 100M_OUT1 port, for use by external devices. The second sub-branch is output to the second frequency selector to screen out the second high-frequency output signal, wherein the first high-frequency output signal and the second high-frequency output signal have different frequencies.
[0025] For the second sub-branch, it is output to the second frequency selector, i.e., the XXM SAW filter performs frequency selection (narrow-band surface acoustic wave filter, center frequency XXM). Here, “XXM” represents any frequency that needs to be output.
[0026] In this way, when the input power needs to be close to the upper limit of the SAW filter, the noise suppression effect can be maximized. After frequency selection, the signal enters the second band-pass filter (center frequency XXM) dedicated to XXM as a second frequency selection link to filter out the adjacent frequency noise introduced by the SAW filter. Then, the signal is amplified for the second time by the third low-noise amplifier. Next, the signal is further frequency-selected by the second surface acoustic circuit, and finally the power is adjusted by the power adjustment module (such as the fourth π-type power adjustment circuit) to be output from the XXM_OUT2 port to form the second high-frequency output signal.
[0027] Thus, before the frequency selection of the surface acoustic filter, the original frequency is amplified first, and the nonlinearity is used to make the power of the required harmonic frequency point as large as possible to reduce the phase noise loss when the rear stage is filtered and selected again; the amplified frequency enters the first frequency selection, at which time the narrow-band surface acoustic wave filter is selected to select the required frequency signal, and the power entering the surface acoustic wave needs to be large enough to reduce the loss of phase noise and stability; the frequency signal after frequency selection is amplified to the required power for the second time, and finally output after the second frequency selection and filtering by the surface acoustic filter. The input power of the second frequency selection and filtering needs to be close to the upper limit of the power input of the surface acoustic filter, and the large power input can reduce the loss of phase noise and frequency stability, and finally the adaptive power is adjusted by the backoff to be output externally.
[0028] It can be understood that, by the single crystal vibration harmonic multiplexing architecture, the traditional multi-crystal oscillator phase-locked loop is replaced, the phase-locked noise accumulation and frequency traction problems are eliminated, the device realizes the output of a multi-frequency low phase noise high stability frequency signal, and without multiple constant temperature crystal oscillators, the hardware cost can be greatly reduced, and because the same source frequency harmonic output is adopted, the phase-locked loop circuit is not needed, and therefore there is no risk of losing lock caused by the phase-locked loop bandwidth and the initial frequency offset of the constant temperature crystal oscillator, thereby the reliability is significantly improved.
[0029] In addition, in the embodiment of the present application, the power supply of the active devices at each level of the frequency link is purified at each level, thereby obtaining the best link noise.
[0030] Specifically, referring to Figure 2 It is understood that the DCDC main power supply is used to purify the large current LDO at a first level, and to supply power to the OCXO constant temperature crystal oscillator which requires large current and low noise ripple. The power supply after the first purification is purified by a second small current LDO at a second level, and the small current LDO has a high PSRR power supply rejection ratio. The power supply after the second purification is used to supply power to the OCXO operational amplifier link to meet the low noise performance of the operational amplifier. The power supply after the second purification is further purified by a third bandgap reference source. The bandgap reference source has the characteristics of ultra-low noise and temperature drift suppression, but its power supply band load capacity is weak, and is only suitable for the power supply of small current devices such as LNA in the frequency link.
[0031] According to the electronic device of the embodiment of the present application, the device for obtaining low phase noise frequency based on harmonics in the above embodiment is provided.
[0032] The above only describes the preferred embodiments of the present application, and it should be understood that the present application is not limited to the forms disclosed herein, and should not be considered as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concepts described herein by the above teachings or related art or knowledge. Any modification and change made by those skilled in the art without departing from the spirit and scope of the present application shall be within the protection scope of the claims of the present application.
Claims
1. A device for obtaining low phase noise frequencies based on harmonics, characterized in that, It includes a temperature-controlled crystal oscillator that provides a reference frequency signal as a single frequency source, the output of which is connected to a harmonic amplification unit that amplifies the reference frequency signal to generate a harmonic signal that contains at least the target harmonic frequency. The harmonic amplification unit is connected to a first frequency selector, which filters out a target harmonic frequency signal with a target harmonic frequency from the harmonic signal. The first frequency selector outputs the filtered target harmonic frequency signal to the power adjustment unit, which adjusts the power of the target harmonic frequency signal before outputting it.
2. The device for obtaining low phase noise frequencies based on harmonics according to claim 1, characterized in that, The harmonic amplification unit includes a first low-noise amplifier, the input of which is connected to the output of the thermostatic crystal oscillator, for initial amplification of the reference frequency signal.
3. The apparatus for obtaining low phase noise frequencies based on harmonics according to claim 1 or 2, characterized in that, It also includes the first power divider; The input terminal of the first power divider is connected to the output terminal of the first low-noise amplifier and branches out at least a first branch, a second branch, and a third branch, for dividing the amplified reference frequency signal into at least three branches; The first branch and the second branch are respectively used to output the reference frequency signal, and the third branch is connected to the harmonic amplification unit to output the target harmonic frequency signal.
4. The device for obtaining low phase noise frequency based on harmonics according to claim 3, characterized in that, It also includes a first bandpass filter and a second low-noise amplifier; The first bandpass filter is connected to the first frequency selector to filter the target harmonic frequency signal, and its output is connected to the second low-noise amplifier to amplify the filtered target harmonic frequency signal.
5. The device for obtaining low phase noise frequency based on harmonics according to claim 4, characterized in that, The third branch outputs the target harmonic frequency signal to the second power divider, and the second power divider branches out at least the first sub-branch and the second sub-branch. The first sub-branch is directly used as the first high-frequency output signal, and the second sub-branch is output to the second frequency selector to filter out the second high-frequency output signal. The first high-frequency output signal and the second high-frequency output signal have different frequencies.
6. The device for obtaining low phase noise frequency based on harmonics according to claim 5, characterized in that, The first sub-branch of the second power divider is connected in sequence to the first surface acoustic wave circuit and the power adjustment module to form and output the first high-frequency output signal; The second sub-branch outputs to the second frequency selector and continues to be connected to the second bandpass filter, the third low-noise amplifier, and the second surface acoustic wave (SAW) circuit. Finally, the second high-frequency output signal is output through the power adjustment module.
7. The device for obtaining low phase noise frequency based on harmonics according to claim 3, characterized in that, The first branch and the second branch are each connected to an LC filter circuit and a power adjustment module. The LC filter circuit is used to filter out high-order harmonics and noise in the reference frequency signal, and the power adjustment module is used to adjust the filtered reference frequency signal to a predetermined power value before outputting it.
8. An electronic device, characterized in that, The device for obtaining low phase noise frequency based on harmonics as described in any one of claims 1-7 is provided.