CN117060920A - Filter circuit for inhibiting phase discrimination leakage spurious - Google Patents
Filter circuit for inhibiting phase discrimination leakage spurious Download PDFInfo
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- CN117060920A CN117060920A CN202310868918.7A CN202310868918A CN117060920A CN 117060920 A CN117060920 A CN 117060920A CN 202310868918 A CN202310868918 A CN 202310868918A CN 117060920 A CN117060920 A CN 117060920A
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- 230000002401 inhibitory effect Effects 0.000 title claims abstract description 6
- 239000003990 capacitor Substances 0.000 claims description 14
- 230000001629 suppression Effects 0.000 claims description 8
- 238000001914 filtration Methods 0.000 claims description 6
- 230000002708 enhancing effect Effects 0.000 claims description 5
- 230000005764 inhibitory process Effects 0.000 abstract description 9
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 238000003786 synthesis reaction Methods 0.000 abstract description 2
- 238000001514 detection method Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000000452 restraining effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L7/00—Automatic control of frequency or phase; Synchronisation
- H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
- H03L7/08—Details of the phase-locked loop
- H03L7/085—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal
- H03L7/093—Details of the phase-locked loop concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal using special filtering or amplification characteristics in the loop
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/06—Frequency selective two-port networks including resistors
Abstract
The invention belongs to the technical field of phase-locked frequency synthesis, and particularly relates to a filter circuit for inhibiting phase discrimination leakage spurious. For suppressing phase discrimination leakage of the phase discriminator; one end of the loop filter circuit is connected with the phase discriminator, and the other end of the loop filter circuit is connected with the voltage-controlled oscillator; the invention is provided with the resonance circuit connected in series in the passive loop filter circuit, is used for trapping waves with the same or similar phase discrimination frequency, enhances the inhibition capability of the loop filter circuit to phase discrimination leakage, and can solve the problem of phase discrimination leakage strays of the phase-locked loop when the phase discrimination frequency is smaller.
Description
Technical Field
The invention belongs to the technical field of phase-locked frequency synthesis, and particularly relates to a filter circuit for inhibiting phase discrimination leakage spurious.
Background
The basic theory of phase-locking technology is frequency synchronization or phase locking, which is characterized in that the generated intrinsic signal has the same frequency as the other input signal of the detector, and the phase difference is constant, i.e. if the phase between the two signals is stabilized, the frequencies of the two oscillators are necessarily equal; if the phase difference of the two signals is stable, the frequencies of the two signals must be equal. The phase locking technology is widely applied to the aerospace direction, including the fields of speed measurement and orbit determination of an orbit satellite, deep space detection, communication, radar and the like, and provides a frequency hopping local oscillation signal for a radar receiving and transmitting system. The classical phase-locked loop circuit is shown in fig. 1 and consists of a phase detector, a loop filter circuit (including an active loop filter circuit or a passive loop filter circuit) and a Voltage Controlled Oscillator (VCO).
The loop filter circuit not only serves as a low-pass filter to filter out high-frequency components, but also affects important parameters of a loop, such as phase noise, loop stability, locking time and the like, so that the design of the loop filter is also important in order to obtain a phase-locked loop system with good performance. In general, the suppression of phase discrimination leakage spurs by a loop filter circuit in a phase-locked loop circuit is related to the phase-locked loop bandwidth, and the wider the phase-locked loop bandwidth is, the weaker the suppression capability is, and vice versa. In the current domestic phase discriminator fractional working mode, fractional spurious is uncontrollable, an integer working mode is preferably selected, in the application of small step frequency hopping, the phase discrimination frequency of the phase discriminator in the integer working mode is equal to the frequency hopping step, and the spurious spectrum leaked by phase discrimination deviates from a main signal more closely, so that the traditional loop filter circuit has weaker capability of inhibiting the spurious leaked by phase discrimination, and meanwhile, in the occasion with strict requirements on frequency hopping time, the loop bandwidth of the phase-locked loop cannot be narrowed without limit. Therefore, the conventional loop filter circuit can not effectively solve the problem of phase discrimination leakage spurious when the phase discrimination frequency is smaller.
Disclosure of Invention
In view of this, the invention provides a filter circuit for suppressing phase discrimination leakage spurious, which can solve the problem of phase discrimination leakage spurious of a phase-locked loop when the phase discrimination frequency is smaller.
In order to achieve the technical purpose, the invention adopts the following specific technical scheme:
a filter circuit for restraining phase discrimination leakage stray is used for restraining phase discrimination leakage of a phase discriminator; one end of the filter circuit is connected with the phase discriminator, and the other end of the filter circuit is connected with the voltage-controlled oscillator;
the filter circuit includes:
the loop filter circuit is a passive loop filter circuit;
and the resonance circuit is connected in series in the passive loop filter circuit and is used for trapping waves with the same or similar frequency as the phase discrimination frequency and enhancing the inhibition capability of the loop filter circuit on the phase discrimination leakage.
Further, under the condition that the frequency hopping time index and the stability of the circuit are met, the bandwidth of the loop filter circuit cannot be continuously compressed, and when the loop filter circuit cannot meet the inhibition degree index of phase discrimination leakage, the resonant circuit is used for enhancing the inhibition degree index.
Further, the number of the resonant circuits is not less than one group;
the resonant circuit sets a corresponding resonant frequency according to the frequency of phase discrimination leakage;
further, when the number of the resonant circuits is greater than one group, the resonant frequencies of the resonant circuits are the same or different.
Further, the resonant circuit comprises an inductor and at least two capacitors which are connected in parallel;
the mode of setting the corresponding frequency for the resonant circuit according to the frequency of phase discrimination leakage is as follows: according to the parallel resonance formula of inductance and capacitanceAnd selecting the inductance corresponding to the inductance value and the capacitance corresponding to the capacitance value.
Further, in the resonant circuit, the capacitor with a larger capacitance value is used for enabling the resonant circuit to be roughly matched to the frequency of the phase discrimination leakage, and the other capacitors with smaller capacitance values are used for enabling the resonant circuit to be finely matched step by step to the frequency of the phase discrimination leakage.
Further, the number of the capacitors in the resonant circuit is two.
By adopting the technical scheme, the invention has the following beneficial effects:
compared with the traditional loop filter circuit, the phase-discrimination leakage spurious suppression of the phase-locked loop is improved by embedding the parallel resonant circuit in the active loop filter circuit or the passive loop filter circuit under the same loop bandwidth. The phase-locked loop circuit has the advantages of strong universality, simple structure, easy processing and realization and mass production, and can be widely applied to phase-locked loop circuits.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.
Fig. 1 is a classical phase-locked loop circuit;
FIG. 2 is a conventional loop filtering model;
FIG. 3 is a schematic diagram of a filter circuit for suppressing phase-discrimination leakage spurs in accordance with an embodiment of the present invention;
FIG. 4 is a graph of the output spectrum of a conventional loop filter circuit;
fig. 5 is an output spectrum diagram of a filter circuit according to an embodiment of the invention.
Detailed Description
Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.
Other advantages and effects of the present disclosure will become readily apparent to those skilled in the art from the following disclosure, which describes embodiments of the present disclosure by way of specific examples. It will be apparent that the described embodiments are merely some, but not all embodiments of the present disclosure. The disclosure may be embodied or practiced in other different specific embodiments, and details within the subject specification may be modified or changed from various points of view and applications without departing from the spirit of the disclosure. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict. All other embodiments, which can be made by one of ordinary skill in the art without inventive effort, based on the embodiments in this disclosure are intended to be within the scope of this disclosure.
It is noted that various aspects of the embodiments are described below within the scope of the following claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present disclosure, one skilled in the art will appreciate that one aspect described herein may be implemented independently of any other aspect, and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. In addition, such apparatus may be implemented and/or such methods practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.
It should also be noted that the illustrations provided in the following embodiments merely illustrate the basic concepts of the disclosure by way of illustration, and only the components related to the disclosure are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated.
In addition, in the following description, specific details are provided in order to provide a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects may be practiced without these specific details.
In one embodiment of the present invention, a filter circuit for suppressing phase detection leakage spurious is provided, for suppressing phase detection leakage of a phase detector; one end of the filter circuit is connected with the phase discriminator, and the other end of the filter circuit is connected with the voltage-controlled oscillator;
as shown in fig. 3, the filter circuit includes:
the loop filter circuit is a passive loop filter circuit;
and the resonance circuit is connected in series in the passive loop filter circuit and is used for trapping waves with the same or similar frequency as the phase discrimination frequency and enhancing the inhibition capability of the loop filter circuit on the phase discrimination leakage.
In this embodiment, under the condition that the frequency hopping time index and the stability of the circuit are satisfied, the bandwidth of the loop filter circuit cannot be continuously compressed, and when the loop filter circuit cannot satisfy the inhibition degree index of phase discrimination leakage, the resonant circuit is used for enhancing the inhibition degree index.
In this embodiment, the number of the resonance circuits is not less than one group;
the resonant circuit sets a corresponding resonant frequency according to the frequency of phase discrimination leakage;
in this embodiment, when the number of the resonance circuits is greater than one group, the resonance frequencies of the resonance circuits are the same or different.
In this embodiment, the resonant circuit includes an inductance in parallel and at least two capacitances;
the mode of setting the corresponding frequency for the resonant circuit according to the frequency of phase discrimination leakage is as follows: according to the parallel resonance formula of inductance and capacitanceAnd selecting the inductance corresponding to the inductance value and the capacitance corresponding to the capacitance value.
In this embodiment, in the resonant circuit, the capacitor with a larger capacitance value is used to enable the resonant circuit to be roughly matched to the frequency of the phase-discrimination leakage, and the other capacitors with smaller capacitance values are used to enable the resonant circuit to be finely matched to the frequency of the phase-discrimination leakage step by step.
The resonant circuit has the function of notch, the resonant frequency of the resonant circuit is an integral multiple of the phase discrimination frequency, and the capacitance value of the capacitor is limited, so that the capacitor of the embodiment adopts two parallel connection modes to realize more accurate frequency inhibition in order to improve the phase discrimination leakage inhibition effect of the resonant circuit. The following further details of the present invention are described using a single loop phase locked loop in Ku band as an example:
the phase discriminator is GM4704B of the core technology, the phase discriminator adopts 100MHz reference signal as reference signal input, the working mode adopts integer mode, the loop filter circuit is a passive loop filter circuit as shown in figure 2, the VCO (voltage controlled oscillator) adopts a broadband segmented VCO chip SIV019SP4 of a Shi core semiconductor, the VCO works at 9 th segment, the output frequency is 14000 MHz-15000 MHz of Ku wave band, the frequency steps by 10MHz, in addition, the power supply module provides +3.3V for supplying power to the phase discriminator, and +3.3V and +5V for supplying power to the voltage controlled oscillator. And transmitting three sets of SPI control DATA of LE, CLK and DATA to the phase detector through a singlechip program, and controlling the digital phase detector to carry out R pre-frequency division and feedback N frequency division. According to the characteristic that the output frequency steps by 10MHz, the phase-locked loop adopts 10MHz phase discrimination, and the resistance capacitance value of the passive loop filter module is as follows: c1 =390pf, r1=220Ω, c2=68nf, r2=33Ω, c3=120pf, r3=33Ω, c4=1800 pF. Under the value of the loop, the spurious leakage of the phase discrimination of the test loop is restrained to 60dBc by + -10 MHz, and 75dBc by + -20 MHz, and the spectrometer test is shown in figure 4. Then, a loop filter circuit for suppressing phase discrimination leakage spurious of the low phase discrimination frequency phase-locked loop shown in fig. 3 is adopted, on the basis of the passive loop filter circuit of fig. 3, two resonant circuits are a first resonant circuit and a second resonant circuit respectively, wherein the first resonant circuit comprises an inductor L1, a capacitor C5 and a capacitor C6, and the second resonant circuit comprises an inductor L2, a capacitor C7 and a capacitor C8. The values of the resistor, the inductor and the capacitor are as follows: c1 =390 pF, r1=220 Ω, c2=68 nf, r2=33 Ω, c3=120 pF, r3=33 Ω, c4=180 pF, r4=33 Ω, l1=5.6uh, c4=39 pF, c5=6.8pf, l2=1.5uh, c4=39 pF, c5=3.9 pF. Under the value of the loop, the spurious detection leakage of the loop is tested, the spurious suppression of +/-10 MHz is 80dBc, the spurious suppression of +/-20 MHz is better than 95dBc, and the spectrometer test is shown in figure 5. The phase-discrimination leakage spurious value (as shown in fig. 4) is optimized by 20dB compared to the conventional loop filter circuit.
The foregoing is merely specific embodiments of the disclosure, but the protection scope of the disclosure is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the disclosure are intended to be covered by the protection scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.
Claims (7)
1. The filter circuit is characterized by being used for inhibiting phase discrimination leakage of the phase discriminator; one end of the filter circuit is connected with the phase discriminator, and the other end of the filter circuit is connected with the voltage-controlled oscillator;
the filter circuit includes:
the loop filter circuit is a passive loop filter circuit;
and the resonance circuit is connected in series in the passive loop filter circuit and is used for trapping waves with the same or similar frequency as the phase discrimination frequency and enhancing the suppression capability of the loop filter circuit on the phase discrimination leakage.
2. The filtering circuit for suppressing phase-discrimination leakage spurs of claim 1, wherein said resonant circuit is configured to enhance a suppression degree indicator for phase-discrimination leakage when a bandwidth of the loop filtering circuit is unable to be continuously compressed under conditions that satisfy a frequency hopping time indicator and a stability of the circuit, and the loop filtering circuit is unable to satisfy the suppression degree indicator for phase-discrimination leakage.
3. The filter circuit for suppressing phase-discrimination leakage spurs according to claim 2, wherein the number of said resonant circuits is not less than one group;
the resonant circuit sets a corresponding resonant frequency according to the frequency of the phase discrimination leakage.
4. A filter circuit for suppressing phase-discrimination leakage spurs as claimed in claim 3, wherein the resonant frequencies of each of said resonant circuits are the same or different when the number of said resonant circuits is greater than one group.
5. The filtering circuit for suppressing phase-discrimination leakage spurs of claim 4, wherein said resonant circuit includes an inductance in parallel and at least two capacitances;
the mode of setting the corresponding frequency for the resonant circuit according to the frequency of phase discrimination leakage is as follows: according to the parallel resonance formula of inductance and capacitanceAnd selecting the inductance corresponding to the inductance value and the capacitance corresponding to the capacitance value.
6. The filtering circuit of claim 5, wherein in the resonant circuit, a larger capacitance is used to roughly match the resonant circuit to the frequency of the phase discrimination leakage, and the remaining smaller capacitance is used to finely match the resonant circuit to the frequency of the phase discrimination leakage step by step.
7. The filter circuit of claim 6, wherein the number of capacitors in the resonant circuit is two.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310868918.7A CN117060920A (en) | 2023-07-13 | 2023-07-13 | Filter circuit for inhibiting phase discrimination leakage spurious |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310868918.7A CN117060920A (en) | 2023-07-13 | 2023-07-13 | Filter circuit for inhibiting phase discrimination leakage spurious |
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| Publication Number | Publication Date |
|---|---|
| CN117060920A true CN117060920A (en) | 2023-11-14 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310868918.7A Pending CN117060920A (en) | 2023-07-13 | 2023-07-13 | Filter circuit for inhibiting phase discrimination leakage spurious |
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| CN (1) | CN117060920A (en) |
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2023
- 2023-07-13 CN CN202310868918.7A patent/CN117060920A/en active Pending
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