High-resolution low-spurious low-phase-noise variable reference signal synthesizer for frequency synthesis
By constructing a frequency synthesizer containing a phase-locked loop chip, the problems of high power consumption and poor spurious performance of traditional frequency synthesizers are solved, realizing low power consumption, low spurious performance, and high resolution signal synthesis, which is suitable for fields such as instrumentation, communication, navigation, and radar.
Patent Information
- Application Number
- CN202423088770.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-14
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-12-14
AI Technical Summary
Traditional frequency synthesizers suffer from high power consumption, high clock frequency, and poor spurious performance, making it difficult to meet the requirements of wide bandwidth and small step size.
A frequency synthesizer composed of components such as a temperature-controlled crystal oscillator, power divider, operational amplifier, step transistor frequency multiplier, phase-locked loop (PLL) chip, low-pass filter, and mixer is used to synthesize a variable reference signal by replacing the DDS with a PLL chip. The low power consumption and low spurious characteristics of the PLL chip are utilized, combined with multi-stage filters, to achieve high-resolution and low-phase-noise signal synthesis.
It achieves low-power, low-spurious, and high-resolution frequency synthesis, simplifies circuit design, reduces costs and technical risks, shortens development cycles, and is applicable to fields such as instrumentation, communication, navigation, and radar.
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Figure CN223613315U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a signal synthesizer, specifically relates to a high resolution low stray low phase noise variable reference signal synthesizer for frequency synthesis. BACKGROUND
[0002] Low power consumption, low phase noise, low stray and high resolution frequency synthesizer can produce million of frequencies with same stability and accuracy with a high stability and accuracy reference frequency, is widely used in instrument, communication, navigation, radar, electronic warfare and other fields, is praised as the "heart" of electronic equipment, has important influence to the performance of electronic information equipment. With the need of communication and military development, signal reconnaissance frequency band is expanding, and it is required to develop wideband, small step, low stray microwave frequency synthesizer.
[0003] The traditional synthesizer uses DDS, although having good frequency resolution, but power consumption is big, clock frequency is high. Fractional frequency division phase-locked loop has the characteristics of low cost, simple circuit, high frequency resolution, but high frequency resolution and integer boundary stray are a pair of contradictory technical requirements, in order to obtain high frequency resolution, there will be poor stray performance. UTILITY MODEL CONTENT
[0004] Therefore, the utility model provides a high resolution low stray low phase noise variable reference signal synthesizer for frequency synthesis to solve the problems of high power consumption, high clock frequency and poor stray performance in the prior art.
[0005] In order to realize the above object, the utility model provides the following technical scheme: a high resolution low stray low phase noise variable reference signal synthesizer for frequency synthesis, comprising a constant temperature crystal oscillator, a power divider, an operational amplifier, a step tube frequency multiplier, a first three-stage filter amplifier, a phase-locked loop chip, a low pass filter, a frequency mixer and a second three-stage filter amplifier.
[0006] The output end of the constant temperature crystal oscillator is connected with the input end of the power divider, the first output end of the power divider is electrically connected with the input end of the operational amplifier, and the second output end of the power divider is electrically connected with the input pin of the phase-locked loop chip.
[0007] The output end of the operational amplifier is electrically connected with the input end of the step tube frequency multiplier, the output end of the step tube frequency multiplier is electrically connected with the input end of the first three-stage filter amplifier, and the output end of the first three-stage filter amplifier is electrically connected with the local oscillator port of the frequency mixer.
[0008] The output pin of the phase-locked loop chip is electrically connected with the input end of the low-pass filter, the output end of the low-pass filter is electrically connected with the local oscillator port of the frequency mixer, and the intermediate frequency port of the frequency mixer is electrically connected with the input end of the second tertiary filter amplifier.
[0009] As a preferred scheme of the high-resolution low-spur low-phase-noise variable reference signal synthesizer for frequency synthesis, the thermostat crystal oscillator is used to provide a fixed reference signal.
[0010] The power divider is used to divide the fixed reference signal provided by the thermostat crystal oscillator into two paths.
[0011] As a preferred scheme of the high-resolution low-spur low-phase-noise variable reference signal synthesizer for frequency synthesis, the operational amplifier is used to amplify the signal distributed by the power divider, and the step-tube frequency multiplier is used to process the signal amplified by the operational amplifier into a comb spectrum signal containing high-order harmonics.
[0012] As a preferred scheme of the high-resolution low-spur low-phase-noise variable reference signal synthesizer for frequency synthesis, the first tertiary filter amplifier is used to amplify the comb spectrum signal containing high-order harmonics processed by the step-tube frequency multiplier, so as to select a fixed high-order harmonic signal as the local oscillator signal of the frequency mixer.
[0013] As a preferred scheme of the high-resolution low-spur low-phase-noise variable reference signal synthesizer for frequency synthesis, the phase-locked loop chip is used to frequency-division the signal distributed by the power divider to obtain a 50MHz-100MHz high-resolution variable reference signal.
[0014] As a preferred scheme of the high-resolution low-spur low-phase-noise variable reference signal synthesizer for frequency synthesis, the low-pass filter is used to low-pass filter the 50MHz-100MHz high-resolution variable reference signal output by the phase-locked loop chip, so as to up-mix the signal as the intermediate frequency input signal of the frequency mixer.
[0015] As a preferred scheme of the high-resolution low-spur low-phase-noise variable reference signal synthesizer for frequency synthesis, the second tertiary filter amplifier is used to select a variable reference signal by performing tertiary filter amplification on the up-mixing output signal of the frequency mixer.
[0016] The utility model has the following advantages: the phase-locked loop chip replaces DDS to realize the synthesis of variable reference signal, the area, cost and power consumption are obviously lower than DDS, although the frequency resolution index is lower than DDS, but most application requirements can be met, under the condition that the frequency resolution meets the requirement, the low cost, simple circuit design is used to realize the wide frequency range, high resolution, low stray and low phase noise variable reference signal, the low power consumption and volume provide the powerful support for the miniaturization design of frequency source, can simplify the complexity of frequency source synthesis, improve the reliability of product, effectively reduce the technical risk of project, shorten the development cycle of project, reduce the technical requirement of control circuit, simplify the complexity of microwave division system, thereby reduce the cost of overall system. BRIEF DESCRIPTION OF DRAWINGS
[0017] In order to more clearly illustrate the embodiment of the utility model or the technical scheme in the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description. Obviously, the drawings in the following description are only exemplary, and those skilled in the art can also obtain other implementation drawings according to the provided drawings without creating labor.
[0018] Figure 1 The utility model discloses a high resolution low stray low phase noise variable reference signal synthesizer for frequency synthesis.
[0019] In the drawing, 1, constant temperature crystal oscillator;2, power divider;3, operational amplifier;4, step tube frequency multiplier;5, first three-stage filter amplifier;6, phase-locked loop chip;7, low pass filter;8, frequency mixer;9, second three-stage filter amplifier. DETAILED DESCRIPTION
[0020] The embodiments of the utility model will be described below by specific specific examples, and those skilled in the art can easily understand other advantages and effects of the utility model from the content disclosed in the specification. Obviously, the described embodiment is a part of the embodiment of the utility model, not all. Based on the embodiment in the utility model, all other embodiments obtained by those skilled in the art without creating labor belong to the protection scope of the utility model.
[0021] Reference Figure 1 The utility model embodiment provides a kind of high resolution low stray low phase noise variable reference signal synthesizer for frequency synthesis, including constant temperature crystal oscillator 1, power divider 2, operational amplifier 3, step tube frequency multiplier 4, first three-stage filter amplifier 5, phase-locked loop chip 6, low pass filter 7, frequency mixer 8 and second three-stage filter amplifier 9;
[0022] The output end of the constant temperature crystal oscillator 1 is connected to the input end of the power divider 2, the first output end of the power divider 2 is electrically connected to the input end of the operational amplifier 3, and the second output end of the power divider 2 is electrically connected to the input pin of the phase-locked loop chip 6.
[0023] The output end of the operational amplifier 3 is electrically connected to the input end of the step-tube frequency multiplier 4, the output end of the step-tube frequency multiplier 4 is electrically connected to the input end of the first three-stage filter amplifier 5, and the output end of the first three-stage filter amplifier 5 is electrically connected to the local oscillator port of the mixer 8.
[0024] The output pin of the phase-locked loop chip 6 is electrically connected to the input end of the low-pass filter 7, the output end of the low-pass filter 7 is electrically connected to the intermediate frequency port of the local oscillator port of the mixer 8, and the radio frequency port of the mixer 8 is electrically connected to the input end of the second three-stage filter amplifier 9.
[0025] In the embodiment, the phase-locked loop chip 6 is LMX2572 of Ti company, the power consumption is 0.3 W, the constant temperature crystal oscillator 1 provides a 100 MHz fixed reference signal, the VCO (voltage controlled oscillator) of the phase-locked loop chip 6 outputs a decimal synthesis high-resolution basic signal, and then is divided by the internal frequency divider, so that the small number of frequency spurs is improved by 20lgN. The VCO frequency range is 3200 MHz-6400 MHz, 64 frequency output is 50 MHz-100 MHz, the resolution is <1 mHz, the spurs are -85 dBc- -95 dBc, and the output spur level is equivalent to that of the DDS, and the phase noise is better than most DDS chips. The output signal of the phase-locked loop chip 6 is mixed with the high-order frequency multiplication signal of the constant temperature crystal oscillator 1 to synthesize a variable reference signal.
[0026] In this embodiment, the constant temperature crystal oscillator 1 is used to provide a fixed reference signal; the power divider 2 is used to divide the fixed reference signal provided by the constant temperature crystal oscillator 1 into two paths. The operational amplifier 3 is used to amplify the signal allocated by the power divider 2, and the step-tube frequency multiplier 4 is used to process the signal amplified by the operational amplifier 3 into a comb spectrum signal containing high-order harmonics. The first three-stage filter amplifier 5 is used to amplify the high-order harmonic comb spectrum signal processed by the step-tube frequency multiplier 4 to select a fixed high-order harmonic signal as the local oscillator signal of the frequency mixer 8. The phase-locked loop chip 6 is used to frequency divide the signal allocated by the power divider 2 to obtain a 50MHz-100MHz high-resolution variable reference signal. The low-pass filter 7 is used to low-pass filter the 50MHz-100MHz high-resolution variable reference signal output by the phase-locked loop chip 6 to serve as the intermediate frequency input signal of the frequency mixer 8 for up-mixing. The second three-stage filter amplifier 9 is used to three-stage filter and amplify the up-mixing output signal of the frequency mixer 8 to select a variable reference signal.
[0027] Specifically, the constant temperature crystal oscillator 1 outputs a 100MHz signal, which is divided into two paths by the power divider 2. One path provides a high-order frequency multiplication excitation signal to the step-tube frequency multiplier 4, and the other path provides a fixed reference signal to the LMX2572 phase-locked loop chip 6. The step-tube frequency multiplier 4 first amplifies the 100MHz signal output by the power divider 2 to 20dBm, then drives the step-tube frequency multiplier 4 to generate a comb spectrum signal rich in high-order harmonics, and finally selects a fixed high-order harmonic signal as the local oscillator signal of the subsequent frequency mixer 8 through the first three-stage filter amplifier 5.
[0028] Among them, the VCO output of the phase-locked loop chip 6 is frequency divided by 64 to obtain a 50MHz-100MHz high-resolution variable reference signal. According to the specific frequency synthesis scheme planning, the required frequency range is selected, and the higher the output frequency, the lower the integer boundary spurious signal. The signal output by the phase-locked loop chip 6 is low-pass filtered by the low-pass filter 7 to serve as the intermediate frequency input signal of the subsequent frequency mixer 8 for up-mixing. According to the overall frequency planning scheme, the frequency range of the variable reference signal and the spurious requirement of the variable reference signal are determined. The up-mixing output signal of the frequency mixer 8 is selected by the second three-stage filter amplifier to obtain a variable high-resolution low-spurious low-phase-noise variable reference signal. The output variable reference signal is 1600MHz (100MHz intermediate frequency output minus 1700MHz local oscillator).
[0029] The utility model discloses a constant temperature crystal oscillator 1, power divider 2, operational amplifier 3, step tube frequency multiplier 4, first tertiary filter amplifier 5, phase-locked loop chip 6, low pass filter 7, frequency mixer 8 and second tertiary filter amplifier 9, the output of constant temperature crystal oscillator 1 is connected power divider 2's input, power divider 2's first output and operational amplifier 3's input are connected, and power divider 2's second output and phase-locked loop chip 6's input pin are connected, operational amplifier 3's output and step tube frequency multiplier 4's input are connected, and step tube frequency multiplier 4's output and first tertiary filter amplifier 5's input are connected, and first tertiary filter amplifier 5's output and frequency mixer 8's local oscillator port are connected, phase-locked loop chip 6's output pin and low pass filter 7's input are connected, and low pass filter 7's output and frequency mixer 8's local oscillator port are connected, and frequency mixer 8's radio frequency port and second tertiary filter amplifier 9's input are connected, the utility model discloses through phase-locked loop chip 6 replaces DDS and realizes the synthesis of variable reference signal, and area, cost and power consumption are all obviously lower than DDS, although frequency resolution index is lower than DDS, but the vast majority of application demand can satisfy, under the condition that frequency resolution meets the requirement, can utilize lower cost, and simple circuit design realizes wide frequency range, high resolution, low spurious and low phase noise variable reference signal, lower power consumption and volume provide strong support for the miniaturization design of frequency source, can simplify the complexity of frequency source synthesis, improve the reliability of product, effectively reduce the technical risk of project, shorten the development cycle of project, reduce the technical requirement of control circuit simultaneously, simplify the complexity of microwave division system, thereby reduce the cost of overall system.
[0030] Although the utility model has been described in detail above with general description and specific embodiment, but on the basis of the utility model, can make some modifications or improvement to it, which is obvious to the person skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the utility model, all belong to the range of the utility model claimed.
Claims
1. A high resolution low spurious low phase noise variable reference signal synthesizer for frequency synthesis, characterized by, The constant temperature crystal oscillator (1), the power divider (2), the operational amplifier (3), the step tube frequency multiplier (4), the first three-stage filter amplifier (5), the phase-locked loop chip (6), the low-pass filter (7), the frequency mixer (8) and the second three-stage filter amplifier (9) are included. The output end of the constant temperature crystal oscillator (1) is connected with the input end of the power divider (2), the first output end of the power divider (2) is electrically connected with the input end of the operational amplifier (3), and the second output end of the power divider (2) is electrically connected with the input pin of the phase-locked loop chip (6). The output end of the operational amplifier (3) is electrically connected with the input end of the step tube frequency multiplier (4), the output end of the step tube frequency multiplier (4) is electrically connected with the input end of the first three-stage filter amplifier (5), and the output end of the first three-stage filter amplifier (5) is electrically connected with the local oscillator port of the frequency mixer (8). The output pin of the phase-locked loop chip (6) is electrically connected with the input end of the low-pass filter (7), the output end of the low-pass filter (7) is electrically connected with the local oscillator port of the frequency mixer (8), and the intermediate frequency port of the frequency mixer (8) is electrically connected with the radio frequency port of the second three-stage filter amplifier (9).
2. The high resolution low spurious low phase noise variable reference signal synthesizer for frequency synthesis as claimed in claim 1, wherein, The constant temperature crystal oscillator (1) is used for providing a fixed reference signal. The power divider (2) is used for dividing the fixed reference signal provided by the constant temperature crystal oscillator (1) into two paths.
3. The high resolution low spurious low phase noise variable reference signal synthesizer for frequency synthesis as claimed in claim 2, wherein, The operational amplifier (3) is used for amplifying the signal distributed by the power divider (2), and the step tube frequency multiplier (4) is used for processing the signal amplified by the operational amplifier (3) into a comb spectrum signal containing high-order harmonics.
4. The high resolution low spurious low phase noise variable reference signal synthesizer for frequency synthesis as claimed in claim 3, wherein, The first three-stage filter amplifier (5) is used for amplifying the comb spectrum signal containing high-order harmonics processed by the step tube frequency multiplier (4) to select a fixed high-order harmonic signal as the local oscillator signal of the frequency mixer (8).
5. The high resolution low spurious low phase noise variable reference signal synthesizer for frequency synthesis as claimed in claim 3, wherein, The phase-locked loop chip (6) is used for frequency dividing the signal distributed by the power divider (2) to obtain a 50MHz-100MHz high-resolution variable reference signal.
6. The high resolution low spurious low phase noise variable reference signal synthesizer for frequency synthesis as claimed in claim 5, wherein, The low-pass filter (7) is used for low-pass filtering the 50MHz-100MHz high-resolution variable reference signal output by the phase-locked loop chip (6) to serve as the intermediate frequency input signal of the frequency mixer (8) for up-mixing.
7. The high resolution low spurious low phase noise variable reference signal synthesizer for frequency synthesis as claimed in claim 6, wherein, The second three-stage filter amplifier (9) is used for three-stage filter amplification of the up-mixing output signal of the frequency mixer (8) to select a variable reference signal.