Low-cost broadband direct synthesis type frequency source

Abstract

The invention discloses a low-cost broadband direct synthesis type frequency source, belongs to the technical field of radar communication, and mainly solves the problem that a traditional direct synthesis type frequency source cannot simultaneously realize low phase noise, short frequency hopping time and low cost. The frequency source comprises a harmonic generation circuit, a power division circuit connected with the harmonic generation circuit, a switch matrix connected with the power division circuit, and a frequency mixing synthesis circuit connected with the switch matrix. Wherein the harmonic generation circuit is used for generating a harmonic signal, the power division circuit is used for dividing the harmonic signal into six paths, and the switch matrix is used for outputting two paths of 12-17GHz signals from the power-divided signals. Compared with the traditional direct synthesis type frequency source, the direct synthesis type frequency source disclosed by the invention has the advantages that one harmonic generator and one switch filter group are omitted, so that the direct synthesis type frequency source disclosed by the invention realizes a low-cost broadband direct synthesis type frequency source.

Description

Technical Field

[0001] The present invention relates to the field of radar communication technology, in particular to a low-cost broadband direct synthesis frequency source. Background Art

[0002] The frequency source is the basic signal source of the electronic system. In modern electronic technology, the frequency source has become the core component of the electronic system and is widely used in radar, communication, measurement and control, countermeasures and navigation. With the development of modern electronic technology, the performance of electronic equipment has been continuously improved, and the functions have been continuously increased. At the same time, higher requirements have been put forward for the performance of frequency sources in all aspects. The indicators of frequency sources mainly include: miniaturization, small steps, high stability, ultra-wideband, low phase noise, low spurious, low power consumption, agile frequency change, fast start-up, etc. It is difficult to take all aspects into consideration. At the same time, the emphasis on the requirements of various indicators of frequency sources in different application fields is also different. Therefore, when designing frequency sources, it is often necessary to combine the actual application scenarios and make trade-offs and compromises on various indicators.

[0003] Directly synthesized frequency sources are an important part of modern electronic systems. With the rapid development of technologies such as radar, navigation, communication, and space electronic equipment, the system's requirements for directly synthesized frequency sources are becoming increasingly higher. Directly synthesized frequency sources have fast frequency hopping time and low output phase noise, but they are expensive. Therefore, how to reduce the cost of directly synthesized frequency sources will attract more and more attention.

[0004] like Figure 1 As shown, the traditional direct synthesis frequency source needs to use two harmonic generators, which is expensive. The 2.4GHz~3.4GHz signal is generated by a harmonic generator, which needs to suppress the main signal ±100MHz, has a high rectangular coefficient requirement, and has a low frequency. A dielectric filter is required, which is expensive and large in size, and is not easy to miniaturize. Summary of the invention

[0005] The purpose of the present invention is to provide a low-cost broadband direct synthesis frequency source, mainly to solve the problem that the traditional direct synthesis frequency source cannot achieve low phase noise, fast frequency hopping time and low cost at the same time.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A low-cost broadband direct synthesis frequency source comprises a harmonic generating circuit, a power dividing circuit connected to the harmonic generating circuit, a switch matrix connected to the power dividing circuit, and a frequency mixing synthesis circuit connected to the switch matrix; wherein the harmonic generating circuit is used to generate harmonic signals, the power dividing circuit is used to power divide the harmonic signals into 6 paths, and the switch matrix is ​​used to output the power divided signals into 2 paths of 12-17 GHz signals; wherein one path of 12-17 GHz signals is used as a local oscillator signal of the frequency mixing synthesis circuit; and the other path of 12-17 GHz signals is used as an intermediate frequency signal of the frequency mixing synthesis circuit after being processed.

[0007] Furthermore, in the present invention, the harmonic generating circuit includes a first frequency multiplier, a first bandpass filter, a second frequency multiplier, a second bandpass filter and a harmonic generator connected in sequence; wherein the reference clock signal is input to the first frequency multiplier, and after frequency multiplication and filtering, the signal is passed through the harmonic generator to generate a harmonic signal.

[0008] Furthermore, in the present invention, the power division circuit is composed of a one-to-two power divider and two one-to-three power dividers; wherein the input end of the one-to-two power divider is connected to the output end of the harmonic generator, and the two output ends of the one-to-two power divider are respectively connected to the input ends of the two one-to-three power dividers; and the output ends of the two one-to-three power dividers are both connected to the switch matrix.

[0009] Furthermore, in the present invention, the switch matrix is ​​composed of 6 bandpass filters, 6 one-to-two power dividers and two SP6T switches; wherein the input ends of the 6 bandpass filters are respectively connected to the 6 output ends formed by the two one-to-three power dividers; the output ends of the 6 bandpass filters are respectively connected to the input ends of the 6 one-to-two power dividers, and the two output ends of each one-to-two power divider are respectively connected to the input ends of the two SP6T switches; and the 12 output ends formed by the two SP6T switches are connected to the mixing synthesis circuit.

[0010] Furthermore, in the present invention, the mixing synthesis circuit is composed of a mixer, a frequency divider, a low-pass filter and a switch filter group; wherein the local oscillator input end of the mixer is connected to the six output ends of an SP6T switch, the input end of the frequency divider is connected to the six output ends of another SP6T switch, the output end of the frequency divider is connected to the intermediate frequency input end of the mixer after passing through a low-pass filter, the RF output end of the mixer is connected to the input end of the switch filter group, and the output end of the switch filter group outputs the synthesized frequency source.

[0011] Further, in the present invention, the first frequency multiplier is a ×2 frequency multiplier, and the second frequency multiplier is a ×5 frequency multiplier.

[0012] Furthermore, in the present invention, the frequency divider is a ÷5 frequency divider.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses a harmonic generator to generate a 12-17 GHz signal, then outputs a 12-17 GHz signal as a mixed local oscillator signal through a switch matrix, outputs a 12-17 GHz signal to generate a 2.4-3.4 GHz signal through a ÷5 frequency divider, and the 2.4-3.4 GHz signal is filtered by a low-pass filter to be used as a mixed intermediate frequency signal, which is mixed with the 12-17 GHz signal to generate a 10-20 GHz broadband direct synthesis frequency source. Compared with a traditional direct synthesis frequency source, one harmonic generator and one switch filter group are used less, so the direct synthesis frequency source in the present invention realizes a low-cost broadband direct synthesis frequency source. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the circuit structure diagram of the traditional direct synthesis frequency source.

[0015] Figure 2 It is a circuit structure diagram of the direct synthesis frequency source in the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The embodiments of the present invention include but are not limited to the following embodiments.

[0017] like Figure 2 As shown, the present invention discloses a low-cost broadband direct synthesis frequency source, including a harmonic generating circuit, a power dividing circuit connected to the harmonic generating circuit, a switch matrix connected to the power dividing circuit, and a mixing synthesis circuit connected to the switch matrix; wherein the harmonic generating circuit is used to generate a harmonic signal, the power dividing circuit is used to power divide the harmonic signal into 6 paths, and the switch matrix is ​​used to output the power-divided signal into 2 paths of 12-17 GHz signals; wherein one path of 12-17 GHz signal is used as a local oscillator signal of the mixing synthesis circuit; and the other path of 12-17 GHz signal is used as an intermediate frequency signal of the mixing synthesis circuit after being processed.

[0018] In this embodiment, the harmonic generation circuit includes a first frequency multiplier, a first bandpass filter, a second frequency multiplier, a second bandpass filter and a harmonic generator connected in sequence; wherein, the reference clock signal is input to the first frequency multiplier, and the signal after frequency multiplication and filtering is passed through the harmonic generator to generate a harmonic signal. The first frequency multiplier is a ×2 frequency multiplier, and the second frequency multiplier is a ×5 frequency multiplier. The reference clock uses a 100MHz signal, which is multiplied to a 200MHz signal by a ×2 frequency multiplier, and then filtered out by the first bandpass filter, and then the 200MHz signal is passed through a ×5 frequency multiplier to generate a 1000MHz signal, and then filtered out by the second bandpass filter, and the 1000MHz signal is passed through the harmonic generator to generate a harmonic signal.

[0019] In this embodiment, the power division circuit is composed of a one-to-two power divider ( Figure 2 The power divider 1) and two one-to-three power dividers ( Figure 2 The power divider 2 and power divider 3 in the figure are used as the power divider; the input end of the one-to-two power divider is connected to the output end of the harmonic generator, and the two output ends of the one-to-two power divider are respectively connected to the input ends of the two one-to-three power dividers; the output ends of the two one-to-three power dividers are connected to the switch matrix. The harmonic signal is divided into two paths by the one-to-two power divider, and then divided by two one-to-three power dividers, and finally 6 paths of power division are realized.

[0020] In this embodiment, the switch matrix consists of 6 bandpass filters, 6 one-to-two power dividers ( Figure 2 The power divider 4-9) and two SP6T switches ( Figure 2 The 12-way power synthesizer circuit is composed of 6 bandpass filters (SP6T1 and SP6T2); the input ends of the 6 bandpass filters are respectively connected to the 6 output ends formed by the two 1-to-3 power dividers; the output ends of the 6 bandpass filters are respectively connected to the input ends of the 6 1-to-2 power dividers, and the two output ends of each 1-to-2 power divider are respectively connected to the input ends of the two SP6T switches; the 12 output ends formed by the two SP6T switches are connected to the mixing synthesis circuit. In the switch matrix, the 6-way power-divided harmonic signal is respectively selected by 6 bandpass filters to obtain 12GHz signal, 13GHz signal, 14GHz signal, 15GHz signal, 16GHz signal and 17GHz signal; each selected signal is then divided into two ways by the 1-to-2 power divider connected to each of them; after the two-way signal enters the two SP6T switches respectively, the output of one SP6T switch is directly used as the local oscillator input of the mixing synthesis circuit, and the output of the other SP6T switch is used as the intermediate frequency input of the mixing synthesis circuit after frequency division processing.

[0021] In this embodiment, the mixing synthesis circuit is composed of a mixer, a frequency divider, a low-pass filter and a switch filter group; wherein the local oscillator input terminal ( Figure 2 The LO terminal in the intermediate frequency mixer is connected to the 6 output terminals of a SP6T switch, the input terminal of the frequency divider is connected to the 6 output terminals of another SP6T switch, and the output terminal of the frequency divider is connected to the intermediate frequency input terminal ( Figure 2 The IF terminal of the mixer is connected to the RF output terminal of the mixer ( Figure 2The RF end in the intermediate mixer is connected to the input end of the switch filter group, and the output end of the switch filter group outputs the synthesized frequency source. Among them, the frequency divider is a ÷5 frequency divider. In the switch matrix, the 12GHz signal, 13GHz signal, 14GHz signal, 15GHz signal, 16GHz signal and 17GHz signal output by one SP6T switch are directly used as the local oscillator input of the mixer, and the 12GHz signal, 13GHz signal, 14GHz signal, 15GHz signal, 16GHz signal and 17GHz signal output by another SP6T switch are generated after the ÷5 frequency divider to generate 2.4GHz signal, 2.6GHz signal, 2.8GHz signal, 3.0GHz signal, 3.2GHz signal and 3.4GHz signal. The above 6 signals are filtered by a low-pass filter as the intermediate frequency input of the mixer; among them, 2.4~3.0GHz and 13GHz are mixed to generate 10~10.6GHz, and 2.4~3.4GHz and 14GHz are mixed to generate 10.6~11.6GHz. Mixing 2.4-3.0 GHz with 15 GHz generates 11.6-12.6 GHz, mixing 2.4-3.0 GHz with 16 GHz generates 12.6-13.6 GHz, mixing 2.4-3.0 GHz with 17 GHz generates 13.6-14.6 GHz, mixing 2.6-3.4 GHz with 12 GHz generates 14.6-15.4 GHz, mixing 2.4-3.4 GHz with 13 GHz generates 15.4-16.4 GHz, mixing 2.4-3.0 GHz with 14 GHz generates 16.4-17.4 GHz, mixing 2.4-3.0 GHz with 15 GHz generates 17.4-18.4 GHz, mixing 2.4-3.0 GHz with 16 GHz generates 18.4-19.4 GHz, and mixing 2.4-3.0 GHz with 17 GHz generates 19.4-20 GHz. The 10-20 GHz generated by the mixing is filtered out by the switching filter group to remove the mixing intermodulation spurious and then output a 10-20 GHz broadband signal.

[0022] Through the above design, the direct synthesis frequency source in the present invention uses a harmonic generator to generate a 12-17GHz signal, and then outputs a 12-17GHz signal as a mixed local oscillator signal through a switch matrix, outputs a 12-17GHz signal and generates a 2.4-3.4GHz signal through a ÷5 divider, and the 2.4-3.4GHz signal is filtered by a low-pass filter and then used as a mixed intermediate frequency signal and mixed with the 12-17GHz signal to generate a 10-20GHz broadband direct synthesis frequency source. Compared with the traditional direct synthesis frequency source, one harmonic generator and one switch filter group are used less, so the direct synthesis frequency source in the present invention realizes a low-cost broadband direct synthesis frequency source.

[0023] The above embodiment is only one of the preferred implementation modes of the present invention and should not be used to limit the protection scope of the present invention. Any changes or modifications that are made to the main design concept and spirit of the present invention and have no substantive significance, and the technical problems they solve are still consistent with the present invention, should be included in the protection scope of the present invention.

Claims

1. A low-cost broadband direct synthesis frequency source, characterized in that: It includes a harmonic generating circuit, a power dividing circuit connected to the harmonic generating circuit, a switch matrix connected to the power dividing circuit, and a frequency mixing synthesis circuit connected to the switch matrix; wherein the harmonic generating circuit is used to generate harmonic signals, the power dividing circuit is used to power divide the harmonic signals into 6 paths, and the switch matrix is ​​used to output the power divided signals into 2 paths of 12-17 GHz signals; wherein one path of 12-17 GHz signal is used as the local oscillator signal of the frequency mixing synthesis circuit; and the other path of 12-17 GHz signal is used as the intermediate frequency signal of the frequency mixing synthesis circuit after being processed.

2. A low-cost broadband direct synthesis frequency source according to claim 1, characterized in that: The harmonic generating circuit includes a first frequency multiplier, a first bandpass filter, a second frequency multiplier, a second bandpass filter and a harmonic generator which are connected in sequence; wherein the reference clock signal is input to the first frequency multiplier, and after frequency multiplication and filtering, the signal is passed through the harmonic generator to generate a harmonic signal.

3. A low-cost broadband direct synthesis frequency source according to claim 2, characterized in that: The power division circuit is composed of a one-to-two power divider and two one-to-three power dividers; wherein the input end of the one-to-two power divider is connected to the output end of the harmonic generator, and the two output ends of the one-to-two power divider are respectively connected to the input ends of the two one-to-three power dividers; and the output ends of the two one-to-three power dividers are both connected to the switch matrix.

4. A low-cost broadband direct synthesis frequency source according to claim 3, characterized in that: The switch matrix is ​​composed of 6 bandpass filters, 6 one-to-two power dividers and two SP6T switches; wherein the input ends of the 6 bandpass filters are respectively connected to the 6 output ends formed by the two one-to-three power dividers; the output ends of the 6 bandpass filters are respectively connected to the input ends of the 6 one-to-two power dividers, and the two output ends of each one-to-two power divider are respectively connected to the input ends of the two SP6T switches; and the 12 output ends formed by the two SP6T switches are connected to the mixing synthesis circuit.

5. A low-cost broadband direct synthesis frequency source according to claim 4, characterized in that: The mixing synthesis circuit is composed of a mixer, a frequency divider, a low-pass filter and a switch filter group; wherein the local oscillator input end of the mixer is connected to the six output ends of an SP6T switch, the input end of the frequency divider is connected to the six output ends of another SP6T switch, the output end of the frequency divider is connected to the intermediate frequency input end of the mixer after passing through a low-pass filter, the radio frequency output end of the mixer is connected to the input end of the switch filter group, and the output end of the switch filter group outputs the synthesized frequency source.

6. A low-cost broadband direct synthesis frequency source according to claim 5, characterized in that: The first frequency multiplier is a ×2 frequency multiplier, and the second frequency multiplier is a ×5 frequency multiplier.

7. A low-cost broadband direct synthesis frequency source according to claim 6, characterized in that: The frequency divider is a ÷5 frequency divider.

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