A broadband low-spurious millimeter-wave direct synthesis source circuit

Abstract

The present invention relates to a broadband low-stray millimeter wave direct synthesis source circuit, comprising a 100MHz crystal oscillator, a power divider 1, a harmonic generator, a power divider 2, a switch filter 1, an amplifier 1, a mixer 1, a filter amplifier, a direct digital synthesizer, a filter 1, a switch filter 2, an amplifier 2, a frequency divider, a mixer 2, a filter 2, an amplifier 3 and a sampling phase-locked medium oscillator. The power divider 1 and the power divider 2 both use two power dividers. The switch filter 1 and the switch filter 2 both use a three-choice switch filter. The frequency divider uses a binary frequency divider. It can be seen from the above technical solutions that the present invention can solve the deficiencies in the prior art, and while improving the frequency hopping time of the millimeter wave frequency source, it can also improve the stray index of the millimeter wave frequency source, and increase the imaging resolution and anti-interference ability of the millimeter wave radar.

Description

Technical Field

[0001] The present invention relates to the technical field of radar system integration, and in particular to a broadband low-stray millimeter-wave direct synthesis source circuit. Background Art

[0002] At present, in radar systems, millimeter wave direct synthesis source is a frequently used frequency source. In recent years, with the development of radar systems, millimeter wave radars are increasingly used in helicopter airborne systems. They have small antenna apertures and narrow beams, are easy to track at low elevation angles, resist interference from ground multipath and clutter, have high resolution for monitoring near-air targets, and are easy to detect small targets including power lines or poles. This has brought about the demand for millimeter wave direct synthesis sources. At present, most millimeter wave frequency sources are phase-locked loops that generate intermediate frequency signals and then up-convert them with frequency standard signals to generate local oscillator signals. The local oscillator signals are then up-converted with digital intermediate frequency signals to generate transmission signals. The frequency hopping time of the local oscillator signal is as long as tens of microseconds, and the spurious signals are large and cannot be avoided. Summary of the invention

[0003] The purpose of the present invention is to provide a broadband low-spurious millimeter-wave direct synthesis source circuit, which can solve the deficiencies in the prior art, improve the spurious index of the millimeter-wave frequency source while improving the frequency hopping time of the millimeter-wave frequency source, and increase the imaging resolution and anti-interference ability of the millimeter-wave radar.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A broadband low-spurious millimeter-wave direct synthesis source circuit comprises a crystal oscillator, a power divider 1, a harmonic generator, a power divider 2, a switch filter 1, an amplifier 1, a mixer 1, a filter amplifier, a direct digital synthesizer, a filter 1, a switch filter 2, an amplifier 2, a frequency divider, a mixer 2, a filter 2, an amplifier 3 and a sampling phase-locked dielectric oscillator; the output end of the crystal oscillator is connected to the input end of the power divider 1, the output end of the power divider 1 is respectively connected to the input end of the harmonic generator and the sampling phase-locked dielectric oscillator, the output end of the harmonic generator is connected to the input end of the power divider 2, the output end of the power divider 2 is respectively connected to the input end of the switch filter 1 and the filter amplifier, and the output end of the switch filter 1 is connected to the input end of the filter amplifier. The output terminal is connected to the input terminal of amplifier one, the output terminal of amplifier one is connected to the input terminal of mixer one, the output terminal of mixer one is connected to the input terminal of switch filter two, the output terminal of switch filter two is connected to the input terminal of amplifier two, the output terminal of amplifier two is connected to the input terminal of frequency divider, the output terminal of frequency divider is connected to the input terminal of mixer two, the input terminal of mixer two is also connected to the output terminal of sampling phase-locked medium oscillator, the output terminal of mixer two is connected to the input terminal of filter two, the output terminal of filter two is connected to the input terminal of amplifier three, the output terminal of filter amplifier is connected to the input terminal of direct digital synthesizer, the output terminal of direct digital synthesizer is connected to the input terminal of filter one, and the output terminal of filter one is connected to the input terminal of mixer one.

[0006] Furthermore, the crystal oscillator adopts a 100 MHz crystal oscillator.

[0007] Furthermore, the power divider 1 and the power divider 2 both adopt two power dividers.

[0008] Furthermore, the switch filter 1 and the switch filter 2 both adopt a three-select-one switch filter.

[0009] Furthermore, the frequency divider is a binary frequency divider.

[0010] It can be seen from the above technical solutions that the present invention can solve the deficiencies in the prior art, and while improving the frequency hopping time of the millimeter wave frequency source, it can also improve the spurious index of the millimeter wave frequency source, and increase the imaging resolution and anti-interference ability of the millimeter wave radar. The present invention has the characteristics of integration, small size, good reliability, simple design, low cost, etc., and is suitable for a variety of millimeter wave radar systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a circuit schematic diagram of the present invention.

[0012] in:

[0013] 1. Crystal oscillator, 2. Power divider 1, 3. Harmonic generator, 4. Power divider 2, 5. Switch filter 1, 6. Amplifier 1, 7. Mixer 1, 8. Filter amplifier, 9. Direct digital synthesizer, 10. Filter 1, 11. Switch filter 2, 12. Amplifier 2, 13. Divider, 14. Mixer 2, 15. Filter 2, 16. Amplifier 3, 17. Sampling phase-locked dielectric oscillator. DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with the accompanying drawings:

[0015] like Figure 1 A broadband low-spurious millimeter-wave direct synthesis source circuit is shown, comprising a crystal oscillator 1, a power divider 2, a harmonic generator 3, a power divider 2 4, a switch filter 1 5, an amplifier 1 6, a mixer 1 7, a filter amplifier 8, a direct digital synthesizer 9, a filter 1 10, a switch filter 2 11, an amplifier 2 12, a frequency divider 13, a mixer 2 14, a filter 2 15, an amplifier 3 16 and a sampling phase-locked dielectric oscillator 17.

[0016] The functions of each component are as follows:

[0017] The crystal oscillator 1 is a 100MHz crystal oscillator 1, which is used to generate a 100MHz reference signal. The power divider 12 is used to divide the 100MHz reference signal into two paths, one path entering the harmonic generator 3 and the other path entering the sampling phase-locked medium oscillator 17. The harmonic generator 3 is used to generate a rich 100MHz harmonic signal. The power divider 24 is used to divide the 100MHz harmonic signal generated by the harmonic generator 3 into two paths. The switch filter 15 is used to filter the 100MHz harmonic signal generated by the harmonic generator 3 and select three frequency standard signals in time sharing. The amplifier 16 is used to amplify the three frequency standard signals selected by the switch filter 15. The filter amplifier 8 is used to filter and amplify the 100MHz harmonic signal generated by the harmonic generator 3 as a reference clock for the direct digital synthesizer 9. The direct digital synthesizer 9 is used to generate a fast frequency hopping signal of 500MHz to 900MHz. The filter 10 is used to filter the fast frequency hopping signal generated by the direct digital synthesizer 9. The mixer 1 7 is used to mix the frequency standard signal with the fast frequency hopping signal generated by the direct digital synthesizer 9 to generate an intermediate frequency signal with a fast hopping frequency. The switch filter 2 11 is a three-select-one switch filter, which is used to filter the generated fast frequency hopping intermediate frequency signal. The amplifier 2 12 is used to amplify the generated fast frequency hopping intermediate frequency signal after filtering. The divider 13 is used to divide the generated fast frequency hopping intermediate frequency signal into two after filtering and amplification, which can improve the spurious index by 6dB. The sampling phase-locked dielectric oscillator 17 is used to generate a 32GHz signal and perform up-conversion mixing with the fast hopping intermediate frequency signal after the two-division. The mixer 2 14 is used to perform up-conversion mixing with the intermediate frequency signal after the two-division and the signal generated by the sampling phase-locked dielectric oscillator 17 to generate a millimeter wave signal. The filter 2 15 is used to filter the generated millimeter wave signal. The amplifier 3 16 is used to amplify the generated millimeter wave signal.

[0018] The output end of the crystal oscillator 1 is connected to the input end of the power divider 2, the output end of the power divider 2 is respectively connected to the input end of the harmonic generator 3 and the sampling phase-locked medium oscillator 17, the output end of the harmonic generator 3 is connected to the input end of the power divider 4, the output end of the power divider 4 is respectively connected to the input end of the switch filter 5 and the filter amplifier 8, the output end of the switch filter 5 is connected to the input end of the amplifier 6, the output end of the amplifier 6 is connected to the input end of the mixer 7, the output end of the mixer 7 is connected to the input end of the switch filter 11, and the output end of the switch filter 11 is connected to the input end of the amplifier 8. The input end of the amplifier 12 is connected to the input end of the frequency divider 13, the output end of the frequency divider 13 is connected to the input end of the mixer 2 14, the input end of the mixer 2 14 is also connected to the output end of the sampling phase-locked medium oscillator 17, the output end of the mixer 2 14 is connected to the input end of the filter 2 15, the output end of the filter 2 15 is connected to the input end of the amplifier 3 16, the output end of the filter amplifier 8 is connected to the input end of the direct digital synthesizer 9, the output end of the direct digital synthesizer 9 is connected to the input end of the filter 10, and the output end of the filter 10 is connected to the input end of the mixer 1 7. The power divider 1 2 and the power divider 2 4 both use two power dividers. The switch filter 1 5 and the switch filter 2 11 both use three-to-one switch filters. The frequency divider 13 uses a two-way frequency divider.

[0019] The working principle of the present invention is:

[0020] In the synthesis source circuit described in the present invention, the crystal oscillator 1 is used as a reference signal and is input into the harmonic generator 3 and the sampling phase-locked medium oscillator 17 respectively through the power divider 2. The harmonic generator 3 generates a rich 100MHz harmonic signal, which passes through the power divider 4, and the power output is selected by the filter amplifier 8 and given to the direct digital synthesizer 9 as a reference clock signal. The direct digital synthesizer 9 will output a fast frequency hopping signal of 500MHz to 900MHz, with a spurious suppression index of 70dBc and a frequency hopping time of 150ns. The other path is selected by the three-to-one switching filter 5 as three frequency standard signals with frequencies of 2000MHz, 2400MHz, and 2800MHz. The frequency standard signal and the fast frequency hopping signal of 500MHz to 900MHz are up-converted to generate an intermediate frequency signal with a fast hopping frequency of 2500MHz to 3700MHz. After the intermediate frequency signal passes through the binary divider 13, its spurious signal is optimized by 6dBc, which is also the innovation point of the present invention. The intermediate frequency signal becomes 1250MHz~1850MHz, and the spurious signal index is optimized to 76dBc. The intermediate frequency signal and the 32GHz signal output by the sampling phase-locked dielectric oscillator 17 are up-converted to generate a millimeter wave signal of 33.25GHz~33.85GHz, and its spurious suppression index is 76dBc, and the frequency hopping time is 150ns.

[0021] The embodiments described above are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A broadband low-spurious millimeter-wave direct synthesis source circuit, characterized in that: The invention comprises a crystal oscillator, a power divider 1, a harmonic generator, a power divider 2, a switch filter 1, an amplifier 1, a mixer 1, a filter amplifier, a direct digital synthesizer, a filter 1, a switch filter 2, an amplifier 2, a frequency divider, a mixer 2, a filter 2, an amplifier 3 and a sampling phase-locked dielectric oscillator; the output end of the crystal oscillator is connected to the input end of the power divider 1, the output end of the power divider 1 is respectively connected to the input ends of the harmonic generator and the sampling phase-locked dielectric oscillator, the output end of the harmonic generator is connected to the input end of the power divider 2, the output end of the power divider 2 is respectively connected to the input ends of the switch filter 1 and the filter amplifier, and the output end of the switch filter 1 is connected to the input end of the amplifier 1 The output of amplifier one is connected to the input of mixer one, the output of mixer one is connected to the input of switch filter two, the output of switch filter two is connected to the input of amplifier two, the output of amplifier two is connected to the input of binary divider, the output of binary divider is connected to the input of mixer two, the input of mixer two is also connected to the output of sampling phase-locked medium oscillator, the output of mixer two is connected to the input of filter two, the output of filter two is connected to the input of amplifier three, the output of filter amplifier is connected to the input of direct digital synthesizer, the output of direct digital synthesizer is connected to the input of filter one, and the output of filter one is connected to the input of mixer one.

2. A broadband low-spurious millimeter-wave direct synthesis source circuit according to claim 1, characterized in that: The crystal oscillator adopts a 100 MHz crystal oscillator.

3. A broadband low-spurious millimeter-wave direct synthesis source circuit according to claim 1, characterized in that: The power divider 1 and the power divider 2 both adopt two power dividers.

4. The broadband low-spurious millimeter-wave direct synthesis source circuit according to claim 1, characterized in that: The switch filter 1 and the switch filter 2 both adopt a three-select-one switch filter.

5. The broadband low-spurious millimeter-wave direct synthesis source circuit according to claim 1, characterized in that: The frequency divider is a binary frequency divider.

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