Broadband fine-stepping low-phase noise signal generation system

Abstract

The invention discloses a broadband fine-stepping low-phase noise signal generation system, relates to the field of broadband fine-stepping low-phase noise signal generation, and aims to solve the problem of ultra-low-phase noise broadband fine-stepping signal output. According to the system, intermediate-frequency signals in a multi-band frequency range are output in a segmented filtering mode and serve as intermediate-frequency input of a frequency mixer, dot-frequency local oscillation signals are input, frequency mixing is conducted through the frequency mixer, and frequency intervals of large-step local oscillation signals are filled with broadband small-step intermediate-frequency signals, so that the frequency range of the frequency mixer is widened. And through switch filtering, amplification, numerical control attenuation and coupling, a cross-octave small-step frequency reference signal is obtained, namely, a broadband fine-step signal with ultra-low phase noise is generated. According to the invention, a stepping signal with ultra-low phase noise and fine broadband is generated; intermediate-frequency signal input power is reasonably designed, a high-isolation switch is selected, and the harmonic suppression degree of intermediate-frequency signals is improved.

Description

Background Art

[0002] Phase noise is a random phase fluctuation that distorts the linear change trend of the signal generator phase. It is one of the important performance parameters in radar, radio communication, navigation and positioning applications. Phase noise is usually a limiting indicator of system performance. In order to meet the development needs of low-noise and low-spurious signal generators and improve the measurement capabilities of phase noise test systems, low phase noise signal generation technology has become an important research topic.

[0003] Therefore, it is necessary to provide a broadband fine-step low phase noise signal generation system. Summary of the invention

[0004] The present invention provides a broadband fine-step low phase noise signal generating system, which can generate broadband fine-step signals with ultra-low phase noise, and has a detection indication function of the output signal and a temperature monitoring function of temperature-sensitive parts, and can solve the problem of ultra-low phase noise broadband fine-step signal output.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] This specification provides a broadband fine-step low phase noise signal generation system, which includes an intermediate frequency filter selection module, a mixing filter selection module, and an amplification output module;

[0007] The intermediate frequency filter selection module is configured to receive a DDS reference signal and an external intermediate frequency input signal as input signals; input the input signal into the SPDT switch for selection, and input the selected signal into the first switch filter group for segmented filtering processing, and output signals within multiple frequency ranges;

[0008] The mixing filter selection module is configured to receive the point frequency local oscillator signal from the external input local oscillator generating unit and the signal within the multiple frequency ranges; respectively process the signal within the multiple frequency ranges and the point frequency local oscillator signal through an attenuator and a power amplifier, and then input them into the mixer for mixing; and output the mixed signal after switching filtering through a second switching filter group;

[0009] The amplification output module is configured to receive the signal output by the second switch filter group, and process it through a power amplifier, a digitally controlled attenuator, and a coupler in sequence to obtain a frequency reference signal with a small step across an octave.

[0010] In some preferred embodiments, the frequency range of the DDS reference signal is 500-1000 MHz; the frequency range of the external intermediate frequency input signal is 500-1000 MHz; the signal within the multi-segment frequency range is a signal within a 3-segment frequency range; the frequency range of the cross-octave small step frequency reference signal is 6.0 GHz-12.0 GHz.

[0011] In some preferred embodiments, the spot frequency local oscillator signal is within the range of 6.0 GHz to 12.0 GHz, and fills the signals within the multiple frequency ranges according to a set frequency step of 1 GHz.

[0012] In some preferred embodiments, the SPDT switch comprises a high isolation switch.

[0013] In some preferred embodiments, the first switching filter group includes three filters, respectively serving as a first filter, a second filter, and a third filter; the first filter is used to filter the input signal in a frequency band of 500 to 650 MHz; the second filter is used to filter the input signal in a frequency band of 550 to 800 MHz; the third filter is used to filter the input signal in a frequency band of 700 to 1000 MHz.

[0014] In some preferred embodiments, the amplifier, the attenuator and the digitally controlled attenuator all operate in a linear region.

[0015] In some preferred embodiments, the circuit structure of the system adopts a slotted structure; the circuit of the system adopts a cover plate for shielding.

[0016] In some preferred embodiments, the system further comprises an amplitude detection module and a temperature monitoring module;

[0017] The amplitude detection module is configured to perform amplitude detection on the cross-octave small-step frequency reference signal, and the signal after amplitude detection is fed back to the control unit;

[0018] The temperature monitoring module is configured to detect the temperature sensitive parts of the amplifier, and the signal after the temperature detection is fed back to the control unit.

[0019] In some preferred embodiments, the control unit controls the SPDT switch, the switch filter bank, and the digitally controlled attenuator.

[0020] In some preferred embodiments, the digitally controlled attenuator is a programmable attenuator for performing precise attenuation control on a signal.

[0021] At least one of the above technical solutions adopted in the embodiments of this specification can achieve the following beneficial effects:

[0022] (1) The present invention outputs a signal within a three-segment frequency range through segmented filtering of an intermediate frequency signal as an intermediate frequency input of a mixer, and inputs a point-frequency local oscillator signal with a frequency step of gigahertz. The mixer performs mixing to fill the broadband small-step intermediate frequency signal into the frequency interval of the large-step local oscillator signal, and then obtains a cross-octave small-step frequency reference signal through switch filtering, amplification, digitally controlled attenuation, and coupling, thereby generating a broadband fine-step signal with ultra-low phase noise;

[0023] (2) The present invention reasonably designs the input power of the intermediate frequency signal so that the noise of the mixer is well controlled; the switch of the intermediate frequency filter module uses a high isolation switch to improve the harmonic suppression of the intermediate frequency signal and ensure that the in-band noise after mixing can meet the noise suppression requirements of the overall circuit;

[0024] (3) The present invention can achieve spurious suppression better than 75dBc, and the phase noise at 10GHz is better than -82dBc / Hz@10Hz, -98dBc / Hz@100Hz, -121dBc / Hz@1kHz, -140dBc / Hz@10kHz, -150dBc / Hz@100kHz,

[0025] -154dBc / Hz@1MHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0027] Figure 1 A principle block diagram of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0028] Figure 2 This is a spurious suppression waveform diagram of a 6 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0029] Figure 3 This is a spurious suppression waveform diagram of a 7 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0030] Figure 4 This is a spurious suppression waveform diagram of an 8 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0031] Figure 5This is a spurious suppression waveform diagram of a 9 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0032] Figure 6 This is a spurious suppression waveform diagram of a 10 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0033] Figure 7 This is a spurious suppression waveform diagram of an 11 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0034] Figure 8 This is a spurious suppression waveform diagram of a 12 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0035] Fig. 9 This is a phase noise waveform diagram of a 6 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of the present specification.

[0036] Fig.10 This is a phase noise waveform diagram of a 7 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0037] Fig.11 This is a phase noise waveform diagram of an 8 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0038] Fig.12 This is a phase noise waveform diagram of a 9 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0039] Fig.13 This is a phase noise waveform diagram of a 10 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0040] Fig.14 This is a phase noise waveform diagram of an 11 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification.

[0041] Fig.15 This is a phase noise waveform diagram of a 12 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0043] The technical solutions provided by various embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0044] This manual outputs 3 signals of 500-650MHz, 550-800MHz, and 700-1000MHz through segmented filtering of the intermediate frequency signal, and the point-frequency local oscillator signal with a frequency step of 1GHz (respectively 6GHz, 7GHz, 8GHz, 9GHz, 10GHz, 11GHz, and 12GHz), which are respectively processed by the attenuator and power amplifier and input into the mixer for mixing, and the broadband small-step intermediate frequency signal is filled into the frequency interval of the large-step local oscillator signal, and then through switch filtering, amplification, digital control attenuation, and coupling, a 6G-12G cross-octave small-step frequency reference signal is obtained, that is, a broadband fine-step signal with ultra-low phase noise is generated. The details are as follows:

[0045] The first embodiment of this specification provides a broadband fine-step low phase noise signal generation system, such as Figure 1 As shown, it includes an intermediate frequency filter selection module, a mixing filter selection module, and an amplification output module. The intermediate frequency filter selection module is configured to receive a 500-1000MHz DDS reference signal and a 500-1000MHz external intermediate frequency signal as an input signal, enter the SPDT switch for selection, and is controlled by a control unit. The SPDT switch includes a high isolation switch, and a switch chip with high harmonic suppression can also be selected to select between the DDS reference signal and the external intermediate frequency signal, thereby improving the harmonic suppression of the intermediate frequency signal and ensuring that the in-band spurious after mixing can meet the spurious suppression requirements of the overall circuit. The selected input signal is input to the first switch filter group, and the first switch The switch filter group is controlled by the control unit to perform segmented filtering and output signals within multiple frequency ranges. The present application preferably includes three filters in the first switch filter group, which are respectively used as the first filter, the second filter, and the third filter; the first filter is used to filter the input signal in the frequency range of 500 to 650 MHz; the second filter is used to filter the input signal in the frequency range of 550 to 800 MHz; the third filter is used to filter the input signal in the frequency range of 700 to 1000 MHz, and output signals within the three frequency ranges of 500 to 650 MHz, 550 to 800 MHz, and 700 to 1000 MHz;

[0046] The mixing filter selection module is configured to receive a point frequency local oscillator signal from an externally input local oscillator generating unit and a signal within the multiple frequency ranges. The present application preferably sets the set GHz to 1 GHz, that is, the point frequency local oscillator signal steps in frequency by 1 GHz each time within the range of 6 GHz to 12 GHz (6 GHz, 7 GHz, 8 GHz, 9 GHz, 10 GHz, 11 GHz, 12 GHz), and fills in the signals within the multiple frequency ranges (preferably signals within 3 frequency ranges); the signals within the multiple frequency ranges and the point frequency local oscillator signal are processed by an attenuator and a power amplifier respectively and then input into a mixer for mixing; the mixed signal is output after switching filtering by a second switching filter group. Since the point frequency local oscillator signal of the present application steps in frequency by 1 GHz each time within the range of 6 GHz to 12 GHz (6 GHz, 7 GHz, 8 GHz, 9 GHz, 10 GHz, 11 GHz, 12 GHz), the second switching filter preferably includes 12 filters, and the first filter is for 500-650 MHz, 550-650 MHz, and 550-650 MHz. The first filter filters the signals from 500-650MHz, 550-800MHz, 700-1000MHz to 6GHz to 6.5GHz. The second filter filters the signals from 500-650MHz, 550-800MHz, 700-1000MHz to 6.5GHz to 7GHz. The third filter filters the signals from 500-650MHz, 550-800MHz, 700-1000MHz to 7GHz to 7.5GHz. The fourth filter filters the signals from 500-650MHz, 550-800MHz, 700-1000MHz to 50~800MHz, 700~1000MHz fill in 7.5GHz to 8GHz signal filtering; in this way, the same logic continues until the 11th filter fills in 500~650MHz, 550~800MHz, 700~1000MHz fill in 11GHz to 11.5GHz signal filtering, the 12th filter fills in 500~650MHz, 550~800MHz, 700~1000MHz fill in 11.5GHz to 12GHz signal filtering;

[0047] The amplification output module is configured to receive the signal output by the second switch filter group, and process it in sequence through a power amplifier, a digitally controlled attenuator, and a coupler. The digitally controlled attenuator is controlled by a control unit to obtain a cross-octave small-step frequency reference signal. The frequency range of the cross-octave small-step frequency reference signal is 6.0 GHz to 12.0 GHz. Figures 2 to 8 , the present invention can achieve a spurious suppression better than 75dBc, Figure 2 A spurious suppression waveform diagram of a 6GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Figure 3A spurious suppression waveform diagram of a 7GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Figure 4 This is a spurious suppression waveform of an 8GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Figure 5 A spurious suppression waveform diagram of a 9GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Figure 6 A spurious suppression waveform diagram of a 10 GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Figure 7 This is a spurious suppression waveform of an 11 GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Figure 8 A spurious suppression waveform diagram of a 12 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification;

[0048] See also Figures 9 to 15 The present invention can achieve a 10GHz phase noise better than -82dBc / Hz@10Hz, -98dBc / Hz@100Hz, -121dBc / Hz@1kHz, -140dBc / Hz@10kHz, -150dBc / Hz@100kHz, -154dBc / Hz@1MHz, Fig. 9 A phase noise waveform diagram of a 6 GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Fig.10 A phase noise waveform diagram of a 7 GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Fig.11 The phase noise waveform of the 8GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification, Fig.12 A phase noise waveform diagram of a 9 GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Fig.13 A phase noise waveform diagram of a 10 GHz output signal of a broadband fine-step low phase noise signal generation system provided in an embodiment of this specification, Fig.14 The phase noise waveform of the 11GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification, Fig.15 A phase noise waveform diagram of a 12 GHz output signal of a broadband fine-step low phase noise signal generation system provided in one embodiment of this specification;

[0049] The system also includes an amplitude detection module, which is used to perform amplitude detection on a cross-octave small-step frequency reference signal. After the amplitude detection, the signal is fed back to the control unit. The control unit also controls the SPDT switch, the switch filter group, and the digitally controlled attenuator to achieve reasonable distribution of amplifiers and attenuators, ensure that the signal power at various locations in the channel is not too small, ensure that the amplifier and attenuator work in the linear region, ensure that the signal power at various locations on the link is not too low, avoid deteriorating the absolute noise floor of -174dBm / Hz, and achieve low phase noise;

[0050] The system further comprises a temperature monitoring module configured to detect temperature sensitive parts of the amplifier, and after the temperature detection, a signal is fed back to the control unit for monitoring the temperature status of the system;

[0051] In terms of structural design, slotting is used to reduce the impact of spatial crosstalk between channels to ensure good channel closure, and the circuits are shielded with covers to ensure that they are not interfered with by the outside world.

[0052] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the system described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0053] It should be noted that the broadband fine-step low phase noise signal generation system provided in the above embodiment is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the modules or steps, and are not regarded as improper limitations of the present invention.

[0054] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A broadband fine-step low phase noise signal generation system, characterized in that: The system includes an intermediate frequency filter selection module, a mixing filter selection module, and an amplification output module; The intermediate frequency filter selection module is configured to receive a DDS reference signal and an external intermediate frequency input signal as input signals; input the input signal into the SPDT switch for selection, and input the selected signal into the first switch filter group for segmented filtering processing, and output signals within multiple frequency ranges; The mixing filter selection module is configured to receive the point frequency local oscillator signal from the external input local oscillator generating unit and the signal within the multiple frequency ranges; the signal within the multiple frequency ranges and the point frequency local oscillator signal are processed by the attenuator and the power amplifier respectively and then input into the mixer for mixing; The mixed signal is subjected to switch filtering by the second switch filter group and then output; The amplification output module is configured to receive the signal output by the second switch filter group, and process it through a power amplifier, a digitally controlled attenuator, and a coupler in sequence to obtain a frequency reference signal with a small step across an octave.

2. A broadband fine-step low phase noise signal generation system according to claim 1, characterized in that: The frequency range of the DDS reference signal is 500-1000MHz; the frequency range of the external intermediate frequency input signal is 500-1000MHz; the signal within the multi-segment frequency range is a signal within a 3-segment frequency range; the frequency range of the cross-octave small step frequency reference signal is 6.0GHz-12.0GHz.

3. A broadband fine-step low phase noise signal generation system according to claim 1, characterized in that: The point-frequency local oscillator signal is within the range of 6.0 GHz to 12.0 GHz, and fills the signals within the multiple frequency ranges according to the set frequency step of 1 GHz.

4. A broadband fine-step low phase noise signal generation system according to claim 1, characterized in that: The SPDT switch comprises a high isolation switch.

5. The broadband fine-step low phase noise signal generating system according to claim 1, characterized in that: The first switching filter group includes three filters, respectively serving as a first filter, a second filter, and a third filter; the first filter is used to filter the input signal in a frequency band of 500 to 650 MHz; the second filter is used to filter the input signal in a frequency band of 550 to 800 MHz; the third filter is used to filter the input signal in a frequency band of 700 to 1000 MHz.

6. A broadband fine-step low phase noise signal generation system according to claim 1, characterized in that: The amplifier, the attenuator and the digitally controlled attenuator all operate in a linear region.

7. A broadband fine-step low phase noise signal generation system according to claim 1, characterized in that: The circuit structure of the system adopts a slotted manner; the circuit of the system adopts a cover plate for shielding.

8. A broadband fine-step low phase noise signal generation system according to claim 1, characterized in that: The system also includes an amplitude detection module and a temperature monitoring module; The amplitude detection module is configured to perform amplitude detection on the cross-octave small-step frequency reference signal, and the signal after amplitude detection is fed back to the control unit; The temperature monitoring module is configured to detect the temperature sensitive parts of the amplifier, and the signal after the temperature detection is fed back to the control unit.

9. A broadband fine-step low phase noise signal generating system according to claim 8, characterized in that: The control unit controls the SPDT switch, the switch filter group, and the digitally controlled attenuator.

10. A broadband fine-step low phase noise signal generation system according to claim 6, characterized in that: The digital controlled attenuator is a programmable attenuator used for performing precise attenuation control on a signal.

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