Broadband low-phase-noise small-step frequency source

Abstract

The utility model discloses a broadband low-phase-noise small-step frequency source, which comprises a large step ring and a small step ring, and is characterized in that the large step ring comprises a first power divider, a frequency multiplier, a first frequency mixer, a second power divider, a first voltage-controlled oscillator and a first phase discriminator; and the small step ring comprises a direct digital frequency synthesizer, a second phase discriminator, a second frequency mixer, a third power divider, a loop filter, a second voltage-controlled oscillator and a programmable frequency divider. According to the utility model, a reference signal is divided into three paths of reference signals after being subjected to power division by the first power divider, and the three paths of reference signals are respectively sent to the frequency multiplier, the first phase discriminator and the direct digital frequency synthesizer, so that the homology of the whole circuit is ensured; a broadband low-phase-noise small-stepping signal is generated through multi-stage frequency doubling and phase locking of the large stepping ring and the small stepping ring and a digital frequency synthesis device, and no fractional stray exists, so that the problems that the frequency coverage is not wide enough, the fractional stray exists, and the phase noise is large are solved.

Description

Technical Field

[0001] This utility model relates to the field of wireless communication technology, specifically to a broadband low phase noise small step frequency source. Background Technology

[0002] A broadband low phase noise small step frequency source is a frequency synthesizer with technical specifications such as wide bandwidth, low phase noise, and small step size. This type of frequency synthesizer has wide applications in radar and communication systems, and its performance directly affects the system performance. The broadband low phase noise small step frequency source is mainly used to generate signals with a frequency range of 1GHz-16GHz and a step size of 1Hz, providing local oscillators for RF transceiver systems, RF signals for test systems, and system clocks, etc.

[0003] However, in practical use, existing frequency sources have some defects, such as insufficient frequency coverage, fractional spurious emissions, and relatively high phase noise. Utility Model Content

[0004] The purpose of this invention is to provide a broadband, low phase noise, small step frequency source to solve the problems of insufficient frequency coverage, fractional spurious emissions, and high phase noise in existing frequency sources.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a broadband low phase noise small step frequency source, comprising a large step loop and a small step loop, wherein the large step loop includes:

[0006] The system comprises a first power divider, a frequency multiplier, a first mixer, a second power divider, a first voltage-controlled oscillator, and a first phase detector.

[0007] The small stepping loop includes a direct digital frequency synthesizer, a second phase detector, a second mixer, a third power divider, a loop filter, a second voltage-controlled oscillator, and a programmable frequency divider;

[0008] The large stepping loop and the small stepping loop work together with the reference signal to output a wideband, low-phase-noise, small-stepping signal.

[0009] Preferably, the first power divider is connected to the frequency multiplier, the first phase detector, and the direct digital frequency synthesizer, the frequency multiplier is connected to the first mixer, and the first mixer is connected to the second power divider and the first phase detector, the first voltage-controlled oscillator is connected to the second power divider and the first phase detector, and the second power divider is connected to the second mixer.

[0010] Preferably, the second phase detector is connected to the direct digital frequency synthesizer, the second mixer, and the loop filter, respectively, and the third power divider is connected to the second mixer, the second voltage-controlled oscillator, and the programmable frequency divider, respectively.

[0011] Preferably, the first power divider is used to divide the reference signal into three reference signals, and the frequency multiplier is used to form a low phase noise signal from one of the reference signals of the first power divider, and connect it with the first mixer, the second power divider, the first voltage-controlled oscillator and the first phase detector to generate a low phase noise broadband signal. The first voltage-controlled oscillator receives the signal transmitted by the first phase detector and generates a broadband signal.

[0012] Preferably, the first mixer is used to receive the output signal of the first voltage-controlled oscillator transmitted by the second power divider, and to feed back to the first phase detector that the function of generating a wideband low phase noise signal by a large stepping loop has been achieved.

[0013] Preferably, the second mixer receives the broadband signal from the second voltage-controlled oscillator transmitted by the third power divider and mixes it with the broadband low-phase-noise signal generated by the large-step loop before feeding it back to the second phase detector. The direct digital frequency synthesizer is used to generate a small-step signal based on one reference signal from the first power divider and send it to the second phase detector. The second phase detector is used to generate a control signal based on the mixing signal transmitted by the second mixer and the small-step signal transmitted by the direct digital frequency synthesizer, and transmits it to the second voltage-controlled oscillator through a loop filter. The second voltage-controlled oscillator is used to generate a broadband low-phase-noise small-step signal based on the control signal from the second phase detector transmitted by the loop filter, covering a frequency range of 1-16 GHz.

[0014] Preferably, the frequency of the reference signal is 100MHz, the frequency of the low phase noise signal generated by the frequency multiplier covers 1.5-3GHz, and the output signal of the frequency multiplier is fed back to the first phase detector after being mixed with the signal of the first voltage-controlled oscillator. The first phase detector outputs a voltage-controlled voltage to control the first voltage-controlled oscillator to output the corresponding frequency, and the low phase noise large step ring output frequency of the large step ring covers 1.8-3.8GHz.

[0015] Preferably, the small stepping ring feeds back the mixed signal from the output signal of the large stepping ring to the second phase detector and the small stepping signal generated by the direct digital frequency synthesizer, and finally generates a broadband low phase noise small stepping signal of the small stepping ring. The final output frequency range of the small stepping ring covers 1-16GHz, and the minimum step reaches 1Hz.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. This utility model divides the reference signal into three reference signals after it is divided into three channels by the first power divider. These channels are then fed into the frequency multiplier, the first phase detector, and the direct digital frequency synthesizer, respectively. This ensures the homogeneity of the entire circuit. Through multi-stage frequency multiplication, phase locking, and digital frequency synthesis devices with large and small step loops, a wideband, low phase noise, and small step signal is generated. Furthermore, there are no fractional spurious signals, thus avoiding problems such as insufficient frequency coverage, fractional spurious signals, and high phase noise. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the broadband low phase noise small step frequency source of this utility model.

[0019] In the diagram: 1. First power divider; 2. Frequency multiplier; 3. First mixer; 4. Second power divider; 5. First voltage-controlled oscillator; 6. First phase detector; 7. Direct digital frequency synthesizer; 8. Second phase detector; 9. Second mixer; 10. Third power divider; 11. Loop filter; 12. Second voltage-controlled oscillator; 13. Programmable frequency divider. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Please see Figure 1 This utility model provides a technical solution: a broadband low phase noise small step frequency source, including a large step loop and a small step loop, wherein the large step loop includes:

[0022] The system comprises a first power divider 1, a frequency multiplier 2, a first mixer 3, a second power divider 4, a first voltage-controlled oscillator 5, and a first phase detector 6. The first power divider 1 is connected to the frequency multiplier 2, the first phase detector 6, and the direct digital frequency synthesizer 7. The frequency multiplier 2 is connected to the first mixer 3, and the first mixer 3 is connected to the second power divider 4 and the first phase detector 6. The first voltage-controlled oscillator 5 is connected to the second power divider 4 and the first phase detector 6. The second power divider 4 is connected to the second mixer 9.

[0023] The small stepping loop includes a direct digital frequency synthesizer 7, a second phase detector 8, a second mixer 9, a third power divider 10, a loop filter 11, a second voltage-controlled oscillator 12, and a programmable frequency divider 13. The second phase detector 8 is connected to the direct digital frequency synthesizer 7, the second mixer 9, and the loop filter 11. The third power divider 10 is connected to the second mixer 9, the second voltage-controlled oscillator 12, and the programmable frequency divider 13. The first power divider 1 is used to divide the reference signal into three reference signals. The frequency multiplier 2 is used to form a low-phase-noise signal from one of the reference signals from the first power divider 1, and connects it to the first mixer 3, the second power divider 4, the first voltage-controlled oscillator 5, and the first phase detector 6 to generate a low-phase-noise broadband signal. The first voltage-controlled oscillator 5 receives the signal transmitted from the first phase detector 6 and generates a broadband signal. The first mixer 3 receives the output signal of the first voltage-controlled oscillator 5 transmitted from the second power divider 4 and feeds back to the first phase detector 6 that the large stepping loop has achieved broadband low-phase-noise generation. The function of the noise signal is as follows: the second mixer 9 receives the broadband signal from the second voltage-controlled oscillator 12 transmitted by the third power divider 10 and mixes it with the broadband low phase noise signal generated by the large step loop, and then feeds it back to the second phase detector 8. The direct digital frequency synthesizer 7 receives one 100MHz reference signal from the first power divider 1 and generates a small step reference signal. The frequency word of the direct digital frequency synthesizer 7 is 48 bits, and the minimum frequency step is about 3.55mHz, which meets the requirement of a minimum step of 1Hz. The direct digital frequency synthesizer 7 sends the small step reference signal to the second phase detector 8. The second phase detector 8 is used to generate a control signal based on the mixing signal transmitted by the second mixer 9 and the small step signal transmitted by the direct digital frequency synthesizer 7. The control signal is transmitted to the second voltage-controlled oscillator 12 through the loop filter 11. The second voltage-controlled oscillator 12 is used to generate a broadband low phase noise small step signal based on the control signal of the second phase detector 8 transmitted by the loop filter 11, covering a frequency range of 1-16GHz.

[0024] The large stepping loop and the small stepping loop work together with the reference signal to output a wideband, low phase noise, small stepping signal.

[0025] The reference signal frequency is 100MHz. The low phase noise signal generated by frequency multiplier 2 covers a frequency range of 1.5-3GHz. The output signal of frequency multiplier 2 is mixed with the signal of the first voltage-controlled oscillator 5 and fed back to the first phase detector 6. The first phase detector 6 outputs a voltage-controlled voltage to control the first voltage-controlled oscillator 5 to output the corresponding frequency. The low phase noise output frequency of the large step ring covers a frequency range of 1.8-3.8GHz. The small step ring feeds back the signal after mixing the output signal of the large step ring with the output signal of the small step ring to the second phase detector 8 for phase detection with the small step signal generated by the direct digital frequency synthesizer 7. Finally, a broadband low phase noise small step signal of the small step ring is generated. The final output frequency range of the small step ring covers a frequency range of 1-16GHz, with a minimum step of 1Hz.

[0026] The specific process described above is as follows: After receiving a 100MHz reference signal from the first power divider 1, the frequency multiplier 2 generates multiple low-phase-noise signals covering 1.5-3.5GHz. These signals are then mixed with the signal generated by the first voltage-controlled oscillator 5 (transmitted by the second power divider 4) at the first mixer 3, generating a 300-800MHz signal that is fed back to the first phase detector 6. The first phase detector 6 compares this signal with the 100MHz reference signal to generate a control signal, which is then sent to the first voltage-controlled oscillator 5. The first voltage-controlled oscillator 5 generates a corresponding wideband low-phase-noise signal and sends it to the first phase detector 6. The wideband low phase noise signal from the small-step loop and the large-step loop are mixed with the signal from the third power divider 10 at the second mixer 9 to generate a feedback signal to the second phase detector 8. This feedback signal is compared with the small-step reference signal generated from the direct digital frequency synthesizer 7 to generate a control signal. The control signal passes through the loop filter 11 to the second voltage-controlled oscillator 12. The second voltage-controlled oscillator 12 generates a wideband low phase noise small-step signal and sends it to the third power divider 10. The frequency range of this signal is 8-16GHz. In addition, this embodiment has no fractional N value, so no fractional spurious signals are generated.

[0027] In summary, in the broadband low phase noise small step frequency source provided by this utility model, the reference signal is divided into three reference signals after passing through the first power divider 1. These signals enter the frequency multiplier 2, the first phase detector 6, and the direct digital frequency synthesizer 7, respectively. After frequency multiplication and phase detection, the first stage of the large step loop is first generated as a broadband low phase noise signal. This signal enters the small step loop and passes through the direct digital frequency synthesizer 7, the second phase detector 8, the second mixer 9, the third power divider 10, the loop filter 11, and the second voltage-controlled oscillator 12 to generate the final broadband low phase noise small step frequency source. There are no fractional spurious signals, thus avoiding the problems of insufficient frequency coverage, fractional spurious signals, and large phase noise.

[0028] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. Broadband low phase noise small step frequency source, including large step loop and small step loop, characterized by: The large step loop comprises: A first power divider (1), a frequency multiplier (2), a first mixer (3), a second power divider (4), a first voltage-controlled oscillator (5) and a first phase detector (6); The small step loop comprises a direct digital frequency synthesizer (7), a second phase detector (8), a second mixer (9), a third power divider (10), a loop filter (11), a second voltage-controlled oscillator (12) and a programmable frequency divider (13); The large step loop and the small step loop cooperate with the reference signal to output a broadband low phase noise small step signal.

2. The broadband low phase noise small step frequency source according to claim 1, characterized in that: The first power divider (1) is respectively connected to a frequency multiplier (2), a first phase detector (6) and a direct digital frequency synthesizer (7); the frequency multiplier (2) is connected to a first mixer (3); and the first mixer (3) is respectively connected to a second power divider (4) and a first phase detector (6); the first voltage-controlled oscillator (5) is respectively connected to a second power divider (4) and a first phase detector (6); and the second power divider (4) is connected to a second mixer (9).

3. The broadband low phase noise small step frequency source according to claim 1, characterized in that: The second phase detector (8) is respectively connected to the direct digital frequency synthesizer (7), the second mixer (9) and the loop filter (11), and the third power divider (10) is respectively connected to the second mixer (9), the second voltage-controlled oscillator (12) and the programmable frequency divider (13).

4. The broadband low phase noise small step frequency source according to claim 1, characterized in that: The first power divider (1) is used to divide the reference signal into three reference signals; the frequency multiplier (2) is used to convert one reference signal of the first power divider (1) into a signal with low phase noise, and is connected with the first mixer (3), the second power divider (4), the first voltage-controlled oscillator (5) and the first phase detector (6) to generate a broadband signal with low phase noise; the first voltage-controlled oscillator (5) receives the signal transmitted by the first phase detector (6) and generates a broadband signal.

5. The broadband low phase noise small step frequency source according to claim 1, characterized in that: The first mixer (3) is used to receive the output signal of the first voltage-controlled oscillator (5) transmitted by the second power divider (4), and to feed back the output signal to the first phase detector (6) to achieve the function of generating a broadband low phase noise signal in a large step loop.

6. The broadband low phase noise small step frequency source according to claim 1, characterized in that: The second mixer (9) receives the broadband signal of the second voltage-controlled oscillator (12) transmitted by the third power divider (10), mixes it with the broadband low phase noise signal generated by the large step loop, and then feeds it back to the second phase detector (8); the direct digital frequency synthesizer (7) is used to generate a small step signal according to a reference signal of the first power divider (1) and send it to the second phase detector (8); the second phase detector (8) is used to generate a control signal according to the mixing signal transmitted by the second mixer (9) and the small step signal transmitted by the direct digital frequency synthesizer (7), and transmit it to the second voltage-controlled oscillator (12) through the loop filter (11); the second voltage-controlled oscillator (12) is used to generate a broadband low phase noise small step signal according to the control signal transmitted by the loop filter (11) to the second phase detector (8), covering a frequency range of 1-16 GHz.

7. The broadband low phase noise small step frequency source according to claim 1, characterized in that: The frequency of the reference signal is 100 MHz, the frequency of the low phase noise signal generated by the frequency multiplier (2) covers 1.5-3 GHz, and the output signal of the frequency multiplier (2) and the signal mixed by the first voltage-controlled oscillator (5) are fed back to the first phase detector (6), the first phase detector (6) outputs a voltage-controlled voltage to control the first voltage-controlled oscillator (5) to output a corresponding frequency, and the low phase noise large-step ring output frequency generated by the large-step ring covers 1.8-3.8 GHz.

8. The broadband low phase noise small step frequency source according to claim 1, characterized in that: The small step ring feeds back the mixed signal of the output signal of the large step ring and the output signal of the small step ring to the second phase detector (8) and the small step signal generated by the direct digital frequency synthesizer (7) for phase detection, and finally generates a broadband low phase noise small step signal of the small step ring. The final output frequency range of the small step ring covers 1-16GHz, and the minimum step reaches 1Hz.

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