Low-jitter ultra-wideband pulse signal generator and pulse signal generation method

Abstract

The invention provides a low-jitter ultra-wideband pulse signal generator and a pulse signal generation method.The low-jitter ultra-wideband pulse signal generator comprises a crystal oscillator, a power divider, a local oscillator signal path, an intermediate frequency signal path and a wideband mixer, the power divider is used for dividing a reference frequency signal into two paths and respectively sending the two paths to a local oscillator signal path and an intermediate frequency signal path, an absorption type band-pass filter in the local oscillator signal path is used for outputting a local oscillator signal of a target frequency, and an absorption type high-pass filter in the intermediate frequency signal path is used for outputting an ultra-wideband intermediate frequency signal; the broadband mixer is used for mixing the local oscillator signal and the intermediate frequency signal to output an ultra-wideband pulse signal with the center frequency as the target frequency, and it is ensured that the output signal has the low jitter characteristic and the high signal-to-noise ratio.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of ultra-wideband pulse signals, and in particular to a low-jitter ultra-wideband pulse signal generator and a pulse signal generating method. Background Art

[0002] At present, ultra-wideband (UWB) pulse signals have been widely used in fields such as communications and radar due to their large instantaneous bandwidth. The existing UWB signal generation technologies mainly include the following methods:

[0003] High-speed digital-to-analog converter (DAC): Use high-speed DAC to generate ultra-wideband pulse signals in the Nyquist zone. The advantage of this method is that the phase and amplitude are controllable, which is suitable for high-order modulation transmission in digital communication, but the bandwidth is limited (about 0.4 times the sampling rate), the power consumption is large, and the logic resource overhead is large.

[0004] Relaxation oscillator: Designed and manufactured based on microelectronics technology, it is suitable for generating UWB signals under precision process conditions. This type of oscillator has extremely high process requirements and is difficult to implement in conventional board-level circuits. The generated signal has a small bandwidth and large jitter, and is usually used for low-precision ranging and short-distance communication.

[0005] RF transistor: Use a frequency reference source to drive the RF transistor to generate a highly nonlinear ultra-wideband pulse signal. The advantages of this method are wide bandwidth and moderate phase noise, but low efficiency and non-adjustable center frequency. It is suitable for industrial radars such as waveguides.

[0006] In summary, the existing ultra-wideband pulse signal generator has large jitter and the center frequency cannot be adjusted, which leads to poor signal-to-noise ratio of ultra-wideband pulse signals, inconvenience of antenna transmission and reception, and low detection accuracy. Summary of the invention

[0007] An embodiment of the present invention provides a low-jitter ultra-wideband pulse signal generator, which can mix a local oscillator signal and an intermediate frequency signal to output an ultra-wideband pulse signal with a center frequency as a target frequency, and can ensure that the output signal has a low-jitter characteristic to maintain a high signal-to-noise ratio of the signal.

[0008] To achieve the above-mentioned purpose, an embodiment of the present invention provides a low-jitter ultra-wideband pulse signal generator, comprising: a crystal oscillator; a power divider, wherein the input end of the power divider is connected to the crystal oscillator; a local oscillator signal path, comprising an absorptive bandpass filter, wherein the input end of the local oscillator signal path is connected to the first output end of the power divider; an intermediate frequency signal path, comprising an absorptive high-pass filter, wherein the input end of the local oscillator signal path is connected to the second output end of the power divider; and a broadband mixer, wherein the input end of the broadband mixer is respectively connected to the output ends of the local oscillator signal path and the intermediate frequency signal path; wherein the crystal oscillator is used to output a reference frequency signal, the power divider is used to divide the reference frequency signal into two paths and send them to the local oscillator signal path and the intermediate frequency signal path respectively, the absorptive bandpass filter in the local oscillator signal path is used to output a local oscillator signal of a target frequency, the absorptive high-pass filter in the intermediate frequency signal path is used to output an ultra-wideband intermediate frequency signal, and the broadband mixer is used to mix the local oscillator signal and the intermediate frequency signal to output an ultra-wideband pulse signal with a center frequency of the target frequency.

[0009] In some embodiments, the local oscillator signal path further includes an M frequency divider, a first low phase noise amplifier and a first comb generator, and the M frequency divider, the first low phase noise amplifier, the first comb generator and the absorptive bandpass filter are cascaded in sequence.

[0010] In some embodiments, the local oscillator signal path further includes an N frequency divider, a second low phase noise amplifier and a second comb generator, and the N frequency divider, the first low phase noise amplifier, the second comb generator and the absorptive high-pass filter are cascaded in sequence.

[0011] In some embodiments, the target frequency is f ref , the frequency multiplication factor of the local oscillator signal path is L, the frequency division ratio of the M divider is M, and the target frequency of the local oscillator signal is

[0012] In some embodiments, the target frequency is f ref , the division ratio of the N divider is N, and the frequency of the intermediate frequency signal is

[0013] In some embodiments, the target frequency is f ref , the frequency multiplication factor of the local oscillator signal path is L, the frequency division ratio of the M frequency divider is M, the frequency division ratio of the N frequency divider is N, and the frequency of the ultra-wideband pulse signal is

[0014]

[0015] In some embodiments, the division ratio of the M frequency divider is 1, the division ratio of the N frequency divider is 10, and each device in the local oscillator signal path and the intermediate frequency signal path is configured with low additional time jitter as the goal.

[0016] In some embodiments, the local oscillator signal path is cascaded with a low phase noise local oscillator amplifier, so that the local oscillator signal power corresponding to the local oscillator signal path is within a preset device local oscillator rated power range.

[0017] In some embodiments, an output end of the ultra-wideband pulse signal generator is provided with an absorptive filter or attenuator, and the absorptive filter or attenuator is provided according to the impedance matching of the ultra-wideband pulse signal generator.

[0018] To achieve the above-mentioned purpose, an embodiment of the present invention provides a method for generating an ultra-wideband pulse signal. The method is applied to a wideband pulse generator as described in any one of the above-mentioned embodiments, and the method includes: adjusting the device configuration parameters in the local oscillator signal path to change the center frequency of the ultra-wideband pulse signal; adjusting the device configuration parameters in the intermediate frequency signal path to change the bandwidth of the ultra-wideband pulse signal.

[0019] The low-jitter ultra-wideband pulse signal generator provided by the embodiment of the present invention can provide a reference frequency signal through a crystal oscillator, and this signal is the basis for all subsequent processing; further, the reference frequency signal from the crystal oscillator is divided into two equal-amplitude signals through a power divider, and the two signals are then sent to different signal processing paths. The use of the power divider ensures the coherence of the two signals; further, a single-tone signal of the target frequency is extracted from one signal output by the power divider through an absorptive bandpass filter in the local oscillator signal path, and this signal will be used as a local oscillator (LO) signal. The bandpass filter can ensure that the local oscillator signal has the required frequency characteristics and low phase noise, thereby improving the spectral purity and reducing the jitter of the output signal; further, an absorptive high-pass filter in the intermediate frequency signal path is used to extract a single-tone signal of the target frequency from another signal output by the power divider. An ultra-wideband intermediate frequency signal is generated in the signal, and the selection of the high-pass filter makes the signal contain a wide range of frequency components, so that when mixed with the local oscillator signal, an ultra-wideband pulse signal with the required bandwidth characteristics will be generated; further, the signals generated by the above two paths are merged, and the local oscillator signal and the intermediate frequency signal are nonlinearly combined to generate a new signal frequency combination. Since the local oscillator signal has a low jitter characteristic, and the intermediate frequency signal has low jitter and broadband characteristics, the ultra-wideband pulse signal finally output will also inherit these advantages. Through the above design, the present invention ensures that the time jitter is minimized in the entire process from reference signal generation to the final output signal, so that the ultra-wideband pulse signal finally output has a high signal-to-noise ratio, which makes the generator of the present application suitable for occasions requiring high-precision, low-jitter signals, such as high-precision near-field detection, perception and ranging applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A circuit diagram of a low-jitter ultra-wideband pulse signal generator provided by an embodiment of the present invention;

[0021] Figure 2 A time domain waveform diagram of a low-jitter ultra-wideband pulse signal with multiple cycles provided by an embodiment of the present invention;

[0022] Figure 3 A time domain waveform diagram of a low-jitter ultra-wideband pulse signal within a period provided by an embodiment of the present invention;

[0023] Figure 4 A spectrum diagram of a low-jitter ultra-wideband pulse signal provided by an embodiment of the present invention;

[0024] Figure 5 A spectrum diagram of a low-jitter ultra-wideband pulse signal within a 100 MHz bandwidth provided by an embodiment of the present invention;

[0025] Figure 6This is a phase noise diagram of a low-jitter ultra-wideband pulse signal at a 4.1 GHz carrier provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] In some embodiments, although the functional modules are divided in the system schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flowchart. The terms first, second, etc. in the specification, claims and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0028] In addition, unless otherwise clearly specified and limited, the term "connected" should be understood in a broad sense. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or the two can communicate with each other; it can be a direct connection or an indirect connection through an intermediate medium.

[0029] In the description of the embodiments of the present invention, the description with reference to the terms "one embodiment / implementation", "another embodiment / implementation" or "certain embodiments / implementations", "in the above embodiments / implementations", etc. means that the specific features, structures, materials or characteristics described in combination with the embodiments or examples are included in at least two embodiments or implementations disclosed in the present invention. In the disclosure of the present invention, the schematic representation of the above terms does not necessarily refer to the same embodiment or implementation. It should be noted that although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in an order different from that in the flowchart.

[0030] At present, ultra-wideband (UWB) pulse signals have been widely used in fields such as communications and radars due to their large instantaneous bandwidth. The existing UWB signal generation technologies mainly include the following methods: High-speed digital-to-analog converter (DAC): Use high-speed DAC to generate ultra-wideband pulse signals in the Nyquist zone. The advantage of this method is that the phase and amplitude are controllable, which is suitable for high-order modulation transmission in digital communication, but the bandwidth is limited (about 0.4 times the sampling rate), and the power consumption is large, and the logic resource overhead is large. Relaxation oscillator: Designed and manufactured based on microelectronics technology, it is suitable for generating UWB signals under precision process conditions. This type of oscillator has extremely high process requirements and is difficult to implement in conventional board-level circuits. The generated signal bandwidth is small and the jitter is large. It is usually used for ranging and short-distance communication with low accuracy. RF transistor: Use a certain frequency reference source to drive the RF transistor to generate a strongly nonlinear ultra-wideband pulse signal. The advantage of this method is that the bandwidth is wide and the phase noise is moderate, but the efficiency is low and the center frequency is not adjustable. It is suitable for industrial radars such as waveguides.

[0031] In summary, the existing ultra-wideband pulse signal generator has large jitter and the center frequency cannot be adjusted, which leads to poor signal-to-noise ratio of ultra-wideband pulse signals, inconvenience of antenna transmission and reception, and low detection accuracy.

[0032] Based on this, an embodiment of the present invention provides a low-jitter ultra-wideband pulse signal generator, which can mix a local oscillator signal and an intermediate frequency signal to output an ultra-wideband pulse signal with a center frequency as a target frequency, and can ensure that the output signal has a low-jitter characteristic to improve the signal-to-noise ratio and transceivability of the signal.

[0033] refer to Figure 1 , Figure 1A circuit diagram of a low-jitter ultra-wideband pulse signal generator provided by an embodiment of the present invention. The present invention provides a low-jitter ultra-wideband pulse signal generator. To achieve the above-mentioned purpose, an embodiment of the present invention provides a low-jitter ultra-wideband pulse signal generator, including: a crystal oscillator; a power divider, the input end of the power divider is connected to the crystal oscillator; a local oscillator signal path, including an absorptive bandpass filter, the input end of the local oscillator signal path is connected to the first output end of the power divider; an intermediate frequency signal path, including an absorptive high-pass filter, the input end of the local oscillator signal path is connected to the second output end of the power divider The broadband mixer is connected to the local oscillator signal path and the intermediate frequency signal path respectively; wherein the crystal oscillator is used to output a reference frequency signal, the power divider is used to divide the reference frequency signal into two paths and send them to the local oscillator signal path and the intermediate frequency signal path respectively, the absorptive bandpass filter in the local oscillator signal path is used to output a local oscillator signal of a target frequency, the absorptive high-pass filter in the intermediate frequency signal path is used to output an ultra-wideband intermediate frequency signal, and the broadband mixer is used to mix the local oscillator signal and the intermediate frequency signal to output an ultra-wideband pulse signal with a center frequency of the target frequency.

[0034] Among them, the present application can provide a reference frequency signal through a crystal oscillator, and this signal is the basis for all subsequent processing; further, the reference frequency signal from the crystal oscillator is divided into two equal-amplitude signals through a power divider, and the two signals are then sent to different signal processing paths. The use of the power divider ensures the coherence of the two signals; further, a single-tone signal of the target frequency is extracted from one signal output by the power divider through an absorptive bandpass filter in the local oscillator signal path, and this signal will be used as a local oscillator (LO) signal. The bandpass filter can ensure that the local oscillator signal has the required frequency characteristics and low phase noise, thereby reducing the jitter of the output signal; further, an ultra-wideband intermediate frequency signal is generated from another signal output by the power divider through an absorptive high-pass filter in the intermediate frequency signal path. The selection of the high-pass filter makes the signal contain a wide range of frequency components, so that when mixed with the local oscillator signal, an ultra-wideband pulse signal with the required bandwidth characteristics will be generated; further, the signals generated by the above two paths are merged, and the local oscillator signal and the intermediate frequency signal are nonlinearly combined to generate a new signal frequency combination. Since the local oscillator signal has a low jitter characteristic and the intermediate frequency signal has a wideband and low jitter characteristic, the ultra-wideband pulse signal finally output will also inherit these advantages. Through the above design, the present invention ensures that the jitter is minimized in the entire process from reference signal generation to the final output signal, so that the ultra-wideband pulse signal finally output has a high signal-to-noise ratio, which makes the generator of the present application suitable for occasions requiring high-precision, low-jitter signals, such as high-precision near-field detection, perception and ranging applications.

[0035] Among them, the local oscillator signal path needs to generate a narrowband signal with a relatively narrow frequency range. In this case, the use of an absorptive bandpass filter can effectively filter out unwanted frequency components and only retain signals near the target frequency. This filter is designed to provide a very narrow bandwidth to ensure the purity and accuracy of the local oscillator signal. The narrowband local oscillator signal is beneficial to the subsequent mixing process because it can be better mixed with the intermediate frequency signal to generate the required RF signal; the intermediate frequency signal path needs to generate an ultra-wideband signal with a relatively wide frequency range. In this case, the use of an absorptive high-pass filter can filter out low-frequency components and only retain the high-frequency part. This is because ultra-wideband pulse signals usually contain multiple frequency components and have a wide frequency range. The high-pass filter can help this application obtain signals within the required frequency range while eliminating unnecessary low-frequency components, thereby generating an intermediate frequency signal with sufficient bandwidth; therefore, the local oscillator signal and the intermediate frequency signal have different uses. The local oscillator signal is mainly used in the mixing process to generate the radio frequency signal, while the intermediate frequency signal is the result of mixing, which includes various frequency components obtained from the mixing of the local oscillator signal and the intermediate frequency signal. Therefore, according to different signal characteristics, selecting the corresponding filter type can better meet their respective purposes and application requirements.

[0036] In some embodiments, the local oscillator signal path further includes an M frequency divider, a first low phase noise amplifier, and a first comb generator, and the M frequency divider, the first low phase noise amplifier, the first comb generator, and the absorptive bandpass filter are cascaded in sequence. Figure 1 The medium and low phase noise amplifier 1 is the first low phase noise amplifier, and the low phase noise amplifier 1 is the first comb spectrum generator.

[0037] In some embodiments, the target frequency is f ref , the multiplication factor of the local oscillator signal path is L, the division ratio of the M divider is M, and the target frequency of the local oscillator signal is Wherein, L is a frequency multiplication factor for adjusting the frequency of the final output local oscillator signal (LO). L is related to the frequency adjustment. When the first comb generator includes a frequency multiplication function, the size of L can be achieved by adjusting the design parameters of the comb generator.

[0038] Among them, the M divider is a digital circuit whose main function is to reduce the frequency of the input signal by M times. For example, if the frequency of the input signal is fref, then after passing through the M divider, the frequency of the output signal will become fref / M. Here M can be a positive integer or a decimal, depending on actual needs. The function of the M divider is to convert the high-frequency signal output by the crystal oscillator into a frequency that is easier to process for subsequent signal processing.

[0039] The function of the low phase noise amplifier is to amplify the signal while minimizing the introduced phase noise. Phase noise refers to the random phase fluctuations in the signal, which will cause the signal quality to deteriorate. The first low phase noise amplifier is located after the M divider to enhance the signal strength while maintaining the purity of the signal as much as possible.

[0040] The comb generator can generate a set of discrete frequency components with fixed frequency intervals between these components. In this embodiment, the low phase noise amplifier 1 is the first comb generator. The function of the comb generator is to add more frequency components in the local oscillator signal path to expand the spectrum of the signal so that it covers a wider frequency range.

[0041] The absorptive bandpass filter can only allow signals within a specific frequency range to pass through. In this embodiment, it is located after the comb generator to further limit the frequency range of the local oscillator signal, making the frequency of the output signal more concentrated, thereby meeting the target frequency requirement.

[0042] It can be understood that in the above embodiment, the crystal oscillator first outputs a reference frequency signal, and then reduces its frequency to fref / M through the M frequency divider. Next, the signal enters the first low phase noise amplifier for amplification, and then adds more frequency components through the first comb generator. Finally, the signal passes through the absorptive bandpass filter, retaining only the components near the target frequency to form a narrow-band local oscillator signal. This process ensures the purity of the local oscillator, thereby improving the signal-to-noise ratio of the signal.

[0043] In some embodiments, the local oscillator signal path further includes an N frequency divider, a second low phase noise amplifier, and a second comb generator, wherein the N frequency divider, the first low phase noise amplifier, the second comb generator, and the absorptive high-pass filter are connected in cascade in sequence. Figure 1 The medium and low phase noise amplifier 2 is the second low phase noise amplifier, and the low phase noise amplifier 2 is the second comb spectrum generator.

[0044] Among them, the N divider reduces the frequency of the input signal by N times. Here N can also be a positive integer or a decimal, depending on the actual needs. The function of the N divider is to convert the high-frequency signal output by the crystal oscillator into a frequency that is easier to handle for subsequent signal processing.

[0045] The function of the second low phase noise amplifier is similar to that of the first low phase noise amplifier, which is to amplify the signal and minimize the influence of phase noise. The second low phase noise amplifier is located after the N divider to enhance the signal strength while maintaining the purity of the signal.

[0046] The second comb generator is also used to generate a set of discrete frequency components, corresponding to (1+2+3+4+...), and there are fixed frequency intervals between these components. In this embodiment, the low phase noise amplifier 2 is the second comb generator. The function of the second comb generator is to add more frequency components in the intermediate frequency signal path to expand the spectrum of the signal so that it covers a wider frequency range.

[0047] The absorptive high-pass filter is a filter that allows all signals above a certain frequency to pass through. In this embodiment, it is located after the second comb generator to remove low-frequency components and leave high-frequency components, thereby forming an ultra-wideband intermediate frequency signal.

[0048] It can be understood that in the above embodiment, the crystal oscillator first outputs a reference frequency signal, and then reduces its frequency to fref / N through the N frequency divider. Next, the signal enters the second low phase noise amplifier for amplification, and then adds more frequency components through the second comb generator. Finally, the signal passes through the absorptive high-pass filter, retaining only the high-frequency part to form an ultra-wideband intermediate frequency signal. This process ensures that the intermediate frequency signal has rich frequency components, thereby meeting the requirements of ultra-wideband pulse signals.

[0049] It should be noted that the parameters of the N divider and the M divider are different because they correspond to different requirements of the local oscillator signal and the intermediate frequency signal. For example, the local oscillator signal may require a narrow frequency range, while the intermediate frequency signal requires a wider frequency range. By adjusting the values ​​of N and M, the frequency characteristics of the final generated local oscillator signal and intermediate frequency signal can be controlled to meet the needs of different application scenarios.

[0050] In some embodiments, the target frequency is f ref , the division ratio of the N divider is N, and the frequency of the intermediate frequency signal is Among them, due to the action of the comb generator 2 and the absorptive high-pass filter, the frequency of the signal is increased to (1+2+3+4+...) times, (1+2+3+4+...) represents the sum of an infinitely increasing sequence of natural numbers, also called the modulation index. Since this is in a physical system, the actual signal frequency cannot be infinite. Therefore, it should be the sum of a finite number of terms, that is, Sn=(1+2+3+4+...n), where n is the number of terms.

[0051] In some embodiments, the target frequency is f ref , the frequency multiplication factor of the local oscillator signal path is L, the frequency division ratio of the M divider is M, the frequency division ratio of the N divider is N, and the frequency of the ultra-wideband pulse signal is

[0052] In some embodiments, the division ratio of the M divider is 1, the division ratio of the N divider is 10, and each device in the local oscillator signal path and the intermediate frequency signal path is configured with the goal of low additional time jitter, wherein the division ratio of the M divider is set to 1, which means that the reference frequency signal output by the crystal oscillator directly enters the local oscillator signal path without any frequency reduction processing. The advantage of this is that the frequency characteristics of the original signal can be retained to the greatest extent, avoiding additional distortion and phase noise caused by frequency division. The division ratio of the N divider is set to 10, which means that the reference frequency signal output by the crystal oscillator is reduced before entering the intermediate frequency signal path. This design is to generate a relatively low-frequency intermediate frequency signal for subsequent processing and mixing. Lowering the frequency is equivalent to increasing the time period, which helps to detect targets at a longer distance.

[0053] In some embodiments, each device in the local oscillator signal path and the intermediate frequency signal path can be configured with low additional time jitter as the goal in the following ways: in the PCB design stage, the corresponding circuit of the ultra-wideband pulse signal generator is designed according to the routing length and layout to avoid delays and reflections caused by long-distance signal transmission, and a shielding cover is used to protect the local oscillator signal path and the intermediate frequency signal path to reduce electromagnetic interference, ensure that the return path of the power supply and ground wires is unobstructed, and reduce power supply noise; further, the crystal oscillator can be packaged in a constant temperature chamber to ensure that it works in a stable temperature environment, and a thermistor is used to monitor the ambient temperature, and digital temperature compensation can also be performed through a software algorithm; further, a phase-locked loop (PLL) technology can be used to ensure clock synchronization between modules, and a calibration program can be run regularly to detect and correct signal transmission cycle errors, and a low-jitter interface standard can be used, such as selecting a low-additional time jitter LVDS interface to connect various devices to reduce time jitter during signal transmission.

[0054] In some embodiments, a local oscillator signal path is cascaded with a low phase noise local oscillator amplifier so that the local oscillator signal power corresponding to the local oscillator signal path is within a preset device local oscillator rated power range, wherein, in order to ensure the performance of the local oscillator signal path, a low phase noise local oscillator amplifier can be added to the local oscillator signal path. The task of this amplifier is to increase the power of the local oscillator signal while minimizing the introduction of phase noise. In this way, the power of the local oscillator signal can be maintained at an appropriate level, neither overloaded nor too weak, thereby ensuring the stable operation of the entire system.

[0055] In some embodiments, the output end of the ultra-wideband pulse signal generator is provided with an absorption filter or attenuator, and the absorption filter or attenuator is set according to the impedance matching of the ultra-wideband pulse signal generator; it is understandable that the output end of the ultra-wideband pulse signal generator can be equipped with an absorption filter or attenuator. The function of these devices is to adjust the amplitude and frequency response of the signal according to the impedance matching of the ultra-wideband pulse signal generator. The absorption filter can absorb unnecessary frequency components, and the attenuator can reduce the power of the signal to prevent the output signal from being too large to damage the receiving device. By reasonably configuring these devices, the performance of the ultra-wideband pulse signal generator can be optimized and the high signal-to-noise ratio of the signal can be maintained.

[0056] To achieve the above-mentioned purpose, an embodiment of the present invention provides a method for generating an ultra-wideband pulse signal. The method is applied to a wideband pulse generator such as any one of the above-mentioned embodiments, and the method includes: adjusting the device configuration parameters in the local oscillator signal path to change the center frequency of the ultra-wideband pulse signal; adjusting the device configuration parameters in the intermediate frequency signal path to change the bandwidth of the ultra-wideband pulse signal.

[0057] refer to Figures 2 to 6 , Figure 2 A time domain waveform diagram of a low-jitter ultra-wideband pulse signal with multiple cycles provided by an embodiment of the present invention; Figure 3 A time domain waveform diagram of a low-jitter ultra-wideband pulse signal within a period provided by an embodiment of the present invention; Figure 4 A spectrum diagram of a low-jitter ultra-wideband pulse signal provided by an embodiment of the present invention; Figure 5 A spectrum diagram of a low-jitter ultra-wideband pulse signal within a 100 MHz bandwidth provided by an embodiment of the present invention; Figure 6 A phase noise diagram of a low-jitter ultra-wideband pulse signal at a 4.1 GHz carrier provided in an embodiment of the present invention, wherein Scale / Div represents the value represented by each grid, usually referring to the scale in the vertical direction; Ref Level represents the reference level, usually the reference level used in measurement; Center represents the center frequency, that is, the center point frequency of the measurement; Video BW represents the video bandwidth, which refers to the video bandwidth setting of the measuring device, which affects the resolution of the measurement result; Span represents the measurement span, that is, the frequency range of the measurement; StartOffset and Stop Offset represent the start offset and the end offset, respectively, and refer to the start and end measurement frequencies relative to the center frequency.

[0058] In some embodiments, the use process of the present application may include:

[0059] Generate local oscillator signal LO: The crystal oscillator outputs a periodic signal with a reference frequency of fref, which is divided into two paths after passing through the power divider. One of the signals passes through the M divider to reduce the frequency to fref / M. Next, the signal is amplified by the low phase noise amplifier 1, and more frequency components are added through the comb generator 1. Finally, the signal passes through the absorptive bandpass filter, retaining only the components near the target frequency, forming a narrowband local oscillator signal LO with a frequency of fref / L. Here, M can be either integer or fractional division, depending on actual needs.

[0060] Generate intermediate frequency signal IF: Another signal output by the crystal oscillator is sent to another path after passing through the power divider. The signal in this path first passes through the N divider to reduce the frequency to fref / N. Then, the signal is amplified by the low phase noise amplifier 2, and more frequency components are added by the comb generator 2. Finally, the signal passes through the absorptive high-pass filter, retaining only the high-frequency part, forming an ultra-wideband intermediate frequency signal IF with a frequency range of more than fref / N. Here, N can also be integer division or fractional division.

[0061] Mixing generates ultra-wideband pulse signal RF: The local oscillator signal LO and the intermediate frequency signal IF are mixed by a wideband mixer to generate a new radio frequency signal RF. Since the mixer is a nonlinear element, it combines the frequency components of the two signals to generate new frequency components. The frequency range of the final output radio frequency signal RF is an ultra-wideband pulse signal that is centered on the local oscillator signal LO and spreads out to both sides. The characteristics of this signal are a wide frequency range and low jitter characteristics.

[0062] In some embodiments, Figure 1 In the actual design, a 100MHz constant temperature crystal oscillator is used as the reference frequency. After passing through the passive power divider, the reference frequency signal is input into the M divider and the N divider respectively. Among them, the division ratio of the M divider is 1, and the division ratio of the N divider is 10. The amplifier can use ADI's low phase noise amplifier, and the amplified signal is used to excite the comb generator 1. Through a narrow-band absorptive bandpass filter, this application obtains an LO signal with a local oscillator frequency of 7GHz (here L is 70, so 70 multiplied by 100MHz equals 7GHz). After the reference frequency signal passes through the N divider, a signal with a period of 10MHz is obtained. After being amplified by the low phase noise amplifier, the signal is used to excite the comb generator 2, thereby obtaining a periodic narrow pulse signal IF: 10MHz*(1+2+3+4+……). As shown Figure 2 and Figure 3As shown in the figure, the time domain and frequency domain diagrams show this process. The absorptive high-pass filter is used to suppress the 10MHz periodic signal while retaining the high-frequency components. The IF and LO signals are mixed through a wideband mixer, and the power of the LO is set within the rated power range of the device's local oscillator. After mixing, an ultra-wideband pulse signal is obtained at the RF port: like Figure 4 and Figure 5 As shown, with 7 GHz as the center frequency, the measured bandwidth reaches 10 GHz.

[0063] In order to facilitate the testing of phase noise and time jitter, this application uses a narrowband cavity filter with a center frequency of 4.1 GHz to pre-select a 4.1 GHz single-tone signal for amplification and re-filtering. The time jitter measured by the signal analyzer is 74.33 femtoseconds (fs), as shown in Figure 2. Figure 5 Figure 6 As shown in the figure, its time jitter performance is better than that of ordinary phase-locked loops and has the characteristics of low phase noise. According to the radar ranging theory, if 1 nanosecond (ns) corresponds to a distance of 0.15 meters, then the root mean square jitter of 74.33 femtoseconds corresponds to 0.15 meters multiplied by 74.33 femtoseconds multiplied by 10^-6, that is, a ranging uncertainty of 11.15 microns. Considering the actual needs of engineering design, this frequency source can support a ranging accuracy of up to 100 microns. In addition, since this low-jitter broadband pulse signal has a center frequency, it is suitable for both antenna transmission and reception in open space and for use in semi-enclosed electromagnetic environments in waveguides.

[0064] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present invention. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A low-jitter ultra-wideband pulse signal generator, characterized in that: include: Crystal oscillator; A power divider, an input end of which is connected to the crystal oscillator; A local oscillator signal path, comprising an absorptive bandpass filter, wherein an input end of the local oscillator signal path is connected to a first output end of the power divider; an intermediate frequency signal path, comprising an absorptive high-pass filter, wherein the input end of the local oscillator signal path is connected to the second output end of the power divider; A broadband mixer, wherein the input end of the broadband mixer is connected to the output ends of the local oscillator signal path and the intermediate frequency signal path respectively; Among them, the crystal oscillator is used to output a reference frequency signal, the power divider is used to divide the reference frequency signal into two paths and send them to the local oscillator signal path and the intermediate frequency signal path respectively, the absorptive bandpass filter in the local oscillator signal path is used to output the local oscillator signal of the target frequency, the absorptive high-pass filter in the intermediate frequency signal path is used to output an ultra-wideband intermediate frequency signal, and the broadband mixer is used to mix the local oscillator signal and the intermediate frequency signal to output an ultra-wideband pulse signal with a center frequency of the target frequency.

2. The low-jitter ultra-wideband pulse signal generator according to claim 1, characterized in that: The local oscillator signal path further includes an M frequency divider, a first low phase noise amplifier and a first comb generator. The M frequency divider, the first low phase noise amplifier, the first comb generator and the absorptive bandpass filter are cascaded in sequence.

3. The low-jitter ultra-wideband pulse signal generator according to claim 2, characterized in that: The local oscillator signal path further includes an N frequency divider, a second low phase noise amplifier and a second comb generator. The N frequency divider, the first low phase noise amplifier, the second comb generator and the absorptive high-pass filter are cascaded in sequence.

4. The low-jitter ultra-wideband pulse signal generator according to claim 2, characterized in that: The target frequency is f ref , the frequency multiplication factor of the local oscillator signal path is L, the frequency division ratio of the M divider is M, and the target frequency of the local oscillator signal is 5. The low-jitter ultra-wideband pulse signal generator according to claim 3, characterized in that: The target frequency is f ref , the division ratio of the N divider is N, and the frequency of the intermediate frequency signal is 6. The low-jitter ultra-wideband pulse signal generator according to claim 3, characterized in that: The target frequency is f ref , the frequency multiplication factor of the local oscillator signal path is L, the frequency division ratio of the M frequency divider is M, the frequency division ratio of the N frequency divider is N, and the frequency of the ultra-wideband pulse signal is 7. The low-jitter ultra-wideband pulse signal generator according to claim 3, characterized in that: The frequency division ratio of the M frequency divider is 1, the frequency division ratio of the N frequency divider is 10, and each device in the local oscillator signal path and the intermediate frequency signal path is configured with the goal of low additional time jitter.

8. The low-jitter ultra-wideband pulse signal generator according to claim 1, characterized in that: The local oscillator signal path is cascaded with a low phase noise local oscillator amplifier, so that the local oscillator signal power corresponding to the local oscillator signal path is within a preset device local oscillator rated power range.

9. The low-jitter ultra-wideband pulse signal generator according to claim 1, characterized in that: The output end of the ultra-wideband pulse signal generator is provided with an absorption filter or attenuator, and the absorption filter or attenuator is arranged according to the impedance matching of the ultra-wideband pulse signal generator.

10. A method for generating an ultra-wideband pulse signal, characterized in that: The method is applied to the broadband pulse generator according to any one of claims 1 to 9, and the method comprises: Adjusting device configuration parameters in the local oscillator signal path to change the center frequency of the ultra-wideband pulse signal; The device configuration parameters in the intermediate frequency signal path are adjusted to change the bandwidth of the ultra-wideband pulse signal.

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