A compact ultra-high frequency resolution chirped radio frequency source and cold atom gravimeter

Abstract

The utility model relates to cold atom gravimeter technical field especially is a kind of chirp radio frequency source and cold atom gravimeter of small ultrahigh frequency resolution, the utility model's radio frequency output module integrates ultrahigh frequency resolution DDS chip, it is different from the DDS chip of traditional 4FSK function, it has higher frequency control word bit number, can realize hertz level even microhertz level's frequency regulation precision, to meet the stringent requirements of cold atom gravimeter to radio frequency signal frequency resolution, it has the advantages that small, and conducive to the miniaturization integrated, radio frequency output module has the characteristics of ultrahigh frequency resolution is fully competent for the measurement of high-precision cold atom gravimeter, it is convenient for system debugging.

Description

Technical Field

[0001] This utility model relates to the field of cold atom gravimeter technology, and in particular to a small, ultra-high frequency resolution chirped radio frequency source and a cold atom gravimeter. Background Technology

[0002] In the measurement process of a cold atom gravimeter, an radio frequency (RF) source is needed to modulate the laser frequency in a chirped mode to complete Doppler frequency shift compensation and interference fringe measurement control for the continuous resonance between the laser and atoms. During the atomic interference stage, Raman lasers (lasers that directly interact with the atoms) are typically fired three times vertically at the atomic cluster to control the atomic interference. However, during this process, whether the atoms are in free fall or thrown upwards and then falling, their velocities vary at different times due to gravity, resulting in different resonance frequencies with the Raman light under the Doppler effect. Therefore, the Raman light frequency needs to be matched, and to obtain complete interference fringes, an RF source is required to chirp the Raman light frequency. This RF source must be able to synchronize with the main control program; complete the corresponding chirped RF output according to a predetermined timing sequence; achieve a frequency resolution at the μHz level to improve the accuracy of gravity measurement; and be as small as possible to reduce its impact on the system size.

[0003] The radio frequency sources used above are generally divided into two types. One type is generated by editing with instruments similar to arbitrary waveform generators. It is generally composed of a digital signal processor (DSP) or field-programmable gate array (FPGA), a high-speed digital-to-analog converter (DAC), and other radio frequency signal processing units. This solution has sufficient advantages in system debugging and radio frequency performance indicators, but it is large in size and expensive, which is not conducive to system integration and miniaturization.

[0004] Another approach is to use a Direct Digital Synthesizer (DDS) with 4-Frequency Shift Keying (4FSK) functionality to complete the output. This RF source is generally constructed using an FPGA + 4FSK DDS combination with other RF signal processing units. This RF source has advantages such as small size, which is conducive to system integration, reasonable cost, and convenient debugging. However, its frequency resolution is insufficient, it is not universally applicable to high-precision cold atom gravimeters, and its RF phase noise is poor.

[0005] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Utility Model Content

[0006] The technical problem this invention aims to solve is: how to reduce the size of the radio frequency source while increasing its frequency and resolution.

[0007] The present invention adopts the following technical solution: In one aspect, a small, ultra-high frequency resolution chirped radio frequency source is provided, including a control module, a programmable logic module, and a radio frequency output module; wherein, the radio frequency output module integrates an ultra-high frequency resolution DDS chip. The input terminal of the control module is used to receive host data, the first output terminal of the control module is connected to the input terminal of the programmable logic module, and the second output terminal of the control module is connected to the first input terminal of the radio frequency output module to send a frequency configuration signal to the radio frequency output module. The output terminal of the programmable logic module is connected to the second input terminal of the radio frequency output module to send a timing trigger signal to the radio frequency output module; the third input terminal of the radio frequency output module is used to receive a reference clock signal. The radio frequency output module is used to respond to the frequency configuration signal, the timing trigger signal and the external reference clock signal, thereby outputting a radio frequency signal with ultra-high frequency resolution.

[0008] Preferably, the radio frequency output module includes a radio frequency synthesis unit and a radio frequency processing unit; The output terminal of the radio frequency synthesis unit is connected to the input terminal of the radio frequency processing unit; the output terminal of the radio frequency processing unit is used to output radio frequency signals. The first input terminal of the radio frequency synthesis unit is connected to the second output terminal of the control module, the second input terminal of the radio frequency synthesis unit is connected to the output terminal of the programmable logic module, and the third input terminal of the radio frequency synthesis unit is used to receive the reference clock signal. The radio frequency synthesis unit includes an ultra-high frequency resolution DDS chip; the radio frequency processing unit is an LC low-pass filter.

[0009] Preferably, it further includes a communication module, one end of which is used to connect to the communication terminal of the host, and the other end of which is connected to the communication terminal of the control module.

[0010] Preferably, the communication module includes an RS485 communication circuit. One end of the RS485 communication circuit is used to connect to the RS485 communication interface of the host, and the other end of the RS485 communication circuit is connected to the serial port of the control module for transmitting host data sent by the host to the control module.

[0011] Preferably, it also includes a data storage module, which is connected to the control module; The data storage module includes a FLASH chip with a QSPI (Quad Serial Peripheral Interface) interface. The FLASH chip is connected to the control module through the QSPI interface. The FLASH chip is used to store initialization data, and the control module reads the initialization data to drive other modules.

[0012] Preferably, it further includes an edge processing module, wherein the input terminal of the edge processing module is connected to the output terminal of the programmable logic module, and the output terminal of the edge processing module is connected to the radio frequency output module; The edge processing module is used to process the edge of the timing trigger signal and transmit the processed timing trigger signal to the radio frequency output module.

[0013] Preferably, it also includes a power supply module, which is connected to the control module, the programmable logic module and the radio frequency output module respectively, and is used to provide the operating voltage required by the corresponding module.

[0014] Preferably, the power module is used to convert the input voltage to 1.8V, 3.3V, 5V and 12V through DC-DC or LDO (Low-Dropout Regulator) cascading.

[0015] Preferably, the frequency of the radio frequency signal output by the chirped radio frequency source is within 120MHz, and it supports operation under a power supply voltage of 12V~24V, for driving the optical frequency of at least two lasers to perform phase locking.

[0016] In a second aspect, a cold atom gravimeter is provided, comprising a small, ultra-high frequency resolution chirped radio frequency source as described in the first aspect.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model's RF output module integrates an ultra-high frequency resolution DDS chip. Unlike traditional 4FSK DDS chips, it has a higher number of frequency control words, enabling frequency adjustment accuracy at the Hertz or even microhertz level, thus meeting the stringent requirements of cold atom gravimeters for RF signal frequency resolution. The RF output module responds to frequency configuration signals, timing trigger signals, and external reference clock signals to output ultra-high frequency resolution RF signals and achieves Raman light frequency chirp variations to match the resonant frequencies of atoms at different times. It has the advantages of small size and ease of miniaturization and integration. Furthermore, the output RF phase noise is primarily determined by the phase noise of the reference clock signal. The ultra-high frequency resolution of the RF output module makes it fully capable of high-precision cold atom gravimeter measurements and facilitates system debugging. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a small, ultra-high frequency resolution chirped radio frequency source provided in an embodiment of this utility model; Figure 2 This is a schematic diagram of the structure of a radio frequency output module provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a control module provided in an embodiment of the present utility model; Figure 4 This is a schematic diagram of the structure of a programmable logic module provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a radio frequency synthesis unit provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of a radio frequency processing unit provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of an external clock unit provided in an embodiment of the present invention; Figure 8 This is another structural schematic diagram of a small, ultra-high frequency resolution chirped radio frequency source provided in this embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of a communication module provided in an embodiment of this utility model; Figure 10This is a schematic diagram of the structure of a data storage module for a small ultra-high frequency resolution chirped radio frequency source provided in an embodiment of this utility model; Figure 11 This is a schematic diagram of the specific structure of a small ultra-high frequency resolution chirped radio frequency source provided in this embodiment of the utility model; Figure 12 This is a schematic diagram of the structure of a power module provided in an embodiment of the present utility model; Figure 13 This is a timing coordination logic diagram of a small ultra-high frequency resolution chirped radio frequency source provided in an embodiment of this utility model. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0021] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as openly inclusive, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples; that is, although they may be incorporated into embodiments or examples using the above terms for reasons such as order and position, it does not limit them to be incorporated in combination by a single embodiment or example.

[0022] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, for example, the description may use the prefix "A" or "B" to describe the same type of nouns as two independent entities. In this case, the features defined with "A" and "B" are used only to distinguish between similar entities and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0023] In describing some embodiments, the terms "coupled," "coupled," and "connected," and their derivative expressions, may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other. Similarly, the term "coupled" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact. However, the terms "connected" or "coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other, such as "optical coupling" or "wireless connection." The embodiments disclosed herein are not necessarily limited to the scope of this invention.

[0024] Furthermore, the technical features involved in the various embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0025] Example 1: Existing RF sources typically use instruments similar to arbitrary waveform generators for editing and generation. These sources can effectively produce chirped RF outputs for system measurements, offering significant advantages in system debugging and RF performance. However, their large size and high cost hinder system integration and miniaturization. Another approach uses a DDS with 4FSK functionality for output. This type of RF source generally employs an FPGA combined with a 4FSK-enabled DDS and other RF signal processing units. It offers advantages such as small size, ease of system integration, reasonable cost, and convenient debugging. However, its frequency resolution is insufficient, making it unsuitable for high-precision cold atom gravimeters, and its RF phase noise is undesirable.

[0026] To address the problems of the prior art, this embodiment proposes a small, ultra-high frequency resolution chirped radio frequency source. In one embodiment, such as... Figure 1 As shown, the chirped radio frequency source includes a control module, a programmable logic module, and a radio frequency output module. The radio frequency output module integrates an ultra-high frequency resolution DDS chip. The input terminal of the control module is used to receive host data. The first output terminal of the control module is connected to the input terminal of the programmable logic module, and the second output terminal of the control module is connected to the first input terminal of the radio frequency output module to send a frequency configuration signal to the radio frequency output module. The output terminal of the programmable logic module is connected to the second input terminal of the radio frequency output module to send a timing trigger signal to the radio frequency output module. The third input terminal of the radio frequency output module is used to receive a reference clock signal. The radio frequency output module responds to the frequency configuration signal, the timing trigger signal, and the external reference clock signal to output an ultra-high frequency resolution radio frequency signal.

[0027] In one embodiment, the control module is used to receive and parse host data, send a timing coordination signal to the programmable logic module, and send a frequency configuration signal to the radio frequency output module; the programmable logic module is used to generate a timing trigger signal based on the timing coordination signal and transmit the timing trigger signal to the radio frequency output module; the radio frequency output module is used to respond to the frequency configuration signal, the timing trigger signal, and an external reference clock signal, thereby outputting an ultra-high frequency resolution radio frequency signal and realizing the chirp variation of the Raman light frequency to match the resonance frequency of the atom at different times.

[0028] The core function of the control module is to establish a communication link with the external host and to parse and distribute instructions. First, the control module receives host data from the host, which typically includes key indicators of the chirped radio frequency (RF) signal, such as start frequency, stop frequency, chirp slope, signal duration, and output power. Second, the control module parses the received host data, converting it into two types of control signals that can be recognized by downstream modules. One type is a timing coordination signal sent to the programmable logic module (PLM) to unify the timing of each module's operation and ensure the synchronization of the signal generation process. The other type is a frequency configuration signal sent to the RF output module, which contains the frequency control parameters required by the RF output module, providing the basis for generating ultra-high frequency resolution signals.

[0029] In one embodiment, the control module is typically implemented as an embedded microprocessor or microcontroller, featuring miniaturization and low power consumption, meeting the requirements of system integration miniaturization, and differing from the large control architecture of traditional arbitrary waveform generators. In one embodiment, the control module is a microcontroller unit (MCU) minimum system circuit, including a crystal oscillator, a reset circuit, and an MCU chip.

[0030] The programmable logic module (PLC) primarily handles timing synchronization and trigger signal generation, and its hardware platform is typically an FPGA. After receiving the timing coordination signal from the control module, the PLC generates a high-precision timing trigger signal based on a preset logic algorithm. The core function of this timing trigger signal is to provide a precise timing reference for the RF output module, such as controlling the signal generation start time, the timing of the chirp process, and the start / stop switching of signal output. Due to the parallel processing and high-speed logic operation capabilities of the FPGA, the generated timing trigger signal possesses nanosecond-level or even higher timing accuracy, meeting the stringent timing synchronization requirements of high-precision applications such as cold atom gravimeters, and solving the phase noise degradation problem caused by insufficient timing control accuracy in traditional 4FSK-function DDS solutions. In one embodiment, the PLC also receives three signals: an external reference clock input, a chirp count trigger input, and a chirp count reset input, which, together with the timing coordination signal from the control module, generate the output timing trigger signal.

[0031] The core function of the RF output module is to respond to multi-source input signals and generate chirped RF signals with ultra-high frequency resolution. The input signals of the RF output module include three types: first, the frequency configuration signal issued by the control module, providing the basic configuration for the signal frequency; second, the timing trigger signal issued by the programmable logic module, providing precise timing drive for signal generation; and third, the externally input reference clock signal, which is typically a highly stable atomic clock or temperature-controlled crystal oscillator output signal, providing core assurance for the frequency stability and resolution of the RF signal.

[0032] In one embodiment, the RF output module typically integrates components such as an ultra-high frequency resolution DDS (direct digital frequency synthesizer) chip, an RF amplification unit, and a filtering unit. Among these, the ultra-high frequency resolution DDS is key to achieving ultra-high frequency resolution. It performs fine-tuning of the frequency through frequency configuration signals issued by the control module, and combined with precise driving by timing trigger signals, it can generate chirped signals with continuously changing frequencies.

[0033] Ultimately, the chirped radio frequency signal output by the radio frequency output module can achieve dynamic chirped changes in the Raman light frequency. Its core purpose is to match the resonant frequency of atoms in the cold atom gravimeter at different times. During the free fall of cold atoms, the resonant frequency of the atoms will change slightly with the change of the gravitational field. The dynamic frequency change characteristics of the chirped radio frequency signal can track the change of the resonant frequency in real time, thereby achieving precise control of the atomic state.

[0034] In one embodiment, the frequency of the radio frequency signal output by the chirped radio frequency source is within 120MHz and supports operation under a supply voltage of 12V~24V, used to drive the optical frequencies of at least two lasers for phase locking. With the chirped radio frequency output, the radio frequency requirements for chirped changes in Raman light frequency in a cold atom gravimeter can be met.

[0035] In summary, the miniaturized, ultra-high frequency resolution chirped RF source adopts a miniaturized modular architecture consisting of a control module, a programmable logic module, and an RF output module, which solves the problems of large size and high cost of traditional arbitrary waveform generators. Each module can be embedded or board-level designed, making it easy to integrate into miniaturized systems while significantly reducing hardware costs.

[0036] By integrating an ultra-high frequency resolution DDS chip and combining it with the fine frequency configuration of the control module, ultra-high frequency resolution is achieved to meet the high-precision application requirements of cold atom gravimeters. High-precision timing trigger signals generated by programmable logic modules are used to unify the working timing of each module and reduce phase noise caused by timing asynchrony. An external high-stability reference clock is introduced to further improve the frequency stability of the RF signal and improve the phase noise performance, thereby solving the problems of insufficient frequency resolution and poor phase noise in traditional 4FSK function DDS solutions.

[0037] In one embodiment, such as Figure 2 As shown, the RF output module includes an RF synthesis unit and an RF processing unit; the output terminal of the RF synthesis unit is connected to the input terminal of the RF processing unit; the output terminal of the RF processing unit is used to output RF signals; the first input terminal of the RF synthesis unit is connected to the second output terminal of the control module, the second input terminal of the RF synthesis unit is connected to the output terminal of the programmable logic module, and the third input terminal of the RF synthesis unit is used to receive the reference clock signal.

[0038] The core function of the radio frequency synthesis unit is to respond to the frequency configuration signal from the control module, the timing trigger signal from the programmable logic module, and the external reference clock signal, and output a radio frequency signal with ultra-high frequency resolution. In one embodiment, the hardware carrier of the radio frequency synthesis unit is typically an ultra-high frequency resolution direct digital frequency synthesis chip. Unlike traditional 4FSK DDS chips, it has a higher number of frequency control words and can achieve frequency adjustment accuracy at the Hertz or even microhertz level, thereby meeting the stringent requirements of cold atom gravimeters for radio frequency signal resolution.

[0039] During operation, the RF synthesis unit first receives a high-stability reference clock signal from an external input. Next, it receives a frequency configuration signal from the control module. This signal contains key parameters such as the start frequency, end frequency, and chirp slope of the chirped RF signal. The RF synthesis unit can adjust its internal frequency control in real time according to the frequency configuration signal to achieve dynamic and continuous changes in the RF signal frequency, i.e., the chirp characteristic. Finally, it receives a timing trigger signal from the programmable logic module. This signal controls the start and stop times and timing cycle of the RF synthesis unit's signal generation, ensuring that the signal generation process is synchronized with the overall timing of the RF source, thus avoiding the introduction of additional phase noise due to timing deviations.

[0040] The working mechanism of the radio frequency processing unit is mainly reflected in two aspects: first, filtering out high-frequency spurious components in the output signal of the radio frequency synthesis unit; and second, suppressing harmonic distortion of the signal and reducing interference of non-target frequency components on system measurements, thereby improving key radio frequency indicators such as phase noise and spurious suppression of the output radio frequency signal.

[0041] In one embodiment, such as Figure 3 , Figure 4 , Figure 5 and Figure 6 The diagrams shown are schematic representations of the control module, the programmable logic module (partial pin diagram), the radio frequency synthesis unit, and the radio frequency processing unit, respectively.

[0042] The control module is an STM32H750VBT6, the programmable logic module is an EP4CE15E22C8N, the radio frequency synthesis unit includes an ultra-high frequency resolution DDS chip, the ultra-high frequency resolution DDS chip is an AD9854ASVZ, and the radio frequency processing unit is an LC low-pass filter.

[0043] The 485 pins on the control module (corresponding to the input terminals of the control module, such as 485_TX2 and 485_RX2, etc.) are used to receive host data.

[0044] The FMC_ pins on the control module (each corresponding to the first output terminal of the control module, such as FMC_nWE, etc.) are respectively connected to the corresponding pins on the programmable logic module.

[0045] The 9854_ pin on the control module (corresponding to the second output terminal of the control module, such as 9854_D1_MCU) and the 9854_ pin on the programmable logic module (corresponding to the second output terminal of the control module, such as 9854_D1_FPGA) are respectively connected to the 9854_ pin on the radio frequency synthesis unit (corresponding to the first input terminal and the second input terminal of the radio frequency synthesis unit, such as 9854_D1).

[0046] The REFCLK pin on the RF synthesis unit (corresponding to the third input of the RF synthesis unit) is used to receive an external clock unit (such as...). Figure 7 The reference clock signal emitted (as shown).

[0047] The IOUT1- and IOUT1+ pins (corresponding to the output terminals of the RF synthesis unit) on the RF synthesis unit are connected to the input terminals (IOUT1- and IOUT1+) of the RF processing unit, respectively. The input terminal of the RF processing unit is a DOSIN-806-0261 connector, which is used to output the final RF signal.

[0048] It is worth noting that other external circuits for each circuit structure are not described in detail in this embodiment. The above figures and corresponding descriptions only illustrate the important pin connections. The connection methods of other pins can be specifically designed by referring to the chip manual of the corresponding structure, and will not be described in detail in this embodiment.

[0049] In summary, the design of the RF output module not only solves the problem of insufficient frequency resolution in the traditional 4FSK-DDS scheme by using an ultra-high frequency resolution RF synthesis unit, but also improves RF performance while taking into account the requirements of system miniaturization and low power consumption through the passive filtering design of the LC low-pass filter.

[0050] To enable communication between the host and the control module, in one embodiment, such as Figure 8 As shown, the small ultra-high frequency resolution chirped radio frequency source also includes a communication module. One end of the communication module is used to connect to the communication terminal of the host, and the other end of the communication module is connected to the communication terminal of the control module.

[0051] In one embodiment, such as Figure 9 As shown, the communication module includes an RS485 communication circuit. One end of the RS485 communication circuit is used to connect to the RS485 communication interface of the host, and the other end of the RS485 communication circuit is connected to the serial port of the control module to transmit host data sent by the host to the control module.

[0052] The 485_ pins on the communication module are connected to the corresponding 485_ pins on the control module (for example, the 485_RX2 pin on the communication module is connected to the 485_RX2 pin on the control module). The RS485_2N and RS485_2P pins on the control module are connected to the host.

[0053] The RS485 communication circuit is mainly used to convert the highly interference-resistant host data sent by the host into a data level that the MCU can process, and then send it to the control module.

[0054] In one embodiment, such as Figure 10 As shown, the small ultra-high frequency resolution chirped radio frequency source also includes a data storage module, which is connected to the control module. The data storage module includes a FLASH chip with a QSPI interface. The FLASH chip is connected to the control module through the QSPI interface. The FLASH chip is used to store initialization data, and the control module reads the initialization data to drive other modules.

[0055] The data storage module uses a FLASH chip with a QSPI interface. QSPI, or four-wire serial peripheral interface, has a higher data read and write speed, which can meet the control module's need to quickly read initialization data during system startup and shorten system startup time. At the same time, the FLASH chip has non-volatile storage characteristics, which can retain the stored data without loss after the system loses power. This eliminates the need for the external host to resend initialization parameters every time the system is powered on, greatly improving the ease of use and independence of the system.

[0056] The core function of the data storage module is to store the initialization data required by each module in the radio frequency source during operation. This initialization data includes the hardware configuration parameters of each module, such as the timing reference parameters of the programmable logic module, the initial frequency calibration parameters of the radio frequency synthesis unit, and the filter configuration parameters of the radio frequency processing unit. More specific details will not be elaborated in this embodiment.

[0057] The timing trigger signals generated by programmable logic modules such as FPGAs may suffer from insufficient rising / falling edge slopes, edge jitter, or glitches in high-frequency operating scenarios. These defects can cause deviations in the timing reference of the trigger signals received by the RF output module, thereby affecting the frequency switching synchronization of the RF synthesis unit and ultimately degrading the phase noise and frequency resolution of the output RF signal. To address these issues, in one embodiment, such as... Figure 11 As shown, the small ultra-high frequency resolution chirped radio source also includes an edge processing module. The input terminal of the edge processing module is connected to the output terminal of the programmable logic module, and the output terminal of the edge processing module is connected to the radio frequency output module. The edge processing module is used to process the timing trigger signal and transmit the processed timing trigger signal to the radio frequency output module.

[0058] The edge processing module includes an ultrafast edge processing chip and its supporting circuitry. In one embodiment, the ultrafast edge processing chip possesses steep edge shaping capabilities, which can boost the rising / falling edge slope of the original timing trigger signal to the nanosecond or even picosecond level, eliminating the slow transition process of the signal edge; it also possesses low-jitter signal transmission characteristics, capable of filtering out glitches and random timing jitter in the original signal, and outputting a phase-stable trigger signal. The optimized high-precision timing trigger signal is transmitted to the RF output module through a supporting buffer circuit, providing a precise timing drive reference for the RF synthesis unit.

[0059] In order to power the various modules, in one embodiment, such as Figure 12 As shown, the small, ultra-high frequency resolution chirped radio frequency source also includes a power supply module. The power supply module is connected to the control module, the programmable logic module, and the radio frequency output module, respectively, and is used to provide the operating voltage required by the corresponding modules. Specifically, the power supply module is used to convert the input voltage to 1.8V, 3.3V, 5V, and 12V via a DC-DC converter or an LDO cascaded configuration.

[0060] In one embodiment, the power module is also connected to all other modules. The power module mainly supplies power to each module through DC-DC converters, LDO cascades, etc. For critical modules, it provides high-quality, low-noise power to improve the phase noise of radio frequency signals.

[0061] To address the heat dissipation issues of the power module and various chips, in one embodiment, the chirped RF source further includes a heat dissipation module (not shown in the figure). The heat dissipation module comprises a heat dissipation structure and its decoupled power supply circuit. The heat dissipation module is primarily used to address the heat generated by the power module and RF output module, thereby improving system stability.

[0062] In one embodiment, such as Figure 13 The diagram illustrates the timing coordination logic of a small, ultra-high frequency resolution chirped radio frequency source. Using the timing trigger signal output by the programmable logic module (“FSK trigger” in the diagram) as the periodic reference, within different FSK times (T0-T3), the control module sends frequency configuration signals (corresponding to chirped frequencies Fc00-Fc03 in the diagram) to the radio frequency output module via a write frequency trigger, thus switching the FSK frequency (F0 / F1). Simultaneously, chirped count triggering and chirped reset triggering assist in timing coordination, thereby cyclically completing the dynamic chirped frequency change of the radio frequency output module to match the atomic resonance frequency. It is worth noting that the descriptions of the methods in this embodiment are all prior art and will not be elaborated upon further in this embodiment.

[0063] In summary, this embodiment receives and parses host data through the control module, sends timing coordination signals to the programmable logic module, and sends frequency configuration signals to the RF output module. The programmable logic module generates timing trigger signals based on the timing coordination signals and transmits them to the RF output module. The RF output module responds to the frequency configuration signals, timing trigger signals, and external reference clock signals, thereby outputting an ultra-high frequency resolution RF signal and realizing the chirp variation of Raman light frequency to match the resonance frequency of atoms at different times. It has the advantages of small size and easy miniaturization integration. At the same time, the output RF phase noise is basically determined by the phase noise of the reference clock signal. The RF output module has the characteristics of ultra-high frequency resolution and is fully capable of high-precision cold atom gravimeter measurements, which facilitates system debugging.

[0064] Example 2: To provide a detailed description of the small, ultra-high frequency resolution chirped RF source described in Example 1, in one embodiment, the control module includes a crystal oscillator, a reset circuit, and an MCU chip; the communication module includes a 485 chip, an ESD (Electro-Static Discharge) protection circuit, and a communication terminal matching resistor; the data storage module includes a QSPI interface FLASH chip; the programmable logic module includes a clock circuit, a reset circuit, and an FPGA chip; the edge processing module includes an ultra-fast edge processing chip and its supporting circuitry; the RF synthesis unit includes an AD9854 (frequency resolution approximately 1µHz), a multi-channel RF transformer, a reference clock input interface circuit, and a quadrature RF output maintenance interface; the RF processing unit is a 7th-order LC low-pass filter; the power supply module mainly includes a switching power supply chip, a protection circuit, and a multi-stage low-noise LDO chip; and the heat dissipation module includes a heat dissipation structure and its decoupled power supply circuit.

[0065] The specific structure of each module and its overall operation are not explained in detail in this embodiment.

[0066] Example 3: This embodiment proposes a cold atom gravimeter, including a small, ultra-high frequency resolution chirped radio frequency source as described in Embodiment 1.

[0067] This embodiment receives and parses host data through the control module, sends timing coordination signals to the programmable logic module, and sends frequency configuration signals to the RF output module. The programmable logic module generates timing trigger signals based on the timing coordination signals and transmits them to the RF output module. The RF output module responds to the frequency configuration signals, timing trigger signals, and external reference clock signals, thereby outputting ultra-high frequency resolution RF signals and realizing the chirp variation of Raman light frequencies to match the resonance frequencies of atoms at different times. It has the advantages of small size and easy miniaturization integration. At the same time, the output RF phase noise is basically determined by the phase noise of the reference clock signal. The RF output module has ultra-high frequency resolution characteristics and is fully capable of high-precision cold atom gravimeter measurements, which facilitates system debugging.

[0068] For the specific structure of the small ultra-high frequency resolution chirped radio frequency source, please refer to Embodiment 1, which will not be repeated in this embodiment.

[0069] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A small, ultra-high frequency resolution chirped radio frequency source, characterized in that, It includes a control module, a programmable logic module, and an RF output module; the RF output module integrates an ultra-high frequency resolution DDS chip. The input terminal of the control module is used to receive host data, the first output terminal of the control module is connected to the input terminal of the programmable logic module, and the second output terminal of the control module is connected to the first input terminal of the radio frequency output module to send a frequency configuration signal to the radio frequency output module. The output terminal of the programmable logic module is connected to the second input terminal of the radio frequency output module to send a timing trigger signal to the radio frequency output module; the third input terminal of the radio frequency output module is used to receive a reference clock signal. The radio frequency output module is used to respond to the frequency configuration signal, the timing trigger signal and the external reference clock signal, thereby outputting a radio frequency signal with ultra-high frequency resolution.

2. The small, ultra-high frequency resolution chirped radio frequency source according to claim 1, characterized in that, The radio frequency output module includes a radio frequency synthesis unit and a radio frequency processing unit; The output terminal of the radio frequency synthesis unit is connected to the input terminal of the radio frequency processing unit; the output terminal of the radio frequency processing unit is used to output radio frequency signals. The first input terminal of the radio frequency synthesis unit is connected to the second output terminal of the control module, the second input terminal of the radio frequency synthesis unit is connected to the output terminal of the programmable logic module, and the third input terminal of the radio frequency synthesis unit is used to receive the reference clock signal. The radio frequency synthesis unit includes an ultra-high frequency resolution DDS chip; the radio frequency processing unit is an LC low-pass filter.

3. The small, ultra-high frequency resolution chirped radio frequency source according to claim 1, characterized in that, It also includes a communication module, one end of which is used to connect to the communication terminal of the host, and the other end of which is connected to the communication terminal of the control module.

4. The small, ultra-high frequency resolution chirped radio frequency source according to claim 3, characterized in that, The communication module includes an RS485 communication circuit. One end of the RS485 communication circuit is used to connect to the RS485 communication interface of the host, and the other end of the RS485 communication circuit is connected to the serial port of the control module to transmit host data sent by the host to the control module.

5. The small, ultra-high frequency resolution chirped radio frequency source according to claim 1, characterized in that, It also includes a data storage module, which is connected to the control module; The data storage module includes a FLASH chip with a QSPI interface. The FLASH chip is connected to the control module via the QSPI interface. The FLASH chip is used to store initialization data, and the control module reads the initialization data to drive the programmable logic module and the radio frequency output module.

6. The small, ultra-high frequency resolution chirped radio frequency source according to claim 1, characterized in that, It also includes an edge processing module, the input of which is connected to the output of the programmable logic module, and the output of which is connected to the radio frequency output module; The edge processing module is used to process the edge of the timing trigger signal and transmit the processed timing trigger signal to the radio frequency output module.

7. The small, ultra-high frequency resolution chirped radio frequency source according to claim 1, characterized in that, It also includes a power supply module, which is connected to the control module, the programmable logic module and the radio frequency output module respectively, and is used to provide the operating voltage required by the corresponding module.

8. The small, ultra-high frequency resolution chirped radio frequency source according to claim 7, characterized in that, The power module is used to convert the input voltage to 1.8V, 3.3V, 5V and 12V through DC-DC or LDO cascade.

9. The small, ultra-high frequency resolution chirped radio frequency source according to claim 1, characterized in that, The frequency of the radio frequency signal output by the chirped radio frequency source is within 120MHz and supports operation under a power supply voltage of 12V~24V, and is used to drive the optical frequency of at least two lasers for phase locking.

10. A cold atom gravimeter, characterized in that, Including the small, ultra-high frequency resolution chirped radio frequency source as described in any one of claims 1-9.

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