A precise timing device suitable for point-to-point tropospheric scatter communications

Abstract

The present invention discloses a precise time calibration device suitable for point-to-point tropospheric scatter communication. The device is implemented based on a tropospheric scatter communication system, uses a common adjustable constant temperature crystal oscillator to replace an expensive rubidium atomic clock, and performs algorithm design in combination with a communication waveform without affecting communication efficiency, detects and processes frame header information in normal communication, does not add additional time calibration information, extracts timing deviation information, obtains time calibration deviation, and obtains high-precision time calibration deviation information after extracting deviation information. The adjustable constant temperature crystal oscillator is used for real-time time calibration through a serial port or other interface, thereby achieving a clock accuracy deviation between two stations at both ends of point-to-point tropospheric scatter communication that is much smaller than the deviation of the common constant temperature crystal oscillator itself, and achieving the effect of the accuracy deviation of the rubidium atomic clock.

Description

Technical Field

[0001] The invention belongs to the field of tropospheric scatter communications, and in particular relates to a precise timing device suitable for point-to-point tropospheric scatter communications. Background Art

[0002] Currently, tropospheric scatter communication systems are required to have the ability to be quickly opened and to ensure long-term stable transmission after opening. Tropospheric scatter communication systems operate on fast-changing random multipath channels and are particularly sensitive to carrier frequency deviation and timing deviation. The existence of frequency deviation and deviation will seriously affect system performance. Therefore, most of the current tropospheric scatter communication equipment uses rubidium atomic clocks as reference clock sources. The short-term stability of rubidium atomic clocks can reach up to 10-12 orders of magnitude, and the accuracy is ±5×10 -11 ,These characteristics can ensure that the clock accuracy deviation of the stations at both ends of the point-to-point tropospheric scatter ,communication system is extremely small (or even negligible), thus ensuring the transmission performance of the tropospheric scatter ,communication system.

[0003] The reference clock architecture based on rubidium atomic clock makes good use of the stability and accuracy of the reference clock source itself, reducing the clock accuracy deviation of the two end stations of the tropospheric scatter communication system. However, this hardware architecture is expensive, and the reference clock source takes a long time to warm up and stabilize. The price of rubidium atomic clock is more than 10 times that of ordinary adjustable constant temperature crystal oscillators, and the warm-up stabilization time at room temperature is more than 5 times that of ordinary adjustable constant temperature crystal oscillators, resulting in obvious defects in cost control and user experience of tropospheric scatter communication equipment.

[0004] The high cost of tropospheric scatter communication equipment limits the large-scale application of tropospheric scatter communication at the battalion and company levels; the long stable opening time greatly restricts some scenarios that require rapid installation and opening, such as air defense and anti-missile, radar confrontation, etc. Therefore, the current reference clock source architecture based on rubidium atomic clocks is difficult to adapt to current needs. Summary of the invention

[0005] In view of this, the present invention provides a precise time calibration device suitable for point-to-point tropospheric scatter communication, which can avoid the problems of high cost and long stabilization time in the background technology, adopts a common adjustable constant temperature crystal oscillator, and designs an algorithm in combination with the communication waveform without affecting the communication efficiency. The adjustable constant temperature crystal oscillator is calibrated in real time through a serial port (which can also be an SPI, I2C or other interface), thereby achieving a clock accuracy deviation between the two end stations of the point-to-point tropospheric scatter communication that is much smaller than the deviation of the common constant temperature crystal oscillator itself, thereby achieving the effect of the accuracy deviation of the rubidium atomic clock.

[0006] The technical solution adopted by the present invention is:

[0007] A precise timing device suitable for point-to-point tropospheric scatter communication, comprising a timing detection module, an adjustable constant temperature crystal oscillator module, a transceiver, a power amplifier, a duplexer, a tropospheric scatter antenna, and a low noise amplifier; wherein:

[0008] The timing detection module is used to generate detection signals and process detection signals containing time deviations. It controls the adjustable constant temperature crystal oscillator module through timing adjustment to achieve accurate timing.

[0009] The adjustable constant temperature crystal oscillator module is used to provide clock reference, generate clock reference I and clock reference II, ensure that the modules involved in frequency conversion at this end station work under the same reference clock, and accept the timing adjustment control of the timing detection module;

[0010] The transceiver is used to up-convert the transmitted intermediate frequency signal to a radio frequency for wireless transmission in the troposcatter channel;

[0011] The power amplifier is used to amplify the transmitted frequency small signal to offset the attenuation of the tropospheric scatter channel;

[0012] The duplexer is used to isolate the receiving and transmitting in the frequency division duplex system and filter out broadband noise;

[0013] The troposcatter antenna is used to radiate the sent detection signal and receive the detection signal from the other end;

[0014] The low noise amplifier is used to amplify the small radio frequency signal.

[0015] Furthermore, the transceiver is a fixed frequency conversion module operating at a specific frequency point, or a frequency hopping conversion module operating at multiple frequency points according to an agreed frequency hopping pattern.

[0016] Furthermore, the timing detection module includes a detection sequence ROM module, a baseband shaping module, a D / A and up-conversion module, an intermediate frequency amplifier, an A / D and bandpass sampling module, an orthogonal down-conversion module, a matched filtering module, and a clock detection control module;

[0017] Among them, the detection sequence rom module is used to store a specific signal sequence, the sequence form is a pseudo code sequence with autocorrelation and cross-correlation characteristics, or a single frequency sequence;

[0018] The baseband shaping module uses square wave, raised cosine and co-frequency overlapping shaping methods to shape the specific signal sequence and then send it to the D / A and up-conversion module;

[0019] The D / A and up-conversion modules serve as the transmission channel for analog intermediate frequency signals, and are used to convert the formed digital signals into analog signals and attach them to the carrier for channel transmission.

[0020] The IF amplifier and A / D and bandpass sampling modules serve as analog IF receiving channels, receiving the signals in the channel and converting them into digital signals for demodulation;

[0021] The orthogonal down-conversion module converts the digital intermediate frequency signal into a baseband signal and sends the baseband signal to the matched filter module;

[0022] The matched filter module performs matched filtering on the baseband signal to obtain a signal carrying a timing deviation, and then sends it to the clock detection control module;

[0023] The clock detection control module is used to perform clock detection processing.

[0024] Further, the clock detection control module includes a timing detection adjustment state machine, a clock deviation statistics module and a clock deviation calculation and control module;

[0025] The timing detection adjustment state machine ensures that the tropospheric scatter communication system maintains normal operation through timing detection, and extracts the timing deviation information from the detection deviation;

[0026] During normal operation, the tropospheric scatter communication system operates at a non-biased position, and when a left deviation or a right deviation is detected, the deviation amount is accumulated in the clock deviation statistics module;

[0027] When the accumulated statistics reach a certain time length, the deviation conversion calculation is performed in the clock deviation calculation and control module.

[0028] Furthermore, the timing detection adjustment state machine and the clock deviation statistics module:

[0029] When working at the non-biased position, the sampling point is at the optimal sampling point, and the deviation is counted as 0;

[0030] When working in the left deviation position, the deviation amount is counted as -1;

[0031] When operating in the right deviation position, the deviation amount is counted as +1.

[0032] The present invention has the following advantages over the background technology:

[0033] 1. The timing detection module adopted in the present invention detects and processes the frame header information in normal communication without adding additional timing information. It obtains the timing deviation by extracting the timing deviation information. After extracting the deviation information, high-precision timing deviation information is obtained, thereby achieving the effect of the precision deviation of the rubidium atomic clock.

[0034] 2. The adjustable constant temperature crystal oscillator module adopted by the present invention adopts a common adjustable constant temperature crystal oscillator to replace the expensive rubidium atomic clock, so as to realize the rapid preheating and stabilization of the tropospheric scatter communication system, and adjust the constant temperature crystal oscillator through the time synchronization detection control to perform high-precision time synchronization with the opposite station.

[0035] 3. When the two end stations of tropospheric scatter communication use ordinary adjustable constant temperature crystal oscillators as reference clock sources, the present invention can make the clock accuracy deviation of the two end stations much smaller than the deviation of the reference clock source itself, thereby achieving the effect of high-precision atomic clock accuracy deviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is an electrical principle block diagram of a precise timing device suitable for point-to-point tropospheric scatter communication in an embodiment of the present invention.

[0037] Figure 2 1 is an electrical schematic diagram of a timing detection module in an embodiment of the present invention.

[0038] Figure 3 1 is an electrical schematic diagram of a clock detection control module in an embodiment of the present invention.

[0039] Figure 4 It is a schematic diagram of the timing detection adjustment state machine and the timing deviation in the clock deviation statistics in the embodiment of the present invention. DETAILED DESCRIPTION

[0040] like Figure 1-3 As shown, a precise timing device suitable for point-to-point tropospheric scatter communication is implemented based on a tropospheric scatter communication system, and includes a timing detection module 1, an adjustable constant temperature crystal oscillator module 2, a transceiver 3, a power amplifier 4, a duplexer 5, a tropospheric scatter antenna 6, and a low noise amplifier 7. Among them, the timing detection module 1 is used to generate a detection signal and process the received detection signal containing a time deviation, and the adjustable constant temperature crystal oscillator module 2 is controlled by the timing adjustment to achieve precise timing; the adjustable constant temperature crystal oscillator module 2 is used to provide a clock reference, generate clock reference 1 and clock reference 2, and ensure that the modules involved in frequency conversion at this end station work under the same reference clock, and at the same time accept the timing adjustment control of the timing detection module; the transceiver 3 is used to up-convert the transmitted intermediate frequency signal to radio frequency, which is suitable for wireless transmission in the tropospheric scatter channel; the power amplifier 4 is used to amplify the transmitted frequency small signal, thereby offsetting the attenuation of the tropospheric scatter channel; the duplexer 5 is used to realize the reception and transmission isolation in the FDD (frequency division duplex) system, and filter out broadband noise; the tropospheric scatter antenna 6 is used to radiate the transmitted detection signal and receive the detection signal of the opposite end; the low noise amplifier 7 is used to amplify the received frequency small signal.

[0041] Transmitting signal channel: the timing detection module 1 generates an intermediate frequency transmission signal, which carries timing deviation information or correction deviation characteristics; the up-conversion module of the transceiver 3 receives the intermediate frequency signal, and converts it into a small transmitting frequency signal through up-conversion; the input end of the power amplifier 4 receives the small transmitting frequency signal, and after amplification by the power amplifier, it outputs a large transmitting frequency signal; the transmitting end of the duplexer 5 receives the large transmitting frequency signal, isolates the influence of the transmitting signal on the receiving end, and outputs it to the tropospheric scattering antenna 6; the tropospheric scattering antenna 6 directionally radiates the radio frequency signal into the wireless space to complete the signal transmission process.

[0042] Receiving signal channel: The tropospheric scatter antenna 6 receives the RF signal from the opposite station in a directionally manner. At this time, the received signal is an extremely weak RF signal; the weak RF signal enters the duplexer 5, filters out broadband noise, and is output to the receiving end of the duplexer; the input end of the low-noise amplifier 5 receives the small RF signal, and after amplification, it is output to the receiving channel of the transceiver 3; the receiving channel of the transceiver 3 outputs an intermediate frequency signal after down-conversion and amplification; the timing detection module 1 receives the intermediate frequency signal, performs timing detection, and realizes high-precision timing.

[0043] The timing detection module 1 includes three parts: sending, receiving, and clock detection control. The sending part includes a detection sequence ROM module 8, a baseband shaping module 9, and a D / A and up-conversion module 10; the receiving part includes an intermediate frequency amplifier 11, an A / D and bandpass sampling module 12, an orthogonal down-conversion module 13, and a matched filter module 14; and the clock detection control module 15 realizes clock deviation detection, calculation, and control. The detection sequence of the sending part needs to have good autocorrelation and cross-correlation characteristics, and can usually use m sequence, M sequence, and gold sequence.

[0044] The clock detection control module 15 includes a timing detection adjustment state machine 16, a clock deviation statistics module 17, and a clock deviation calculation and control module 18; wherein the timing detection adjustment state machine 16 implements timing detection to ensure that the tropospheric scatter communication system maintains normal operation, and extracts timing deviation information from the detection deviation; the clock deviation statistics module 17 performs statistics on the received timing deviation information to ensure timeliness while ensuring the reliability and stability of the adjustment; the clock deviation calculation and control module 18 performs conversion calculations based on the statistical results to adapt to the control format of the reference clock source to achieve timing adjustment.

[0045] The following is another embodiment:

[0046] Reference Figures 1 to 3 A precise timing device suitable for point-to-point tropospheric scatter communication is composed of a timing detection module 1, an adjustable constant temperature crystal oscillator module 2, a transceiver 3, a power amplifier 4, a duplexer 5, a tropospheric scatter antenna 6 and a low noise amplifier 7. Figure 1This is an electrical principle block diagram, and the embodiments are as follows Figure 1 Connect the lines.

[0047] Reference Figure 1 , wherein the timing detection module 1 is used to generate a detection signal and process the detection signal containing a time deviation, and the adjustable constant temperature crystal oscillator module 2 is controlled by the timing adjustment to achieve accurate timing; the adjustable constant temperature crystal oscillator module 2 is used to provide a clock reference, generate a clock reference 1 and a clock reference 2, and ensure that the modules involved in frequency conversion of this terminal station work under the same reference clock, and accept the timing adjustment control of the timing detection module at the same time; the transceiver 3 is used to up-convert the transmitted intermediate frequency signal to a radio frequency, which is suitable for wireless transmission in a tropospheric scatter channel. The implementation form of the transceiver 3 can be a fixed frequency conversion module working at a certain frequency point, or a frequency hopping conversion module that performs frequency hopping at multiple frequency points according to a certain agreed frequency hopping pattern; the power amplifier 4 is used to amplify the small signal of the transmitted frequency, thereby offsetting the attenuation of the tropospheric scatter channel; the duplexer 5 is used to realize the isolation of reception and transmission in the FDD system and filter out broadband noise; the tropospheric scatter antenna 6 is used to radiate the transmitted detection signal and receive the detection signal of the opposite end; the low noise amplifier 7 is used to amplify the small signal of the received frequency.

[0048] Transmitting signal channel: The timing detection module 1 generates a 450MHz intermediate frequency transmitting signal, which carries timing deviation information or correction deviation characteristics. This signal can be in the form of a pseudo code sequence with good cross-correlation and autocorrelation characteristics (such as m sequence, M sequence, gold sequence), or a single frequency signal; the up-conversion module of the transceiver 3 receives the intermediate frequency signal, and converts it into a small transmitting frequency signal through up-conversion. The commonly used radio frequency bands for current tropospheric scatter communications include U / V band, L band, C band, X band, Ku band and Ka band; the input end of the power amplifier 4 receives the small transmitting frequency signal, and after amplification by the power amplifier, it outputs a large transmitting frequency signal; the transmitting end of the duplexer 5 receives the large transmitting frequency signal, isolates the influence of the transmitting signal on the receiving end, and outputs it to the tropospheric scatter antenna 6; the tropospheric scatter antenna 6 radiates the radio frequency signal directionally into the wireless space to complete the signal transmission process.

[0049] Receiving signal channel: The tropospheric scatter antenna 6 receives the RF signal from the opposite station in a directionally manner. At this time, the received signal is an extremely weak RF signal; the weak RF signal enters the duplexer 5, filters out broadband noise, and outputs it to the receiving end of the duplexer; the input end of the low noise amplifier 5 receives the small RF signal and amplifies the small signal. The amplification gain range is generally between 15 and 35 dB, and the amplified signal is output to the receiving channel of the transceiver 3; the receiving channel of the transceiver 3 outputs a 240 MHz intermediate frequency signal after down-conversion amplification; the timing detection module 1 receives the 240 MHz intermediate frequency signal, amplifies the intermediate frequency of the 240 MHz intermediate frequency signal, and performs timing detection. When the signal form of the timing detection part is different, the corresponding signal processing method is used. For example, when the detection sequence is a pseudo code sequence, the autocorrelation processing method is mostly used, or when the detection sequence is a single frequency signal, FFT processing is mostly used, so as to obtain the timing error, extract the timing deviation from the timing error, and control the adjustable constant temperature crystal oscillator module 2 to achieve high-precision timing.

[0050] Figure 2 This is the electrical schematic diagram of the timing detection module 1, refer to Figure 2 It includes three parts: sending, receiving, and clock detection control. The sending part includes a detection sequence ROM8 module, a baseband shaping module 9, a D / A and up-conversion module 10; the receiving part includes an intermediate frequency amplifier 11, an A / D and bandpass sampling module 12, an orthogonal down-conversion module 13, and a matched filter module 14; the clock detection control module 15 realizes clock deviation detection, calculation, and control.

[0051] The detection sequence ROM module 8 stores a specific signal sequence, and the sequence form can be a pseudo code sequence with excellent autocorrelation and cross-correlation characteristics, or a single-frequency sequence; the baseband shaping module 9 makes the transmitted signal conducive to wireless transmission, and can adopt shaping methods such as square wave, raised cosine, and co-frequency overlapping; the D / A and up-conversion module 10 is an analog intermediate frequency signal transmission channel, and the intermediate frequency amplifier 11 and the A / D and bandpass sampling module 12 are analog intermediate frequency receiving channels; the orthogonal down-conversion module 13 converts the digital intermediate frequency signal into a baseband signal, and the baseband signal is sent to the matched filtering module 14. After the matched filtering process, a signal carrying a timing deviation is obtained, and clock detection processing is performed in the clock detection control module 15.

[0052] Figure 3 The electrical schematic diagram of the clock detection control 15 includes a timing detection adjustment state machine 16, a clock deviation statistics module 17, and a clock deviation calculation and control module 18; wherein the timing detection adjustment state machine 16 implements timing detection to ensure that the tropospheric scatter communication system maintains normal operation, and extracts the timing deviation information from the detection deviation. The implementation process is referred to Figure 4During normal operation, the tropospheric scatter communication system operates in a non-biased position. When a left deviation or a right deviation is detected, the deviation is accumulated in the clock deviation statistics module 17. When the accumulated statistics reach a certain time length, the clock deviation calculation and control module 18 performs deviation conversion calculation. The accumulated statistics time length is related to the short stability of the ordinary constant temperature crystal oscillator and the rapid change rate of the tropospheric scatter channel. Under normal circumstances, the statistical time length can generally be set within a few minutes, which can ensure the reliability and stability of the time adjustment, and at the same time does not affect the transmission performance of the tropospheric scatter communication system during the stable convergence process.

[0053] Figure 4 It is a schematic diagram of the timing deviation in the timing detection adjustment state machine 16 and the clock deviation statistics module 17. When there is no clock deviation at the two end stations of the tropospheric scatter communication system, it generally works at the no-bias S0 position. At this time, the sampling point position is at the optimal sampling point, and the deviation amount is counted as 0; when working at the left deviation position, the sampling point is at a maximum sampling phase deviation of Δθ0, and the deviation amount is counted as -1; when working at the right deviation position, the sampling point is at a maximum sampling phase deviation of Δθ1, and the deviation amount is counted as +1.

[0054] In order to facilitate the derivation of the calculation process, some relevant physical quantities in the two end stations of the tropospheric scatter communication system are defined as shown in the table below.

[0055] Serial number Physical meaning symbol 1 Frame rate / Hz Frm 2 Processing clock / MHz F 3 Frame rate increment control word Frm_inc 4 Reference clock source initial stability <![CDATA[A×10 -7 (A is 1 to 5)]]> 5 Reference clock source adjustment accuracy <![CDATA[B×10 -11 (B takes 1 to 2)]]> 6 Timing adjustment at initial stability delta_inc 7 Statistics time length / second T 8 The cumulative value of left deviation within the statistical time length L 9 The cumulative value of right deviation within the statistical time length R

[0056] The calculation process is as follows:

[0057] The frame rate increment control word is represented by a 48-bit binary number, and the frame rate increment control word is:

[0058] <![CDATA[Frm_inc=Frm÷Fs×2 48 ]]> Formula-(1)

[0059] According to the frame rate increment control word, the timing adjustment amount under the initial stability can be obtained as:

[0060] <![CDATA[delta_inc=A×10 -7 ×Frm_inc]]> Formula-(2)

[0061] The number of statistical frames corresponding to the statistical time length is: Frm×T=L+R;

[0062] The cumulative deviation statistic obtained is: (-1×L)+(1×R);

[0063] At this time, the absolute value of the timing deviation of the crystal oscillator of the local station relative to the opposite station is:

[0064] [(-1×L)+(1×R)]÷(Frm×T)÷Frm_inc

[0065] The corresponding adjustment amount of the time error of the constant temperature crystal oscillator of this terminal station relative to the opposite terminal station is:

[0066] [(-1×L)+(1×R)]×delta_inc÷(Frm×T)÷Frm_inc÷(B×10 -11 )

[0067] This control quantity is used to control the constant temperature crystal oscillator of this terminal station, thereby realizing the time synchronization process of this terminal station with the opposite terminal station.

[0068] The calculation example is as follows:

[0069] Serial number Physical meaning symbol Example Value 1 Frame rate / Hz Frm 200Hz 2 Processing clock / MHz F 180MHz 3 Frame rate increment control word Frm_inc 312749974 (rounded) 4 Reference clock source initial stability <![CDATA[A×10 -7 (A is 1 to 5)]]> <![CDATA[2×10 -7 ]]> 5 Reference clock source adjustment accuracy <![CDATA[B×10 -11 (B takes 1 to 2)]]> <![CDATA[1.5×10 -11 ]]> 6 Timing adjustment at initial stability delta_inc 62 (rounded) 7 Statistics time length / second T 180 seconds 8 The cumulative value of left deviation within the statistical time length L 18066 9 The cumulative value of right deviation within the statistical time length R 17934

[0070] At this point, we can calculate:

[0071] The cumulative deviation statistic is: (-1×18066)-(1×17934)=-132;

[0072] The absolute value of the crystal oscillator timing deviation of this end station is:

[0073] -132×62÷(200×180)÷312749974÷1.5×10 -11 =-48.46, which is rounded to -48 in hardware implementation, resulting in a precision deviation of 0.46.

[0074] That is, after 3 minutes of cumulative adjustment, the remaining time error is 0.46×1.5×10 -11 =6.9×10 -12 , achieving the accuracy deviation of the rubidium atomic clock, the original reference clock source, at both end stations of the tropospheric scatter communication system.

[0075] In summary, the present invention is implemented based on a tropospheric scatter communication system, and adopts an ordinary adjustable constant temperature crystal oscillator to replace an expensive rubidium atomic clock. Without affecting the communication efficiency, the algorithm is designed in combination with the communication waveform, and the frame header information in normal communication is detected and processed without adding additional time correction information. The timing deviation is obtained by extracting the timing deviation, and after extracting the deviation information, high-precision time correction deviation information is obtained. The adjustable constant temperature crystal oscillator is calibrated in real time through a serial port (it can also be an SPI, I2C or other interface), thereby achieving a point-to-point tropospheric scatter communication. The clock accuracy deviation between the two end stations is much smaller than the deviation of the ordinary constant temperature crystal oscillator itself, thereby achieving the effect of the rubidium atomic clock accuracy deviation.

Claims

1. A precise timing device suitable for point-to-point tropospheric scatter communication, characterized in that: It includes a timing detection module, an adjustable constant temperature crystal oscillator module, a transceiver, a power amplifier, a duplexer, a tropospheric scatter antenna, and a low noise amplifier; among which: The timing detection module is used to generate detection signals and process detection signals containing time deviations. It controls the adjustable constant temperature crystal oscillator module through timing adjustment to achieve accurate timing. The adjustable constant temperature crystal oscillator module is used to provide clock reference, generate clock reference I and clock reference II, ensure that the modules involved in frequency conversion at this end station work under the same reference clock, and accept the timing adjustment control of the timing detection module; The transceiver is used to up-convert the transmitted intermediate frequency signal to a radio frequency for wireless transmission in the troposcatter channel; The power amplifier is used to amplify the transmitted frequency small signal to offset the attenuation of the tropospheric scatter channel; The duplexer is used to isolate the receiving and transmitting in the frequency division duplex system and filter out broadband noise; The troposcatter antenna is used to radiate the sent detection signal and receive the detection signal from the other end; The low noise amplifier is used to amplify the small received radio frequency signal; The timing detection module includes a detection sequence ROM module, a baseband shaping module, a D / A and up-conversion module, an intermediate frequency amplifier, an A / D and bandpass sampling module, an orthogonal down-conversion module, a matched filtering module, and a clock detection control module; Among them, the detection sequence rom module is used to store a specific signal sequence, the sequence form is a pseudo code sequence with autocorrelation and cross-correlation characteristics, or a single frequency sequence; The baseband shaping module uses square wave, raised cosine and co-frequency overlapping shaping methods to shape the specific signal sequence and then send it to the D / A and up-conversion module; The D / A and up-conversion modules serve as the transmission channel for analog intermediate frequency signals, and are used to convert the formed digital signals into analog signals and attach them to the carrier for channel transmission. The IF amplifier and A / D and bandpass sampling modules serve as analog IF receiving channels, receiving the signals in the channel and converting them into digital signals for demodulation; The orthogonal down-conversion module converts the digital intermediate frequency signal into a baseband signal and sends the baseband signal to the matched filter module; The matched filter module performs matched filtering on the baseband signal to obtain a signal carrying a timing deviation, and then sends it to the clock detection control module; The clock detection control module is used to perform clock detection processing; In the transmission signal channel, the timing detection module generates an intermediate frequency transmission signal, which carries the timing deviation information; the up-conversion module of the transceiver receives the intermediate frequency transmission signal and converts it into a small transmission frequency signal through up-conversion; the input end of the power amplifier receives the small transmission frequency signal, which is amplified by the power amplifier and output as a large transmission frequency signal; the transmitting end of the duplexer receives the large transmission frequency signal, isolates the influence of the transmission signal on the receiving end, and outputs it to the tropospheric scattering antenna; the tropospheric scattering antenna radiates the RF signal directionally into the wireless space to complete the signal transmission process; In the receiving signal channel, the tropospheric scatter antenna directionally receives the RF signal from the opposite station, the RF signal enters the duplexer, filters out broadband noise, and outputs a small RF signal; the low-noise amplifier receives the small RF signal, amplifies it, and outputs it to the receiving channel of the transceiver; the receiving channel of the transceiver is down-converted and amplified, and then outputs an intermediate frequency signal; the timing detection module receives the intermediate frequency signal and performs timing detection to achieve high-precision timing.

2. The precise timing device for point-to-point tropospheric scatter communication according to claim 1, characterized in that: The transceiver is a fixed frequency conversion module operating at a specific frequency point, or a frequency hopping conversion module operating at multiple frequencies according to an agreed frequency hopping pattern.

3. The precise timing device for point-to-point tropospheric scatter communication according to claim 1, characterized in that: The clock detection control module includes a timing detection adjustment state machine, a clock deviation statistics module and a clock deviation calculation and control module; The timing detection adjustment state machine ensures that the tropospheric scatter communication system maintains normal operation through timing detection, and extracts the timing deviation information from the detection deviation; During normal operation, the tropospheric scatter communication system operates at a non-biased position, and when a left deviation or a right deviation is detected, the deviation amount is accumulated in the clock deviation statistics module; When the accumulated statistics reach a certain time length, the deviation conversion calculation is performed in the clock deviation calculation and control module.

4. The precise timing device for point-to-point tropospheric scatter communication according to claim 3, characterized in that: The timing detection adjustment state machine and the clock deviation statistics module: When working at the non-biased position, the sampling point is at the optimal sampling point, and the deviation is counted as 0; When working in the left deviation position, the deviation amount is counted as -1; When operating in the right deviation position, the deviation amount is counted as +1.

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