A method and apparatus for digital filtering of time pulses

Abstract

The application discloses a kind of digital filtering method and device of time pulse, belong to signal processing field, it is characterized in that: original time pulse signal is carried out signal quality evaluation;Original time pulse signal enters filter and is filtered;Filter adjusts filtering parameter according to the signal quality evaluation result;According to the phase of time pulse output by filter, digital phase-locked loop is carried out simultaneously, and phase compensation is carried out, to obtain local time pulse.By carrying out signal quality evaluation, the filtering method and device of the application have fault prediction ability, and improve equipment interference ability, and the problem of long maintenance period after single time source failure.The filtering method of the application can adjust filtering operating parameter according to the quality of external signal to adapt to different environmental noise to obtain optimal filtering operating parameter.At the same time, by real-time detection transmission path delay, phase compensation can be dynamically adjusted, so as to realize providing higher precision time service.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of signal processing, and particularly relates to a method and device for digital filtering of a time pulse. BACKGROUND

[0002] In time synchronization applications, a high-speed and reliable filtering scheme is needed to restore the time pulse. The current digital filtering methods for the time pulse generally include delay de-bouncing filtering, sliding window filtering and multiple sampling voting. These traditional schemes generally have the following defects: 1. In the case of strong interference, in order to prevent false triggering, a large time constant filter or an increased voting number method is used, resulting in large signal delay. Even if phase compensation technology is used later, the phase of the filtered signal output signal will still jitter due to the uncertainty of the interference signal; 2. There is no signal quality assessment, and the device operating state cannot be predicted. SUMMARY

[0003] The present application aims to solve the above problems, and provides a digital filtering method and device for a time pulse with high-speed phase response and device fault prediction function.

[0004] The digital filtering method for the time pulse according to the present application includes signal quality assessment of the original time pulse signal. Through signal quality assessment analysis, the filtering parameters of the filter can be adjusted to cope with signal interference, and according to the signal quality, it can be inferred whether there is a fault hidden danger in the time device, prompting the staff to carry out necessary maintenance.

[0005] The original time pulse signal enters the filter for filtering; the filter adjusts the filtering parameters according to the aforementioned signal quality assessment result; the filter adjusts the inversion threshold of 0 and 1 output according to the aforementioned signal quality assessment result, as well as the filter flip lock and unlock time slice parameters; using the signal quality analysis result, the filter flip threshold and filter time constant can be preset, so that the phase response speed can be improved; at the same time, the filter flip lock time slice and unlock time slice can be preset, so that the strong interference false triggering condition can be eliminated.

[0006] The phase of the time pulse output by the filter is digitally phase-locked, and phase compensation is performed to obtain a local synchronous time pulse.

[0007] Further, the method for digital filtering of time pulses according to the present application, the signal quality assessment of the original time pulse signal comprises: counting the number of interference and pulse width of the original time pulse signal; counting the phase jitter of the original time pulse signal, and performing fault prediction. In the technical solution, the fault includes two kinds of external signal link fault and local device fault, and whether the external fault or the internal fault depends on whether a signal diagnosis circuit is added, and the diagnosis circuit is divided into a system-level diagnosis circuit and a local diagnosis circuit, the system-level diagnosis circuit can diagnose the link fault position (such as cable fault, signal source fault, and local device fault), and the local diagnosis circuit can diagnose whether it is an internal device fault or an external device fault.

[0008] Further, the method for digital filtering of time pulses according to the present application, the adjustment of the filtering parameters comprises adjustment of the filter sliding window size and the sampling rate.

[0009] The filter sliding window size is greater than 2 times the ratio of the maximum interference pulse width to the sampling rate.

[0010] If the above conditions cannot be met under the default sampling rate, the sampling rate can be dynamically reduced to adapt to the requirement of the sliding window size.

[0011] Further, the method for digital filtering of time pulses according to the present application, the threshold value is equal to the sliding window size × K1 × signal quality; and the value range of K1 × signal quality is 0.5-1. Wherein, K1 is a system parameter which needs to be adjusted to a suitable value according to specific device test, similar to the PID adjustment parameter.

[0012] Further, the method for digital filtering of time pulses according to the present application, the equivalent phase difference of the phase compensation is equal to K2 × phase difference; and the value range of the phase difference is -180°-+180°. Wherein, K2 is a system parameter which needs to be adjusted to a suitable value according to specific device parameters, and the parameter is proportional to the clock frequency of the system, similar to the PID adjustment parameter.

[0013] The device for digital filtering of time pulses according to the present application comprises a signal quality analysis unit, a filter unit, and a phase-locked loop / phase synchronization unit.

[0014] The signal quality analysis unit, the filter unit, and the phase-locked loop / phase synchronization unit are electrically connected in sequence.

[0015] The signal quality analysis unit and the phase-locked loop / phase synchronization unit are electrically connected.

[0016] The signal quality analysis unit is used for signal quality evaluation on the original time pulse signal; through signal quality evaluation analysis, the filter parameter can be adjusted to cope with signal interference, and according to the signal quality, it can be inferred whether the time synchronization equipment has hidden troubles, prompting the staff to carry out necessary maintenance.

[0017] The filter unit is used for the original time pulse signal to enter the filter for filtering; the filter adjusts the filter parameter according to the signal quality evaluation result; the filter adjusts the inversion threshold of 0 and 1 according to the signal quality evaluation result; the filter flip lock and unlock time slice adjustment; by using the signal quality analysis result, the filter flip threshold and the filter time constant can be preset, so that the phase response speed can be improved; at the same time, the filter flip lock time slice and the unlock time slice can be preset, so that the strong interference false triggering condition can be eliminated.

[0018] The phase-locked loop / phase synchronization unit is used for digital phase-locked loop according to the phase of the time pulse output by the filter, and phase compensation is carried out to obtain the local time pulse.

[0019] Further, the signal quality analysis unit of the time pulse digital filtering device is used for signal quality evaluation on the original time pulse signal, including the interference times and pulse width of the original time pulse signal are counted; the phase jitter of the original time pulse signal is counted; and fault prediction is carried out.

[0020] Further, the filter in the filter unit adjusts the filter parameter according to the signal quality evaluation result, including the adjustment of the filter sliding window size and the sampling rate; the filter sliding window size is greater than 2 times the ratio of the maximum interference pulse width and the sampling rate; if the above conditions cannot be met under the default sampling rate, the sampling rate can be dynamically reduced to adapt to the requirement of the sliding window size.

[0021] Further, the threshold value is equal to the sliding window size* K1* signal quality; the value range of K1* signal quality is 0.5~1.

[0022] Further, the phase-locked loop / phase synchronization unit includes a phase discriminator, a phase compensator, a loop filter, a voltage-controlled oscillator and a frequency divider; the inputs of the phase discriminator and the phase compensator are connected with the loop filter; the loop filter, the voltage-controlled oscillator and the frequency divider are connected in sequence; the output end of the frequency divider is connected with the input end of the phase discriminator.

[0023] The digital filtering method and apparatus for time pulses described in this invention, through signal quality assessment, endow the filtering method and apparatus with fault prediction capabilities, while simultaneously improving equipment interference resistance and addressing the issue of long maintenance cycles after a single time source failure. The filtering method of this invention can adjust filtering operating parameters according to the quality of external signals to adapt to different environmental noise levels, thereby obtaining optimal filtering operating parameters. Furthermore, by dynamically adjusting phase compensation through real-time detection of transmission path delay, higher accuracy time synchronization can be achieved. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the time slice principle according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the digital filtering device for time pulses according to an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram illustrating the phase compensation principle described in an embodiment of the present invention. Detailed Implementation

[0027] The digital filtering method and apparatus for time synchronization pulses of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0028] Example 1

[0029] This embodiment discloses a digital filtering method for time synchronization pulses, including signal quality assessment of the original time synchronization pulse signal; the filtering parameters of the filter can be adjusted to deal with signal interference through signal quality assessment and analysis, and the presence of potential faults in the time synchronization equipment can be inferred based on the signal quality, prompting staff to carry out necessary maintenance.

[0030] The original time-synchronized pulse signal enters the filter for filtering; the filter adjusts its filtering parameters based on the aforementioned signal quality assessment results; the filter adjusts the inversion thresholds for output 0 and 1 based on the aforementioned signal quality assessment results; the filter's flip-lock and unlock time slices are adjusted; in this embodiment, the worse the signal quality, the larger the flip threshold, and the more difficult the state flip; a larger threshold means the filter can filter out more signal glitches; in this embodiment, the filter time constant adjustment principle is: the worse the signal quality, the larger the time constant; the time constant is the signal sampling interval time; a longer sampling interval means the filter can filter out a wider range of interference pulses. By using the signal quality analysis results, the filter's flip threshold and filter time constant are preset, thereby improving the phase response speed; simultaneously, as Figure 1 As shown, the preset filter flips the lock and unlock time slices, which can prevent false triggering due to strong interference.

[0031] The phase of the time pulse output by the filter is digitally phase-locked, and phase compensation is simultaneously performed; specifically, a phase detector first calculates the phase difference between the local pulse and the filter output signal, then a system compensation phase is inserted (simple addition operation), the compensated data enters the loop filter for operation, then a voltage-controlled oscillator is controlled to obtain a high-precision clock pulse, and then a frequency divider is used to divide the frequency to obtain the local synchronous time pulse. The phase compensation link can be added before or after the loop filter.

[0032] The digital filtering method for the time pulse according to the embodiments of the present disclosure, the signal quality evaluation of the original time pulse signal includes counting the number of disturbances and the pulse width of the original time pulse signal; counting the phase jitter of the original time pulse signal; and performing fault prediction to speculate whether the time synchronization device has hidden faults, prompting the staff to perform necessary maintenance.

[0033] The digital filtering method for the time pulse according to the embodiments of the present disclosure, the adjustment of the filter parameters includes adjustment of the filter sliding window size and the sampling rate; the filter sliding window size is greater than 2 times the ratio of the maximum disturbance pulse width to the sampling rate; if the above conditions cannot be met under the default sampling rate, the sampling rate can be dynamically reduced to meet the requirements of the sliding window size.

[0034] The sliding window size is determined according to the specific situation of the use of device resources. For example, the maximum length of the system sliding window is 1024. In theory, the larger the window, the better, but in specific applications, the sliding window size is generally taken as 10-1024 based on cost considerations. According to the Nyquist theorem, the minimum value of the sliding window is as follows:

[0035] The minimum value of the sliding window = (maximum disturbance pulse width / system sampling interval time) x 2.

[0036] If the minimum value of the sliding window is greater than the maximum window length of the system, the system sampling interval time needs to be lengthened to meet the above formula. When the maximum system sampling interval time calculated still cannot meet the above formula, the system needs to output a fault signal to prompt the system parameter adjustment failure.

[0037] In the embodiments of the present disclosure, the threshold value is equal to the sliding window size x K1 x signal quality; the value of K1 x signal quality ranges from 0.5 to 1. For example, in the case of greater interference, the value is 0.8 (in actual application, the value varies according to the quality of the input signal, the accuracy requirement of the system, and the reliability requirement, such as 0.7 for civilian high-precision and 0.8 for high-risk high-reliability), and the sliding window is 1000, so the threshold value is 800, that is, only when 80% of the sampling values are the same, the input signal is used for output, otherwise the output remains unchanged.

[0038] In practical applications, K1 is a system parameter that needs to be adjusted to a suitable value according to specific device testing, similar to PID adjustment parameters. For example: the real signal is at a low level, and 20% of the interference spikes (which can be a wide pulse interference or a combination of multiple narrow pulses) are coupled. According to the above conditions, it can be deduced that within a sampling window, 20% of the time is interfered with sampling to 1. In order to eliminate this 20% interference, the filter is set as follows: threshold = (50% + 20%) x sliding window size; wherein 50% is the minimum trigger threshold, K1 = 1, and 20% is the signal quality. From a statistical point of view, the value of the real signal reflected by 70% of the signals in the sampling window is 1, so the value of 70% is 1. If the value of 0 and 1 does not exceed 70%, the status quo is maintained.

[0039] K1 does not have a fixed precise value, which is an engineering test data value (within a reasonable range, the value can be taken under the condition of meeting system accuracy), which can be simulated by coupling interference into the ideal signal using a signal generator, and the K1 value is adjusted to obtain the best result; K1 is at least 1.

[0040] In the embodiments of the present disclosure, the equivalent phase difference of the phase compensation is equal to K2x phase difference; the phase difference value range is -180°~+180°; wherein K2=360 / voltage controlled oscillator operating frequency.

[0041] In practical applications, K2 is a system parameter that needs to be adjusted to a suitable value according to specific device parameters, which is proportional to the clock frequency of the system, similar to PID adjustment parameters. Taking a simple digital phase-locked loop as an example: K2=360 / voltage controlled oscillator operating frequency. If it is an analog phase-locked loop or a complex phase-locked loop, K2 value can be adjusted manually, and then the output signal and the input phase difference are measured. K2 is increased when the phase lag is increased, and K2 value is decreased when the phase lead is decreased. It can also be automatically completed by program in cooperation with a phase detection device, which has the same mechanism as manual adjustment. K2 parameter is also an engineering value (within a reasonable range, the value can be taken under the condition of meeting system accuracy).

[0042] Embodiment two

[0043] The embodiment discloses a digital filtering device for time pulses, as shown in Figure 2 which includes a signal quality analysis unit, a filter unit, and a phase-locked loop / phase synchronization unit;

[0044] The signal quality analysis unit, the filter unit, and the phase-locked loop / phase synchronization unit are electrically connected in sequence;

[0045] The signal quality analysis unit and the phase-locked loop / phase synchronization unit are electrically connected;

[0046] The signal quality analysis unit is used for signal quality evaluation of the original time synchronization pulse signal; through signal quality evaluation analysis, the filter parameters can be adjusted to cope with signal interference, and according to the signal quality, it can be inferred whether the time synchronization device has hidden troubles, prompting the staff to carry out necessary maintenance.

[0047] In the embodiments of the present disclosure, the filter unit is used for the original time synchronization pulse signal to enter the filter for filtering; the filter adjusts the filter parameters according to the signal quality evaluation result; the filter adjusts the inversion threshold of 0 and 1 according to the signal quality evaluation result; the filter flip lock and unlock time slice adjustment; by using the signal quality analysis result, the filter flip threshold and the filter time constant can be preset, so that the phase response speed can be improved; at the same time, the filter flip lock time slice and the unlock time slice can be preset, so that the strong interference false trigger condition can be eliminated.

[0048] In the embodiments of the present disclosure, as shown in Figure 3 The phase-locked loop / phase synchronization unit is used for digital phase-locked loop according to the phase of the time synchronization pulse output by the filter, and simultaneously carries out phase compensation to obtain a local time synchronization pulse, including a phase detector, a phase compensator, a loop filter, a voltage-controlled oscillator and a frequency divider; the inputs of the phase detector and the phase compensator are electrically connected with the loop filter; the loop filter, the voltage-controlled oscillator and the frequency divider are electrically connected in sequence; the output end of the frequency divider is electrically connected with the input end of the phase detector. In specific work, first, the phase detector calculates the phase difference between the local pulse and the filter output signal, then inserts the system compensation phase (simple addition operation), and this compensated data enters the loop filter for operation, then controls the voltage-controlled oscillator to obtain a high-precision clock pulse, and then the frequency divider is used to divide to obtain a local synchronous time synchronization pulse.

[0049] In the embodiments of the present disclosure, the signal quality analysis unit is used for signal quality evaluation of the original time synchronization pulse signal, including counting the interference times and pulse width of the original time synchronization pulse signal; counting the phase jitter of the original time synchronization pulse signal; and carrying out fault prediction.

[0050] In the embodiments of the present disclosure, the filter in the filter unit adjusts the filter parameters according to the signal quality evaluation result, including adjustment of the filter sliding window size and the sampling rate; the filter sliding window size is greater than 2 times the ratio of the maximum interference pulse width to the sampling rate; if the above condition cannot be met under the default sampling rate, the sampling rate can be dynamically reduced to adapt to the requirement of the sliding window size. The threshold value is equal to the sliding window size×K1×signal quality; the value range of K1×signal quality is 0.5-1.

Claims

1. A digital filtering method for time pulses, characterized in that: Perform signal quality assessment on the original time-synchronized pulse signal; The original timing pulse signal enters the filter for filtering; the filter adjusts the filtering parameters according to the aforementioned signal quality assessment results; the filter adjusts the inversion thresholds for output 0 and 1, as well as the filter flip-lock and unlock time slices, according to the aforementioned signal quality assessment results; Digital phase-locking is performed on the phase of the time synchronization pulse output by the filter, and phase compensation is performed simultaneously to obtain the local time synchronization pulse; The signal quality assessment of the original time synchronization pulse signal includes statistical analysis of the number of interferences and the pulse width of the original time synchronization pulse signal. Statistical analysis of phase jitter in the original time synchronization pulse signal; fault prediction. The adjustment of filtering parameters includes adjusting the filter sliding window size and the sampling rate; The size of the filter sliding window is greater than twice the ratio of the maximum interference pulse width to the sampling rate; If the above conditions cannot be met with the default sampling rate, the sampling rate can be dynamically reduced to adapt to the requirements of the sliding window size.

2. The digital filtering method for time pulses according to claim 1, characterized in that: The threshold is equal to the sliding window size × K1 × signal quality; the value of K1 × signal quality ranges from 0.5 to 1; where K1 is a system parameter, and the parameter value is adjusted according to the specific equipment test.

3. The digital filtering method for time pulses according to claim 2, characterized in that: The equivalent phase difference of the phase compensation is equal to K2 × phase difference; the phase difference ranges from -180° to +180°; where K2 is a system parameter, the value of which is adjusted according to the specific device, and the parameter is proportional to the clock frequency of the system.

4. A digital filtering device for time pulses, characterized in that: Includes a signal quality analysis unit, a filter unit, and a phase-locked loop / phase synchronization unit; The signal quality analysis unit, filter unit, and phase-locked loop / phase synchronization unit are sequentially electrically connected. The signal quality analysis unit and the phase-locked loop / phase synchronization unit are electrically connected; The signal quality analysis unit is used to evaluate the signal quality of the original time-synchronized pulse signal; The filter unit is used to filter the original time synchronization pulse signal; the filter adjusts the filtering parameters according to the aforementioned signal quality assessment results; the filter adjusts the inversion thresholds of output 0 and 1, as well as the filter flip-lock and unlock time slices, according to the aforementioned signal quality assessment results; The phase-locked loop / phase synchronization unit is used to digitally lock the phase of the time synchronization pulse output by the filter, and at the same time perform phase compensation to obtain the local time synchronization pulse; The signal quality analysis unit is used to evaluate the signal quality of the original time synchronization pulse signal, including statistical analysis of the number of interferences and the pulse width of the original time synchronization pulse signal. Statistical analysis of phase jitter in the original time synchronization pulse signal; fault prediction. The filter in the filter unit adjusts the filtering parameters according to the signal quality assessment results, including adjusting the filter sliding window size and sampling rate; the filter sliding window size is greater than twice the ratio of the maximum interference pulse width to the sampling rate; if the above conditions cannot be met under the default sampling rate, the sampling rate can be dynamically reduced to adapt to the requirements of the sliding window size.

5. The digital filtering device for time-synchronized pulses according to claim 4, characterized in that: The threshold is equal to the sliding window size × K1 × signal quality; the value of K1 × signal quality ranges from 0.5 to 1; where K1 is a system parameter, and the parameter value is adjusted according to the specific equipment test.

6. The digital filtering device for time-synchronized pulses according to claim 5, characterized in that: The phase-locked loop / phase synchronization unit includes a phase detector, a phase compensator, a loop filter, a voltage-controlled oscillator, and a frequency divider; the inputs of the phase detector and the phase compensator are both connected to the loop filter; the loop filter, the voltage-controlled oscillator, and the frequency divider are connected in sequence; the output of the frequency divider is connected to the input of the phase detector.

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