CN1578197A - Clock source frequency shift detecting method - Google Patents

Abstract

The invention discloses a clock source frequency offset detection method, wherein the method is: selecting a clock source signal to be tested from multiple reference sources of network element equipment; clock, respectively counting each channel of clock source signals to be tested, and obtaining multiple counting values; calculating standard thresholds for multiple counting values, and calculating relative thresholds between multiple counting values, and calculating the obtained standard thresholds and The relative thresholds form a combined threshold in a prescribed order; use the combined threshold to query the judgment table, and at least obtain the alarm content of one of the tracking source, the main clock device crystal oscillator, and the backup clock device crystal oscillator; report the alarm content and each channel to be detected The frequency offset value of the clock source signal.

Description

Clock source frequency offset detection method

Technology threshold

The invention relates to optical communication network technology, in particular to a method for detecting frequency offset of a device clock source in an optical communication network.

Background technique

In the optical communication network, the clock plays a pivotal role in the transmission equipment, and all transmitted signals must be synchronized by the clock. The clock of the whole network should be synchronized or the deviation is within a certain range, so that the signal has good transmission quality, so many products put forward the requirement of real-time monitoring of the quality of the crystal oscillator, external synchronization reference source and line source.

At present, there are mainly two methods for detecting the clock source:

Technical solution one:

Whether the clock source is detected: When the clock source is lost, the relevant logic is used to detect that the clock source has been lost and report it, and the board software will disable the clock source. If the clock source to be damaged is the current tracking source, make a relevant instruction to enter the hold or free oscillation mode, so that the phase-locked loop enters the hold or free oscillation mode, and then use the software to select other clocks in the priority list to track, so as to keep System synchronization. Although this scheme can detect lost clock sources, it has the following disadvantages:

1. Only when the clock source is completely lost can it be detected. There is no real-time detection mechanism for the current frequency offset value of the clock source and the quality of the clock source, so the timely detection of the quality of the clock source has great limitations. For example, when the clock source is degraded to the point where it cannot be tracked, there is no corresponding detection to report the degradation status of the clock source, causing the phase-locked loop to continue to track the degraded clock; Still as a backup clock source, it is easy to cause false switching and destroy the synchronization state of the system.

2. The phase-locked loop crystal oscillator cannot be detected. The main crystal oscillator will be aged or damaged during use, which will cause the output frequency range of the crystal oscillator to shift, which will seriously cause the phase-locked loop to lose lock. However, this detection method cannot obtain the frequency offset of the crystal oscillator. Even if the crystal oscillator is aging or damaged, there will be no alarm report; when the standby crystal oscillator is aging or damaged, the main board will also not be able to know, and it is easy to cause wrong switching, resulting in clock failure after switching. Degraded performance, disrupting system synchronization.

Technical solution two:

This scheme is a majority voting clock source detection method. The majority vote judges whether the clock source is good or bad is based on the majority of correct clock sources. In frequency offset detection, since there is no absolutely accurate clock as a reference, there is no way to directly obtain the absolute frequency value of each clock source. Therefore, to obtain more accurate frequency offset data, the relative frequency difference between each clock source can only be used as the basis for judgment. Then the accurate clock source is selected by majority vote, and the frequency offset value of other sources is obtained based on it. According to the principle of majority voting, most of the detected frequencies are in the same frequency range as accurate frequency values, while the remaining few frequencies outside the range have frequency deviations. The majority vote is to judge whether the reference source and the crystal oscillator belong to the majority accurate or the minority error through the set threshold range, so as to judge the quality of the clock source. The majority vote uses a simple two-dimensional table to judge the pros and cons of the clock sources in the table. Its main principle is that most clock sources at the same quality level are high-quality, while a few clock sources at other quality levels are inferior .

Technical scheme two has the following disadvantages:

1. The phase-locked loop crystal oscillator cannot be detected. The main crystal oscillator is aged or damaged during use, which causes the output frequency range of the crystal oscillator to shift, resulting in the loss of lock of the phase-locked loop. This detection method cannot obtain the pros and cons of the crystal oscillator, even if the crystal oscillator is aging or damaged, there will be no alarm report, which will destroy the system synchronization. When the standby crystal oscillator is aging or damaged, the main board cannot know it, and it is easy to cause wrong switching, resulting in the degradation of the clock performance after the switching, and destroying the synchronization of the system.

2. In the judgment, most sources are regarded as normal clock sources by default. There are many problems in this judgment standard. First of all, when there are few clock sources, the judgment cannot be made or the judgment is inaccurate. For example, there are only two reference sources, how to judge that most of them are normal. Secondly, when most of the reference sources are damaged, the judgment standard will be greatly affected, and the phase-locked loop will make a mistake in selecting the reference source.

3. Only the advantages and disadvantages of the clock source can be reported, but the real-time frequency deviation value of the clock source cannot be obtained, and the specific data of the clock source deviation cannot be known in time.

4. There are strict restrictions on the number of clock sources to be detected. Once the number of clock sources exceeds the predetermined limit, it will not be possible to detect redundant clock sources. This requires different judgment mechanisms for different configurations, and the diversified configuration of system clocks cannot be guaranteed. Get compatibility detection mechanism.

Contents of the invention

The object of the present invention is to provide a clock source frequency offset detection method to solve the shortcomings of the prior art that cannot timely and accurately detect the clock source frequency offset and the quality of the crystal oscillator.

The invention provides the following technical solutions:

A clock source frequency offset detection method, used to detect clocks and crystal oscillators of network element equipment in a synchronous network system; the method includes steps:

A. Select the clock source signal to be tested from the multi-channel reference sources of the network element equipment;

B. Using the clock signal of the main clock device in the network element device as the counting clock, counting each clock source signal to be tested respectively, and obtaining multi-channel counting values;

C. Calculating standard thresholds for the multi-channel count values and calculating the relative thresholds between the multi-channel count values respectively, and forming the combined thresholds in a prescribed order with the obtained standard thresholds and relative thresholds;

D. Use the combination threshold to query the judgment table, and at least obtain the alarm content of one of the tracking source, the main clock device crystal oscillator and the standby clock device crystal oscillator;

E. Report the alarm content and the frequency offset value of each clock source signal to be detected.

in:

When the clock source signal to be tested includes an independent source, in step D, determine whether the independent source is good or bad according to the standard threshold of the independent source, and report in step D.

When there are tracking sources and backup clock devices in the network element device, the clocks of the tracking source and backup clock devices are selected first. If multiple clock sources need to be detected on the same device, only the clock source with the highest priority and existing clock source is detected.

The multiple clock source signals in step A include at least all clock source signals configured in the clock source priority list.

When the number of clock sources in the priority list is less than a predetermined value, an existing clock source is automatically searched for as a reference source.

The independent sources contained in the clock source signal to be tested are selected according to the order of priority from high to low in the clock source priority list.

When there are independent sources in the clock source priority list that are not selected to participate in the query judgment table:

In step B, the independent source signals are also counted in turn;

In step C, the count value is also compared with a predetermined standard value to obtain the frequency offset value of each independent source;

In step D, it is also determined whether the independent source is good or bad according to the frequency offset value; and

In step E, the quality and frequency offset values of these independent sources are reported.

The present invention can timely and effectively detect each clock source in the priority list and the output frequency range of the phase-locked loop crystal oscillator, and achieve accurate alarm, clock source switching, and main-standby crystal oscillator switching through related processing; At the same time, various clock sources and frequency offset data are provided, and the accuracy can be adjusted according to the number of digits of the counter; and it has good compatibility with different configuration clock systems, and is suitable for priority lists of various configurations.

Description of drawings

1A and 1B are structural diagrams of a frequency offset detection module;

Figure 2 is a timing diagram of the counter;

Fig. 3 is the main judgment flow chart of tracking source and standby equipment crystal oscillator;

Fig. 4 is the main judgment flow chart of independent source and standby equipment crystal oscillator;

Fig. 5 is the flow chart of the main judgment of the tracking source and the independent source;

Fig. 6 is a flow chart of the main judgment of the fully independent source.

Detailed ways

In a synchronous network system, the clock of the network element equipment is phase-locked to the reference source through the digital phase-locked loop to output the system clock. For the crystal oscillator, there is a voltage control range. Within the voltage control range, the frequency of the crystal oscillator is proportional to the voltage control voltage. Linear relationship, beyond the range of voltage control into a nonlinear relationship. Therefore, when designing the phase-locked loop, it is considered to make the crystal oscillator work within the voltage control range to ensure the accuracy of the output frequency. For example, the range of the digital-to-analog conversion value (hereinafter referred to as DA value) of the digital phase-locked loop of the device is set as A˜B. Once the reference source has a frequency offset, the DA value will change with the offset direction and continue to track, but if the frequency offset exceeds the controllable range of the DA value, the phase-locked loop will lose lock, and the DA value will be offset by the reference frequency. The direction is set to the maximum value B or the minimum value A, which is an important basis for frequency offset detection.

The clock of the backup device tracks the clock of the master device through an analog phase-locked loop, so it should also be synchronized with the master clock under normal conditions. The backup device outputs a feedback clock signal to the master device for active/standby interlocking, so this clock signal can be used to determine the locking status of the active and standby boards.

Generally, multiple clock sources are configured in the clock source priority list of the device (the clock of the standby device is included in the existing clock source, but not included in the priority list). During normal operation, the main clock tracks the clock source with the highest priority. This clock source is called a tracking source, and the remaining clock sources that are not tracked are called independent sources. For independent sources, the DA value range of the crystal oscillator can be used to judge whether it can be tracked. If the reference source frequency is within the DA value range, it can be tracked. If it exceeds this range, it cannot be tracked. This is also a theoretical basis for frequency offset detection. The pulling range of the standard crystal oscillator should be -4.6～+4.6PPM according to the standard. In this embodiment, the pulling range of the crystal oscillator for frequency offset detection is set at -5～+5PPM.

The invention takes the crystal oscillator output of the main clock device as a reference, counts the reference source signal to be detected and the output signal of the crystal oscillator, and obtains relevant information through the count value.

Referring to FIG. 1A, the logic part of the frequency offset detection module includes a selection register, a counter and an output interface. The selection register is used to receive multiple reference source signals, and select the clock signal output to be detected; the counter receives the clock signal output by the selection register and counts it, and then outputs the count value through the output interface. The counting clock input terminal of the counter is connected with the crystal oscillator output of the main clock device, and the output signal of the crystal oscillator of the main clock device is used as the counting clock.

As shown in Figure 1B, since high-performance devices are required for counting signals with high frequencies, in order to reduce the requirements for device performance, a frequency divider is connected to the input of the selection register, so that the reference source signal becomes a low-frequency signal after frequency division . Similarly, a frequency divider is connected between the counting clock input terminal of the counter and the crystal oscillator output terminal of the main clock device, and the frequency-divided output signal of the crystal oscillator is used as the counting clock.

The present invention will be described in detail below by taking FIG. 1B as an example.

Referring to FIG. 1B , the selection registers are five 32-to-1 selection registers, and five channels are selected from multiple reference sources as signals to be tested. The selection register is a programmable logic device, which realizes some logic functions, such as the selection and allocation of the clock source. The selection register receives relevant control commands of the processor through the interface.

The counters are five 16-bit counters, and each counter uses the frequency-divided signal output by the crystal oscillator of the master device as the counting clock to synchronously count one channel of the signal to be tested. Refer to the timing sequence of the counter shown in Figure 2. Taking the counting accuracy of 0.1PPM as an example, the crystal oscillator output of the device is 10M, and the low-frequency clock signal to be tested is 1K, so 1000 1K cycles need to be counted (1000/(10000000*1000)=0.1 PPM), so the counter first counts 1000 1K cycles through the 10M falling edge, and generates a register read enable signal CNT-REFRESH with a pulse width of two cycles when counting to 1001, and reads the counter through the 10M rising edge; then generates a pulse width of two The periodic counter clearing enable signal CNT-CLEAR clears the counter through the 10M falling edge. The counting data is kept in the register until the next reading (the following descriptions are based on this example).

A register can be set at the output end of each counter to temporarily store the count value output by the counter for reading by the processing module in the device. When there is no register, the count value can be read through the processing module through the interrupt signal when the counter finishes counting.

The main working process of frequency offset detection is as follows:

(1) There are multiple clock source signals on the network element equipment, including external synchronization sources, line sources, and backup clock crystal oscillators. These clock sources become low-frequency clock signal input selection registers after frequency division.

The clock sources configured in the clock priority list of network element devices should be used as input. If there are less than 4 clock sources in the priority list plus the clock source of the backup clock device, it will automatically search for existing clock sources as input.

(2) 5 selectors select 5 channels of signals to be tested according to the priority of the clock source in the priority list.

Since the clock of the standby clock device is not in the priority list, this clock source should be selected as long as it exists. For independent sources, they are selected in descending order of their priority in the priority list.

(3) The 5-channel counting counts the 5-channel signals to be tested respectively, and outputs the count values A1, A2, A3, A4, A5, and then calculates the standard threshold value for the first four-channel count values A1, A2, A3, A4, and then calculates For relative thresholds of relative values A1-A2, A1-A3, A1-A4, A2-A3, A2-A4, A3-A4, standard thresholds and relative values are combined in a certain order to form combined thresholds.

a. Standard threshold: According to the above example, it is to calculate the count value output by the counter and the standard value of the hexadecimal number 9680H (9680H is the hexadecimal value obtained by counting the signal of 10M from the motherboard crystal oscillator output, that is, 1K and 10M are synchronized The frequency range in which the difference of the count value at time is located. This difference reflects the frequency difference between the two frequencies, converted into PPM is equivalent to every difference of 1 corresponds to a difference of 0.1PPM between the two frequencies.

b. Relative threshold: the frequency range in which the difference between two counter outputs is located.

According to the size of the frequency offset value, it is divided into five threshold ranges:

Threshold -3 means: difference <= -5PPM;

Threshold -2 means: -5PPM<difference<-0.3PPM;

Threshold 1 means: -0.3PPM<=difference<=0.3PPM;

Threshold +2 means: 0.3PPM<difference<5PPM;

Threshold +3 means: difference >= 5PPM; where 5PPM represents the locking range of the crystal oscillator.

Calculating the standard threshold value is: first calculate the difference between the first four count values A1, A2, A3, A4 and the standard value 9680H; calculate the frequency offset value corresponding to each difference value; get the corresponding value according to the range of each frequency offset value standard threshold.

Calculating the relative threshold is: calculating the frequency offset values corresponding to the relative values A1-A2, A1-A3, A1-A4, A2-A3, A2-A4, A3-A4; relative threshold.

For example: the calculated standard thresholds are: 1, -2, 2, -3, and the calculated relative thresholds are: 2, -2, -2, 2, 1, 2, then these values are formed into a combination threshold in order : 1-22-32-2-2212.

(4) Use the combined threshold to query the judgment table to obtain the alarm content of the status of the crystal oscillator and the clock source.

The judgment table is only used to judge whether the current tracking source, mainboard crystal oscillator, and backup board crystal oscillator are good or bad. The content of the judgment table is mainly divided into two parts: threshold and alarm. It is formed by using majority voting, PLL characteristics and system characteristics. and the characteristics of the lower limit; system characteristics are the processing methods of transmission products for clocks, such as source selection, backup, switching, etc. Each group of combined thresholds corresponds to an alarm in the decision table, and the quality of the crystal oscillator and clock source is obtained through the alarm. For example: look up the corresponding alarm signal from the corresponding decision table for the combination threshold 1-22-32-2-2212 in the previous step.

(5) The fifth counter output A5 is specially used to detect independent sources in the priority list that are not selected to participate in querying the decision table. The counting result is not used as the basis for the decision table, but is only used to report the frequency offset value of the detection source.

The clock sources in the priority list will enter the first 4 counters in order, complete the table lookup of the judgment table, and obtain corresponding alarms and processing. Since the four counters can only have 3 clock sources except the crystal oscillator of the standby device, but there may be more than 3 clock sources configured in the priority list, so other additional clock sources (independent sources) will not be detected. Therefore, the fifth counter is used to perform rotation detection on these sources, that is to say, the clock source in this counter is not fixed. For example: there are 5 clock sources in the priority list, 3 clock sources are judged in the judgment table, and the remaining 2 clock sources are counted in the counter of the 5th clock source, one channel is counted for a period of time, and the other channel is counted for a period of time, so that the rotation , compare the counted value with the normal source at each count, if the difference is within the range that meets the requirements, the source is good, and if it exceeds the range, the source is bad.

Processing principles for independent sources:

Whether the independent source is good or not is judged by whether the independent source is within the locking range of the mainboard crystal oscillator: whether the DA value converted from the crystal oscillator DA value of the current main clock device + the PPM value of the independent source offset is within the locking range of the mainboard crystal oscillator (A～ B), if it is within the locking range, the independent source is normal, otherwise, the frequency deviation of the independent source is too large.

The method of converting PPM value to DA value:

DA value = PPM value * coefficient = (count value/10) * coefficient;

Coefficient = (Upper Limit of Locking Range - Lower Limit)/(Crystal Pulling Range*2)

Among them: the pulling range is related to the crystal oscillator, and it is required that the pulling range must be greater than the pulling range of the judgment table.

When the crystal oscillator of the main clock device is normal, it means that the output frequency of the crystal oscillator is accurate and can be used as the reference frequency. At this time, the frequency deviation of each clock source is calculated according to the output of the counter, and the specific value can be queried through the command line; but when the crystal oscillator is detected to be broken, If there is no accurate reference source, stop calculating the frequency offset.

(6) Finally, the frequency offset value of each detection source and the alarm generated by the look-up table are automatically reported to the computer, and corresponding operations are performed.

The drafting principle of the judgment table in this embodiment:

In actual situations, the device is usually equipped with a master clock device (hereinafter referred to as the main board) and a backup clock device (hereinafter referred to as the standby board), and multiple clock sources are configured in the clock source priority list (the main clock tracking priority in normal operation The clock source with the highest level is called the tracking source, and the rest of the untracked sources are called independent sources). But there may also be: no standby board with only one clock device; free oscillation without tracking source; and no tracking source and no standby board. Moreover, the number of clock sources in the priority list is also uncertain. Therefore, the judgment table can be divided into four types by type: with tracking source and backup board, without tracking source and backup board, with tracking source but no backup board, without tracking source and no backup board. Each type is divided into binary, ternary, and quaternary judgment tables according to the number of clock sources participating in the judgment.

The content of the judgment table is mainly divided into two parts: threshold and alarm.

The method of judging the locking situation by the threshold value is as follows:

(1) Threshold of the tracking source: 1~ indicates that the tracking is normal; 2~ indicates that the tracking source is out of the traction range, the motherboard crystal frequency is pulled to the highest, and 0.3PPM < difference < 5ppm; -2 ~ indicates that the tracking source is out of the traction range, The motherboard crystal frequency is pulled to the lowest, and -5PPM<difference<0.3PPM; 3～indicates that the tracking source is out of the traction range, the motherboard crystal frequency is pulled to the highest, and the difference＞=5PPM; -3～indicates that the tracking source is out of the traction range, The motherboard crystal frequency is pulled to the lowest, and the difference is <=-5PPM.

(2) Threshold of the crystal oscillator on the standby board: 1~ indicates that the tracking is normal; 2~ indicates that the lock is lost, the frequency of the crystal oscillator on the main board exceeds the pulling range of the crystal oscillator on the backup board, and the crystal oscillator on the backup board is pulled to the lowest level, and 0.3PPM < difference < 5ppm; -2 ～Indicates that the lock is lost, the frequency of the main board crystal oscillator exceeds the range of the crystal oscillator of the backup board, and the crystal oscillator of the backup board is pulled to the highest level, and -5PPM＜difference＜0.3PPM; The crystal oscillator is pulled to the lowest level, and the difference is >= 5PPM; -3~ indicates that the lock is lost, the frequency of the main board crystal oscillator is beyond the pulling range of the backup board crystal oscillator, and the backup board crystal oscillator is pulled to the highest, and the difference is <= -5PPM.

(3) Whether the independent source and the motherboard crystal oscillator can be locked: whether the DA value converted from the current DA value of the motherboard crystal oscillator + the PPM value of the independent source offset is within the locking range of the motherboard crystal oscillator (A～B).

(4) Whether the tracking source, independent source and the crystal oscillator of the standby board can be locked: whether the tracking source and independent source are within the crystal oscillator locking range of the standby board.

(5) Whether the tracking source is consistent with the independent source: 1 ~ the description is consistent; 2 ~ the description is inconsistent, but the difference is not big; -2 ~ the description is inconsistent, but the difference is not big; 3 ~ the description is inconsistent, the difference is large; -3 ~ The descriptions are inconsistent and quite different.

Referring to the judgment flow charts of Fig. 3, Fig. 4, Fig. 5 and Fig. 6, each flow chart is the main basis for making the flow chart of this type of judgment table.

Refer to Figure 3: The main judgment process of tracking source and standby crystal oscillator is as follows:

Step 300: Determine whether the tracking source is out of lock, if not, go to step 301, otherwise go to step 304;

Step 301: judging whether the main and standby boards are out of lock, if not, then determine that the main and standby boards are normal (step 302), otherwise determine that the crystal vibration of the standby board is broken (step 303);

Step 304: Determine whether the tracking source is within the locked range of the crystal oscillator on the standby board, if not, proceed to step 305, otherwise determine that the main board crystal oscillator is broken (step 306);

Step 305: judge whether most of the independent sources are within the locking range of the motherboard crystal oscillator, if not, proceed to step 307, otherwise determine that the tracking source is broken (step 308);

Step 307: judging whether most independent sources are in the crystal oscillator locking range of the backup board, if not, proceed to step 309, otherwise determine that the main board crystal oscillator is broken (step 410);

Step 309: judging whether there is a reference source within the locking range of the motherboard crystal oscillator, if not, proceed to step 311, otherwise determine that the tracking source is broken (step 312);

Step 311: Determine whether there is a reference source within the crystal oscillator locking range of the standby board, if not, determine that the crystal oscillator of the main board is broken (step 313), otherwise determine that the crystal oscillator of the standby board is broken (step 314).

Referring to Figure 4, the main judgment process of the independent source and standby crystal oscillators is as follows:

Step 200: Determine whether the main and standby boards are out of lock, if not, go to step 201, otherwise go to step 208;

Step 201: judging whether there is an independent source within the crystal oscillator locking range of the motherboard, if not, proceed to step 202, otherwise proceed to step 203;

Step 202: Judging whether there is an independent source within the crystal oscillator locking range of the standby board, if not, then carry out independent source detection (step 204); otherwise, perform active-standby switchover (step 205);

Step 203: judge whether the independent source frequency is the same, if not then determine that the active and standby boards are normal (step 206), otherwise determine that the source is inconsistent (step 207);

Step 208: Determine whether there are fewer independent sources within the locking range of the motherboard crystal oscillator than the standby crystal oscillator, if not, determine that the primary crystal oscillator of the standby board is damaged (step 209), otherwise determine that the motherboard crystal oscillator is damaged (step 210).

Referring to Figure 5, the main judgment process of tracking source and independent source is as follows:

Step 10: Determine whether the tracking source is out of lock, if not, go to step 20, otherwise go to step 30;

Step 20: determine whether the frequency of the tracking source and the independent source are the same; if so, determine that the tracking source is normal (step 22); otherwise determine that the source is inconsistent (step 21);

Step 30: Determine whether there is an independent source within the crystal oscillator locking range of the main board; if yes, determine that the tracking source is broken (step 32); otherwise, determine that the main clock device crystal oscillator is broken (step 31).

Referring to Figure 6, the main judgment process of the fully independent source is as follows:

Step 100: judging whether most of the independent sources are within the crystal oscillator locking range of the motherboard; if yes, proceed to step 120, otherwise proceed to step 110;

Step 110: judging whether the frequency of most independent sources is consistent; if so, then carry out independent source detection (step 112), otherwise determine that the crystal vibration of the main clock device is broken (step 111);

Step 120: Determine whether the frequency of the independent source is consistent; if yes, perform independent source detection (step 122), otherwise determine that the independent source is normal (step 121).

The principle of binary table imitation:

Number of binary table reference sources: 2

Threshold allocation: the first bit is the threshold of reference source 1 (threshold of (count value of reference source 1-9680H)); the second bit is the threshold of reference source 2; the third bit is the threshold of reference source 1-reference source 2.

Four table types:

1. Tracking source + spare board crystal oscillator

Example: "111" tracking is normal.

Warning: normal.

"222" The crystal oscillator of the main board cannot track the reference source, and the tracking source is within the locked range of the crystal oscillator of the backup board.

Warning: The motherboard crystal oscillator is broken.

"12-2" The main board's crystal oscillator is tracking normally, and the backup board's crystal oscillator is out of lock.

Warning: The crystal oscillator of the standby board is broken.

2. Independent source + spare board crystal oscillator

Example: "111" is locked normally, and the independent source is within the crystal oscillator locking range of the motherboard.

Warning: normal.

"212" is locked normally, and the independent source is within the crystal oscillator locking range of the main board.

Warning: normal.

"22-2" The main and standby boards are out of lock, and the independent source is within the locking range of the local crystal oscillator.

Warning: The crystal oscillator of the standby board is broken.

"322" The main and standby boards are out of lock, and the independent source is within the locking range of the local crystal oscillator.

Warning: The motherboard crystal oscillator is broken.

3. Tracking source + independent source

Example: "111" tracking is normal, and the independent source is within the crystal oscillator locking range of the motherboard.

Warning: normal.

"2-22" The motherboard crystal oscillator cannot track the reference source, and the independent source is within the lock range of the motherboard crystal oscillator.

Warning: Reference source 1 bad.

"221" The motherboard crystal oscillator cannot track the reference source, and the independent source is not within the lock range of the motherboard crystal oscillator.

Warning: The motherboard crystal oscillator is broken.

4. Independent source + independent source

Example: "111" independent source is within the crystal oscillator locking range of the motherboard.

Warning: normal.

"2-22" The independent source is within the crystal oscillator locking range of the motherboard, and the clock source is inconsistent.

Warning: Inconsistent sources.

"331" independent sources are not within the scope of the motherboard crystal oscillator lock.

Warning: The motherboard crystal oscillator is broken.

Three-dimensional table virtual principle:

List principle: same as binary list

Number of ternary table reference sources: 3

Threshold distribution: the first digit is the threshold of reference source 1; the second digit is the threshold of reference source 2; the third digit is the threshold of reference source 3; the fourth digit is the threshold of reference source 1-reference source 2; the fifth digit It is the threshold value of reference source 2-reference source 3; the sixth bit is the threshold value of reference source 1-reference source 3.

Four table types:

1. Tracking source + independent source + standby board crystal oscillator

For example: "2-212-21" motherboard crystal oscillator cannot track the reference source, and the independent source is within the lock range of the motherboard crystal oscillator.

Warning: Reference source 1 bad.

"11-2122" The main board's crystal oscillator is tracking normally, and the backup board's crystal oscillator is out of lock.

Warning: The crystal oscillator of the standby board is broken.

"222122" The crystal oscillator of the main board cannot track the reference source, and the tracking source is within the locked range of the crystal oscillator of the backup board.

Warning: The motherboard crystal oscillator is broken.

2. Two independent sources + standby board crystal oscillator

For example: "22-3133" the main board and the standby board are out of lock, and the independent source is within the crystal oscillator lock range of the main board.

Warning: The crystal oscillator of the standby board is broken.

"332122" The active and standby boards are out of lock, and the independent source is within the locking range of the crystal oscillator.

Warning: The motherboard crystal oscillator is broken.

3. Tracking source + two independent sources

Example: "2-2-2212" motherboard crystal oscillator cannot track the reference source, and the independent source is within the lock range of the motherboard crystal oscillator.

Warning: Reference source 1 bad.

"222111" The motherboard crystal oscillator cannot track the reference source, and the independent source is not within the lock range of the motherboard crystal oscillator.

Warning: The motherboard crystal oscillator is broken.

4. Three independent sources

Example: "2-222-21" independent source is within the crystal oscillator locking range of the motherboard, and the clock source is inconsistent.

Warning: Inconsistent sources.

"333111" independent sources are not within the scope of the motherboard crystal oscillator lock.

Warning: The motherboard crystal oscillator is broken.

Quaternary Table Simulation Principles:

List principle: same as binary list

Quaternary table reference source number: 4

Threshold allocation: the first digit is the threshold of reference source 1; the second digit is the threshold of reference source 2; the third digit is the threshold of reference source 3; the fourth digit is the threshold of reference source 4; the fifth digit is the threshold of reference source 1 - the threshold of reference source 2; the sixth bit is the threshold of reference source 1-reference source 3; the seventh bit is the threshold of reference source 1-reference source 4; the eighth bit is the threshold of reference source 2-reference source 3; The nine digits are the threshold value of reference source 2-reference source 4; the tenth digit is the threshold value of reference source 1-reference source 4.

Four table types:

1. Tracking source + two independent sources + standby crystal oscillator ("*" stands for any threshold)

For example: "2-21-2 ^****** " The motherboard crystal oscillator cannot track the reference source, and the independent source is within the lock range of the motherboard crystal oscillator.

Warning: Reference source 1 bad.

“1113 ^**** ” The main board’s crystal oscillator is tracking normally, and the standby board’s crystal oscillator is out of lock.

Warning: The crystal oscillator of the standby board is broken.

“2222111 ^*** ” The crystal oscillator of the main board cannot track the reference source, and the tracking source is within the locked range of the crystal oscillator of the backup board.

Warning: The motherboard crystal oscillator is broken.

2. Three independent sources + standby board crystal oscillator

For example: "222-211 ^* 1 ^** " The main board and the standby board are out of lock, and the independent source is within the crystal oscillator lock range of the main board.

Warning: The crystal oscillator of the standby board is broken.

“333111 ^*** ” The main and standby boards are out of lock, and the independent source is within the locking range of the crystal oscillator.

Warning: The motherboard crystal oscillator is broken.

3. Tracking source + three independent sources

Example: "2-2-22 ^****** " The motherboard crystal oscillator cannot track the reference source, and the independent source is within the lock range of the motherboard crystal oscillator.

Warning: Reference source 1 bad.

"2222111111" The motherboard crystal oscillator cannot track the reference source, and the independent source is not within the lock range of the motherboard crystal oscillator.

Warning: The motherboard crystal oscillator is broken.

4. Four independent sources

For example: "2-222 ^****** " The independent source is within the crystal oscillator locking range of the motherboard, and the clock source is inconsistent.

Warning: Inconsistent sources.

"333111 ^**** " independent sources are not within the scope of the motherboard crystal oscillator lock.

Warning: The motherboard crystal oscillator is broken.

Alarm content:

According to the judgment table to determine whether the tracking source and the crystal oscillator are good or bad, a series of alarms and related processing need to be reported. The judgment table lists a total of 25 alarms according to various situations.

The realization of the software module part of this embodiment:

The main function of the software is to select the corresponding judgment table according to the current clock source, assign the threshold value according to the frequency deviation of each clock source, and search the processing method from the judgment table according to the threshold value.

The judgment table is divided into four types according to the type. In the software, they are respectively: 0 means no tracking source, no backup board; 1 means tracking source, no backup board; 2 means no tracking source, backup board; 3 means tracking source , with a spare board. Each type of judgment table corresponds to: 4-element table, 3-element table, and 2-element table. Select the type and dimension of the judgment table according to the clock source. Preferentially choose a 4-element table, a judgment table with a tracking source, and a backup board.

Detection range: the clock source in the status of the priority list, the crystal oscillator of the main board, and the crystal oscillator of the backup board.

Source selection principle:

1) If there are multiple clock sources to be detected on the same device, only the clock source with the highest priority and existing is detected.

2) If there are less than 4 clock sources, automatically search for existing clock sources and add them to the detection list to participate in the judgment process.

Counting principle: The hardware provides 5 counters, of which the first 4 are used to count the clock source of the decision table, and the last one is used to count the frequency deviation of the independent source. If there are multiple independent sources, the last counter is used to count alternately. There must be a change of 1 when counting. In order to avoid jitter at the boundary, the difference between the two counts before and after is 1, and the count result of the previous count is still sent to the frequency offset detection.

Table lookup principle: In order to increase the speed of table lookup and minimize the size of the table, each judgment table is divided into multiple small tables. The processing results of different relative value combinations of clock sources are stored in the small table.

1) First search for the corresponding small table according to the type of the table and the threshold value of the clock source.

2) Find the corresponding processing results in the table according to the threshold value of the relative value between each clock source.

In order to avoid erroneous judgments during the process from losing lock to locking, the table lookup result must be filtered multiple times, for example, 5 times.

In the present invention, the number of selection registers and counters is not limited to 5, which can be increased or decreased as needed; according to the number of clocks participating in the judgment, the judgment table can also be a five-element table, etc.

Claims (18)

1, a kind of clock source frequency bias detecting method is used for detecting the clock and the crystal oscillator situation of synchronous network system network element device; It is characterized in that comprising step:

A, from the multichannel reference source of network element device, select clock source signals to be measured;

B, with the clock signal of active clock equipment in the network element device as counting clock, respectively to each road clock source signals counting to be measured, and obtain the multiple metering value;

C, respectively to multiple metering value basis of calculation threshold value, and calculate the mutual relative threshold of multiple metering value respectively, and with the level threshold value of gained and relative threshold in accordance with regulations order constitute combined threshold value;

D, utilize described combined threshold value inquiry decisional table, obtain the warning content of one of tracing source, active clock equipment crystal oscillator and standby clock equipment crystal oscillator at least;

E, report the frequency offseting value of described warning content and each road tested clock source signals.

2, the method for claim 1, it is characterized in that, when having tracing source and standby clock equipment in the network element device, preferentially select tracing source and standby clock equipment clock, if have a plurality of clocks source to need to detect on the same equipment, then only detect the clock source that priority is the highest and exist.

3 the method for claim 1 is characterized in that, the multichannel reference clock source signal described in the steps A comprises at least and is configured in all clock source signals in the priority list of clock source.

4, method as claimed in claim 3 is characterized in that, when the clock source quantity in the priority list was less than predetermined value, the clock source of search existence was as the reference source automatically.

5, method as claimed in claim 3 is characterized in that, the independent source that comprises in the described clock source signals to be measured is selected by clock source priority list medium priority order from high to low.

6, the method for claim 1 is characterized in that, when comprising independent source in the clock source signals to be measured, determines the quality of independent source according to the level threshold value of independent source in step D, and reports in step D.

7, method as claimed in claim 3 is characterized in that, when not being selected for the independent source that participates in the inquiry judging table in the priority list of clock source in addition:

In step B, also in turn described independent source signal is counted;

Also count value and preassigned numeric ratio are obtained the frequency offseting value of each road independent source among the step C;

Also determine the quality of independent source among the step D according to described frequency offseting value; And

Report the quality and the frequency offseting value of these independent sources in the step e.

8, as claim 6 or 7 described methods, it is characterized in that, the quality of independent source is by judge whether " the current frequency values of active clock equipment crystal oscillator+independent source frequency offseting value " is determined in the lock-in range of active clock equipment crystal oscillator, if in lock-in range, determine that then this independent source is normal; Otherwise, determine that this independent source frequency deviation is excessive.

9, the method for claim 1 is characterized in that, steps A comprises step:

A1, multipath clock source signal frequency division is obtained the multichannel low frequency signal;

A2, from the multichannel low frequency signal, select clock source signals to be measured.

10, as claim 1 or 9 described methods, it is characterized in that, among the step B, with behind the output clock division of active clock equipment crystal oscillator as counting clock.

11, the method for claim 1 is characterized in that, step C comprises step:

Respectively with each a road count value and a preassigned numerical computations difference with calculate each road count value relative difference each other;

Calculate the frequency offseting value of each difference and relative difference correspondence;

According to the frequency deviation range under the frequency offseting value, obtain the level threshold value of difference correspondence and the relative threshold of relative difference correspondence.

12, as claim 7 or 11 described methods, it is characterized in that the count value that described preassigned numerical value counts to get the active clock equipment clock for the counting clock that adopts and the active clock equipment clock is synchronous.

13, the method for claim 1 is characterized in that, described decisional table utilizes majority voting, phase-locked loop characteristics and system clock processing method characteristic comprehensively to form.

14, the method for claim 1, it is characterized in that described decisional table is divided into according to tracing source and standby clock equipment situation has tracing source to have standby clock equipment, no tracing source that standby clock equipment is arranged, have tracing source not have standby clock equipment, no tracing source does not have four types of standby clock equipment.

15, method as claimed in claim 14, it is characterized in that, every type decisional table is divided into binary, ternary, quaternary decisional table and polynary judgement table by the number that participates in judgement clock source, and described decisional table comprises the described level threshold value in clock source and threshold value part and the alarm part that described relative threshold of respectively adjudicating the clock source is formed of respectively adjudicating.

16, method as claimed in claim 15 is characterized in that, described each decisional table is made up of the identical little table of a plurality of structures, and described little table is being deposited the alarm of the different relative threshold combination in clock source.

17, method as claimed in claim 15 is characterized in that, when inquiring about described decisional table, at first according to the type selecting decisional table type in clock source, selects the dimension of decisional table according to the number in clock source.

18, method as claimed in claim 17 is characterized in that, preferentially selects 4 yuan of decisional tables or/and tracing source is arranged, the decisional table of slave board is arranged.

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