Detection of errors in analog signal sampling

Abstract

The invention relates to a module (1) for sampling an analog signal (S) and to a method for detecting errors when sampling an analog signal (S). In the method, the completion of each sampling of the analog signal (S) is reported to a processor (5) of the module (1) by means of a report signal (M). The processor (5) respectively generates processor signals (P) at equally spaced module time points with respect to the module time. A reference duration, which is the time interval between the generation of the processor signal (P) and the next reception of the report signal (M) by the processor (5) after the generation of the processor signal (P), is measured once. For each subsequent processor signal (P), a signal difference duration is measured, which is the time interval between the generation of the processor signal (P) and the next reception of the report signal (M) by the processor (5) after the generation of the processor signal (P). When the deviation between the signal difference duration and the reference duration exceeds the tolerance duration, an error is deduced.

Description

Technical Field

[0001] The present invention relates to a module for sampling analog signals and a method for detecting errors by the module when sampling analog signals.

[0002] In particular, the present invention relates to the sampling of analog signals by modules, wherein the module time is repeatedly synchronized with the system time. Especially in Ethernet networks, clocks are synchronized, for example, according to a synchronization protocol. This synchronization protocol is, for example, the so-called Precision Time Protocol (PTP). In this synchronization, timestamped synchronization messages are sent over the network, by means of which clocks in the network mutually calibrate their time. Typically, one clock is the so-called master clock, which specifies the master clock time for the so-called slave clocks. In particular, synchronization errors or missing synchronization of clocks in the network can lead to errors when sampling analog signals. Summary of the Invention

[0003] The purpose of this invention is to detect errors during analog signal sampling.

[0004] This objective is achieved by a method having the features of claim 1 and a module having the features of claim 10.

[0005] Advantageous improvements of the present invention are the subject of the dependent claims.

[0006] A method for detecting errors in a module for sampling analog signals at a predetermined sampling rate, according to the present invention, includes the following steps: - The module's processor is notified of the completion of each sampling of the analog signal via a report signal; - Repeatedly synchronize the module time with the system time; - The processor generates processor signals at equally spaced module time points relative to the module time, so that the difference between any two consecutive module time points is a constant module time difference. - The reference duration is measured once. The reference duration is the time interval between the generation of the processor signal and the next reception of the report signal by the processor after the generation of the processor signal. - Measure the signal difference duration for each processor signal that follows the processor signal used to measure the reference duration. The signal difference duration is the time interval between the generation of the subsequent processor signal and the next reception of the report signal by the processor after the generation of the subsequent processor signal. - Limited tolerance duration; and - An error is deduced when the deviation between the measured signal difference duration and the reference duration exceeds the defined tolerance duration.

[0007] The method of this invention is based on the concept of establishing a correspondence between the processor signal of a module's processor and the sampling of an analog signal. The processor signal is generated by the processor at equally spaced module time points relative to the module time. Therefore, the processor signal is a measure of module time. Each completion of analog signal sampling is reported to the module's processor via a report signal. Therefore, an offset of the report signal relative to the processor signal indicates that the sampling of the analog signal is no longer consistent with the module time. This method aims to detect this offset of the report signal relative to the processor signal. To this end, the method specifies a reference duration measurement, which is the time interval between the generation of the processor signal and the next reception of the report signal by the processor after the generation of the subsequent processor signal. The signal difference duration is compared with this reference duration, which is the same as the reference duration, both being the time interval between the generation of the processor signal and the next reception of the report signal by the processor after the generation of the subsequent processor signal. When the signal difference duration deviates significantly from the reference duration, i.e., the deviation exceeds a set tolerance duration, an error is inferred.

[0008] The method of the present invention preferably enables the module itself to detect erroneous sampling of analog signals, because the method is based solely on the measurement and evaluation of signals within the module (i.e., processor signals and reporting signals). In particular, the method therefore does not require a higher-level control or monitoring unit to detect erroneous sampling.

[0009] In an improved version of the method of the present invention, the module time difference is a multiple of the reciprocal of the sampling rate.

[0010] The above improvements ensure that when the sampling of the analog signal is performed error-free relative to the module time, the signal difference duration always has the same value, i.e., the reference duration value. This is necessary to enable meaningful comparison of each measured signal difference duration with the reference duration.

[0011] In another improved version of the method of the present invention, the tolerance duration is less than half the reciprocal of the sampling rate.

[0012] The above improvement aims to ensure that the tolerance duration corresponds to the correct reporting signal in each comparison, rather than to a reporting signal that is before or after that reporting signal.

[0013] In another improved version of the method of the present invention, the module time is synchronized with the system time by means of a synchronization message received by the module according to a synchronization protocol. For example, the synchronization protocol adopts the Precision Time Protocol (PTP) or the Network Time Protocol (NTP).

[0014] The above-described improvements are specifically intended for use in modules connected to networks (especially Ethernet networks).

[0015] In another improved embodiment of the method of the present invention, the analog signal is sampled by a sampling unit, which has a clock generator, and the clock generator is derived from the module time by a clock tracking unit.

[0016] The aforementioned improvement aims to correlate the sampling of analog signals with the module time. To this end, a sampling unit with a clock generator is employed, wherein the clock generator is correlated with the module time via a clock tracking unit.

[0017] In another improved version of the method of the present invention, the time interval between the processor's reception of any two consecutive report signals is recorded, and when one of these time intervals is greater than or less than a predetermined time threshold, an error in the module is inferred.

[0018] The above improvement takes into account that the time interval between any two consecutive report signals received by the processor should be at least approximately constant in time. Therefore, any deviation of this time interval from an appropriately selected time threshold also indicates that there is a missampled analog signal.

[0019] In another improvement to the method of the present invention, a response is output when an error is detected in the deduced module. This response may be, for example, an optical signal, such as a signal generated by one or more light-emitting diodes. This allows indication of erroneous sampling of the analog signal.

[0020] A module of the present invention for sampling analog signals at a predetermined sampling rate includes: - Synchronization unit, which is configured to repeatedly synchronize the module time with the system time; - A processor configured to generate processor signals at equally spaced module time points relative to the module time, such that the difference between any two consecutive module time points is a constant module time difference. - A sampling unit having a clock generator, which is derived from the module time by a clock tracking unit, and the sampling unit is configured to sample the analog signal according to the sampling rate and report the completion of each sampling of the analog signal to the processor via a report signal; - A time measurement unit configured to measure the signal difference duration for each processor signal, the signal difference duration being the time interval between the generation of a processor signal and the next reception of a report signal by the processor after the generation of that subsequent processor signal; and - An evaluation unit is configured to store the signal difference duration measured once for a processor signal as a reference duration, and compares the measured signal difference duration with the reference duration for each processor signal following the processor signal used to measure the reference duration, and infers a module error when the deviation between the measured signal difference duration and the reference duration exceeds the tolerance duration.

[0021] The module of this invention is capable of executing the method of this invention. Therefore, the advantages of the module of this invention correspond to the advantages of the method of this invention described above. Attached Figure Description

[0022] The above-described features, characteristics, and advantages of the present invention, as well as the means of realizing these features, characteristics, and advantages, will become clearer and more readily understood when further explained in conjunction with the following description of the embodiments and the accompanying drawings. The drawings show: Figure 1 A signal chain for detecting errors during the sampling of an analog signal is shown; Figure 2 A block diagram of a module used for sampling analog signals is shown.

[0023] In the accompanying drawings, corresponding parts are indicated by the same reference numerals. Detailed Implementation

[0024] Figure 1 An embodiment of the method of the present invention for detecting errors by module 1 at a predetermined sampling rate when sampling an analog signal S is shown.

[0025] Figure 2 A block diagram illustrating an exemplary embodiment of module 1 is shown. Module 1 includes a synchronization unit 3, a processor 5, a sampling unit 7, a clock tracking unit 9, a time measurement unit 11, and an evaluation unit 13.

[0026] With the help of synchronization unit 3, the module time is repeatedly synchronized with the system time T. For example, the module time is synchronized with the system time T by means of a synchronization message received by module 1 according to a synchronization protocol. As a synchronization protocol, for example, Precision Time Protocol (PTP) or Network Time Protocol (NTP) is used.

[0027] Processor 5 generates processor signals P at equally spaced module time points relative to the module time, ensuring that the difference between any two consecutive module time points is a constant module time difference. The module time difference is a multiple of the reciprocal of the sampling rate.

[0028] Clock tracking unit 9 derives the sampling clock A from the module time for the clock generator of sampling unit 7. Sampling unit 7 samples the analog signal S according to the sampling clock A tracked by clock tracking unit 9. The completion of each sampling of the analog signal S is reported to processor 5 by sampling unit 7 via report signal M.

[0029] The time measurement unit 11 measures a reference duration, which is the time interval between the generation of the processor signal P and the next time the processor 5 receives a report signal M after the generation of the processor signal P. For example, the reference duration is measured after the system has entered a stable state, such as when the difference between the master clock time and the slave clock time provided by the synchronization protocol does not exceed a predetermined time difference (e.g., 50 ns), or when the minimum number of synchronization messages specified by the synchronization protocol has been exchanged. The reference duration is stored by the evaluation unit 13.

[0030] Subsequently, the time measurement unit 11 measures the signal difference duration for each subsequent processor signal P following the processor signal P used to measure the reference duration. The signal difference duration is the time interval between the generation of the processor signal P and the next report signal M received by the processor 5 after the generation of that processor signal P. The evaluation unit 13 compares the measured signal difference duration with the reference duration, and if the deviation of the measured signal difference duration from the reference duration exceeds a set tolerance duration, the inference module 1 is considered to have encountered an error. For example, the tolerance duration is less than half the reciprocal of the sampling rate.

[0031] Optionally, the time measurement unit 11 also records the time interval between the reception of any two consecutive report signals M by the processor 5, and infers the error of module 1 when one of these time intervals is greater than or less than a predetermined time threshold.

[0032] Furthermore, when an error occurs in the inference module 1, it can output a response. For example, it can output an optical signal as a response, such as a signal generated by one or more light-emitting diodes.

[0033] Although the present invention has been illustrated and described in more detail through preferred embodiments, the present invention is not limited to the disclosed embodiments, and those skilled in the art can derive other variations based thereon without departing from the scope of protection of the present invention.

[0034] Regardless of the grammatical gender of a term, it includes individuals of masculine, feminine, or other grammatical genders.

Claims

1. A method for detecting errors in a module (1) for sampling an analog signal (S) at a predetermined sampling rate, wherein, - The processor (5) of the module (1) reports the completion of each sampling of the analog signal (S) to the module (1) via a report signal (M); - Repeatedly synchronize module time with system time (T); - The processor (5) generates processor signals (P) at module time points that are at equal intervals relative to the module time, such that the difference between any two consecutive module time points is a constant module time difference. -Measure the reference duration once, which is the time interval between the generation of the processor signal (P) and the next reception of the report signal (M) by the processor (5) after the generation of the processor signal (P); - Measure the signal difference duration for each processor signal (P) that follows the processor signal (P) used to measure the reference duration, the signal difference duration being the time interval between the generation of the processor signal (P) and the next reception of the report signal (M) by the processor (5) after the generation of the processor signal (P); -Limited tolerance duration; and - An error is deduced when the deviation between the measured signal difference duration and the reference duration exceeds the defined tolerance duration.

2. The method according to claim 1, wherein, The module time difference is a multiple of the reciprocal of the sampling rate.

3. The method according to claim 1 or 2, wherein, The tolerance duration is less than half the reciprocal of the sampling rate.

4. The method according to any one of the preceding claims, wherein, The module time is synchronized with the system time (T) using a synchronization message received by the module (1) according to the synchronization protocol.

5. The method according to claim 4, wherein, The synchronization protocol is a precision time protocol.

6. The method according to claim 4, wherein, The synchronization protocol is the Network Time Protocol.

7. The method according to any one of the preceding claims, wherein, The analog signal (S) is sampled by a sampling unit (7), which has a clock generator, and the clock generator is derived from the module time by means of a clock tracking unit (9).

8. The method according to any one of the preceding claims, wherein, Record the time interval between the processor (5) receiving any two consecutive report signals (M), and infer an error in the module (1) when one of the time intervals is greater than or less than a predetermined time threshold.

9. The method according to any one of the preceding claims, wherein, When an error is deduced in module (1), a response is output.

10. A module (1) for sampling an analog signal (S) at a predetermined sampling rate, the module (1) comprising: - Synchronization unit (3), the synchronization unit is configured to repeatedly synchronize the module time with the system time (T); - Processor (5), the processor is configured to generate processor signals (P) at equally spaced module time points relative to the module time, such that the difference between any two consecutive module time points is a constant module time difference; - Sampling unit (7), the sampling unit having a clock generator, the clock generator being derived from the module time by means of a clock tracking unit (9), and the sampling unit being configured to sample the analog signal (S) according to a sampling rate and report the completion of each sampling of the analog signal (S) to the processor (5) via a report signal (M); - Time measurement unit (11), the time measurement unit is configured to measure the signal difference duration for the processor signal (P) respectively, the signal difference duration being the time interval between the generation of the processor signal (P) and the next reception of the report signal (M) by the processor (5) after the generation of the processor signal (P); as well as - Evaluation unit (13), the evaluation unit is configured to store the signal difference duration that has been measured once for the processor signal (P) as a reference duration, and compare the measured signal difference duration with the reference duration for each processor signal (P) that follows the processor signal (P) for measuring the reference duration, and infer an error in the module (1) when the deviation between the measured signal difference duration and the reference duration exceeds the tolerance duration.

Images