Difference detector unit and automatic control system including same
By dynamically adjusting the control algorithm parameters of the automatic control system using a differential detector unit, the balance between responsiveness and delay in the existing system is solved, thereby improving the stability of the output signal and the auditory experience.
Patent Information
- Application Number
- CN202510716617.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-06-25
- Filing Date
- 2025-05-30
- Publication Date
- 2025-12-26
AI Technical Summary
Existing automatic control systems are either not fast enough or too fast in response to changes in input signals, resulting in unstable output signals, which affects the auditory experience. Furthermore, it is difficult to balance responsiveness and delay constraints in real-time applications.
A differential detector unit is introduced to dynamically adjust the parameters of the control algorithm, such as the start time and release time, to adapt to changes in the input signal by calculating the average difference of the signal parameters over different time intervals.
It improves the responsiveness and accuracy of automatic control systems, ensures the stability of output signals, enhances the auditory experience, and meets the latency requirements of real-time applications.
Smart Images
Figure CN121209323A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a delta detector unit and an automatic control system comprising the delta detector unit. BACKGROUND
[0002] An automatic control system is generally capable of controlling at least one parameter of an input signal such that at least one parameter of the resulting output signal equals a desired value or falls within a desired range of values. Such an automatic control system can be implemented as a feedback or feedforward control system. The purpose of such a system is to ensure that certain signal parameters of the output signal remain constant regardless of changes in signal parameters of the input signal. The automatic control system generally monitors the output signal (feedback system) or the input signal (feedforward system) and uses a control algorithm to adjust the respective parameters to maintain the desired value or the desired range of values. Certain parameters of such a control algorithm, e.g. attack time and release time, are preset and will then be used later by the control algorithm. Such parameters are generally set to produce the best possible result. There is a need for an automatic control system that produces a better result compared to known systems. SUMMARY
[0003] A delta detector unit is configured to determine an average value of a signal parameter of an input signal of an automatic control system over a first time interval, to determine an average value of the signal parameter of the input signal over a second time interval, to determine a difference between the average value of the signal parameter over the first time interval and the average value of the signal parameter over the second time interval, and to indicate to the automatic control system to adapt at least one parameter of a control algorithm of the automatic control system if the determined difference exceeds a defined first threshold value or falls below a defined second threshold value.
[0004] An automatic control system comprises a delta detector unit and a control unit, the control unit comprising an adjustment unit configured to adjust a signal parameter of an input signal to obtain an output signal depending on a correction signal, a detector unit configured to determine a respective signal parameter of the input signal or the output signal, and a processing unit configured to execute a control algorithm and to determine, by means of the control algorithm and based on a current value of the respective signal parameter of the input signal or the output signal, the correction signal such that the respective signal value of the output signal matches a desired value or falls within a desired range of values.
[0005] A method comprises determining an average value of a signal parameter of an input signal of an automatic control system in a first time interval, determining an average value of the signal parameter of the input signal in a second time interval, determining a difference between the average value of the signal parameter in the first time interval and the average value of the signal parameter in the second time interval, and instructing the automatic control system to adapt at least one parameter of a control algorithm of the automatic control system if the determined difference exceeds a defined first threshold value or falls below a defined second threshold value.
[0006] Other systems, methods, features, and advantages will be, or will become, apparent to one with skill in the art upon examination of the following detailed description and accompanying drawings. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the application, and be protected by the accompanying claims. BRIEF DESCRIPTION OF DRAWINGS
[0007] The arrangement can be better understood with reference to the following description and drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the application. Furthermore, in the drawings, like portions of the drawings are numbered alike.
[0008] Figure 1 An automatic control system of feedback type according to an embodiment of the present disclosure is schematically illustrated.
[0009] Figure 2 An automatic control system of feedforward type according to an embodiment of the present disclosure is schematically illustrated.
[0010] Figure 3 Changes in a parameter of an input signal over time are schematically illustrated.
[0011] Figure 4 The progression of a difference (delta) determined by means of a delta detector unit over time according to an embodiment of the present disclosure is schematically illustrated.
[0012] Figure 5 A method according to an embodiment of the present disclosure is schematically illustrated in a flow chart. DETAILED DESCRIPTION
[0013] Detailed embodiments of the application are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the application. The drawings can not be to scale; some features can be exaggerated or minimised in order to show details that would otherwise be indistinguishible. Accordingly, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to employ the application in a variety of alternative forms.
[0014] It will be appreciated that directional terms, e.g. “upper”, “lower”, “inner”, “outer”, “top”, “bottom” etc. as can be referred to herein merely refer to the orientation of the various components as shown in the drawings. Such terms are provided for context and understanding of the disclosed embodiments.
[0015] Automatic control systems are employed in a variety of applications to control a signal parameter of an input signal. For example, an automatic gain control system can be used to adjust the amplitude of an incoming analog signal in such a way that the resulting output signal has a substantially constant amplitude, regardless of the amplitude of the input signal. That is, an automatic gain control system is a system that is able to maintain the amplitude of an output signal, regardless of variations in the amplitude of an input signal. Another example of an automatic control system is an automatic power control system that maintains the power of an output signal, regardless of variations in the power of an input signal.
[0016] For example, automatic gain control systems are commonly used in radio transceivers to output a signal with a substantially constant volume, regardless of differences in the signal strength of a received radio signal. In the following, the general principles of a difference detector unit and an automatic control system according to embodiments of the present disclosure will be described with respect to an automatic gain control (AGC) system. However, it should be noted that this is merely one example of an automatic control system. In general, any parameter of an input signal can be adjusted to keep a corresponding parameter in an output signal substantially constant. The principles that will be described in the following with respect to an AGC system apply analogously to any other kind of automatic control system. Different types of applications in which automatic control systems can be used include, but are not limited to, for example, automatic valves, optical receivers, similar control systems, digital system applications, and metering pump speed control systems.
[0017] Reference is made to Figure 1 , a feedback type automatic control system is schematically shown. The automatic control system comprises a control unit 100 comprising an adjustment unit 114, a detector unit 110, and a processing unit 112. The adjustment unit 114 is configured to adjust a signal parameter of an input signal IN in dependence on a correction signal COR to obtain an output signal OUT. The detector unit 110 is configured to determine a corresponding signal parameter of the output signal OUT, and the processing unit 112 is configured to execute a control algorithm and, by means of the control algorithm and based on a current value of the corresponding signal parameter of the output signal OUT, to determine the correction signal COR such that the corresponding signal value of the output signal OUT matches a desired value or falls within a desired range of values. The adjustment unit 114 can be or can comprise a multiplier that is configured to, for example, multiply the input signal IN with the correction signal COR.
[0018] Figure 1The automatic control system is a closed loop feedback regulation circuit. For example, the gain of the input signal IN can be dynamically adjusted using the average or peak output signal level. Such automatic gain control systems of the feedback type are commonly used in radio receivers, for example, to equalize the average volume (e.g. loudness) of different radio stations due to differences in received signal strength and variations in the radio signal of a single radio station due to e.g. fading. Without automatic gain control, the sound coming out of the radio receiver would vary greatly from weak to strong signals. If the input signal IN is strong, the automatic gain control system reduces the volume of the input signal IN and when the input signal is weak, it is increased.
[0019] Reference is made to Figure 2 , a schematic illustration of an automatic control system of the feedforward type is shown. The automatic control system comprises a control unit 200 comprising an adjustment unit 214, a detector unit 210 and a processing unit 212. The adjustment unit 214 is configured to adjust a signal parameter of the input signal IN depending on a correction signal COR to obtain an output signal OUT. The detector unit 210 is configured to determine the respective signal parameter of the input signal IN and the processing unit 212 is configured to execute a control algorithm and, by means of the control algorithm and based on the current value of the respective signal parameter of the input signal IN, to determine the correction signal COR such that the respective signal value of the output signal OUT matches a desired value or falls within a desired range of values.
[0020] The main parameters of the control algorithm of the automatic control system are typically the start-up time, the release time and the detection threshold. The start-up time typically defines how long it takes for the automatic control system to start acting (i.e. start adjusting the respective parameter of the input signal IN) after the respective parameter is detected to be above a defined threshold. The release time defines how long it takes for the automatic control system to return to its normal state after the respective parameter is detected to be below a defined threshold. The detection threshold typically defines the minimum deviation from the desired value for the automatic control system to start acting. Further parameters of the control algorithm include, but are not limited to, the release hysteresis (the amount by which the signal level has to decrease beyond the target level to force the automatic gain control to increase the gain and start the release) and the start-up hysteresis (the amount by which the signal level has to increase beyond the target level to force the automatic gain control to decrease the gain and start the start-up).
[0021] In many applications, the automatic gain control system is designed such that the level of the respective signal parameter is not changed abruptly (too fast) so that no audible artifacts are generated. In other words, the automatic gain control system usually changes the level of a given parameter (e.g. the volume) to achieve a defined target level such that after a certain time, the level remains constant statistically. However, if the automatic gain control system reacts not fast enough to changes of the input signal IN, the audio level can not be adapted synchronously. For example, the volume of a first song can be increased and when a second song is played immediately afterwards, the first part of the second song can be played with a very high volume until the volume of the second song has been adjusted to the target volume. One approach to overcome this problem is to tune the control algorithm to always have an extremely high reactivity. However, this can lead to a highly unpleasant output signal OUT with excessive compression. Further, the artistic intent of the input signal can even be reduced. This can result in a highly unpleasant listening experience. A further constraint is that the automatic control system is usually expected to be used in real-time domain. This requires to keep the look-ahead buffer at a minimum size which only allows to analyze a very short portion of the input signal IN or the output signal OUT. Thus, due to normal latency constraints, the automatic control system can operate without gathering information from the whole signal.
[0022] The automatic control system according to the embodiments disclosed herein allows to dynamically adapt their behavior from a slow “settling” leveling to a faster and more “reactive” leveling based on the level of the input signal. In addition to the control units 100, 200 described above with respect to Figure 1 and Figure 2 In addition to the control units 100, 200 described above with respect to
[0023] With reference to Figure 3The difference between the average of the signal values in the first time interval t0-t1 and the average of the signal values in the second time interval t1-t2 is indicated as Δ1. The difference Δ1 (positive difference) is relatively small and can be below a defined threshold. Therefore, no adjustment of the control algorithm parameters is initiated. The difference between the average of the signal values in the second time interval t1-t2 and the average of the signal values in the third time interval t2-t3 is indicated as Δ2. This difference Δ2 (negative difference) is relatively large and can fall below a defined threshold. Therefore, an adjustment of the control algorithm parameters can be initiated. The same applies to the difference Δ3 (positive difference) between the average of the signal values in the third time interval t2-t3 and the average of the signal values in the fourth time interval t3-t4, which is relatively large such that it exceeds a defined threshold. In the example shown in Figure 3 the difference Δ4 (negative difference) between the average of the signal values in the fourth time interval t3-t4 and the average of the signal values in the fifth time interval t4-t5 is again relatively small and therefore between a defined threshold. For example, therefore, the control algorithm can return to its standard settings.
[0024] In the example of Figure 3 the different time intervals t0-t1, t1-t2, t2-t3, t3-t4 and t4-t5 have equal lengths. However, this is merely an example. The different time intervals t0-t1, t1-t2, t2-t3, t3-t4 and t4-t5 can generally have different lengths. That is, the average of the signal values in a first length of time interval can be compared to the average of the signal values in a second length of time interval, wherein the second length is shorter or longer than the first length. Since the automatic control system generally needs to adjust the signal values of the input signal IN in real time, the time intervals t0-t1, t1-t2, t2-t3, t3-t4 and t4-t5 can be relatively short. For example, according to one example, the time intervals can be between 1 ms (millisecond) and 50 ms. Longer or shorter time intervals are generally also possible. However, relatively short time intervals can increase the reactivity and accuracy of the automatic control system.
[0025] Figure 3The time intervals t0-t1, t1-t2, t2-t3, t3-t4 and t4-t5 in the above equation are directly consecutive time intervals. That is, in this example, the difference between the average of the signal parameter in the first time interval and the average of the signal parameter in the directly preceding second time interval is determined. However, this is merely an example. The two relevant time intervals do not necessarily have to be directly consecutive time intervals. There can typically be some time interval between the first time interval and the second time interval. According to a further example, the second time interval can even partially overlap with the first time interval. The automatic control system thus typically needs to adjust to the signal value of the input signal IN in real time, and the time interval between the two respective time intervals can thus be relatively short.
[0026] According to an example, the automatic control system has defined standard reaction times (start-up times / release times) defining how quickly the system reacts to a change in the signal parameter. For example, the standard start-up time can be set to a first value (e.g. 25 ms) and the standard release time can be set to a second value (e.g. 100 ms). These first and second values of the start-up time and the release time are used whenever the difference Δ between the average of the signal value in the first time interval and the average of the signal value in the second time interval is smaller than a first defined threshold value (e.g. a positive threshold value) and larger than a second defined threshold value (e.g. a negative threshold value). For example, the start-up time and the release time can be reduced when it is detected that the difference Δ between the average of the signal value in the first time interval and the average of the signal value in the second time interval exceeds the first defined threshold value or falls below the second defined threshold value. According to an example, the standard start-up time of 25 ms can be set to a value between 10 ms and 20 ms when Δ is larger than the first defined threshold value or smaller than the second defined threshold value, and the standard release time of 100 ms can be set to a value between 50 ms and 90 ms when Δ is larger than the first defined threshold value and smaller than the second defined threshold value. That is, according to an example, the larger the difference Δ between the average of the signal value of the two time intervals, the shorter the start-up time and the release time. In this way, the start-up time and the release time are dynamically adjusted.
[0027] According to one example, at least one parameter of the control algorithm (e.g. the start time and / or the release time) is adapted in proportion to the determined difference Δ when it is detected that the difference Δ between the average of the signal values in the first time interval and the average of the signal values in the second time interval exceeds a first defined threshold value or falls below a second defined threshold value. In some examples, even more than two threshold values can be considered. For example, if the difference Δ between the average of the signal values in the first time interval and the average of the signal values in the second time interval exceeds a third defined threshold value which is larger than the first defined threshold value or falls below a fourth defined threshold value which is lower than the second defined threshold value, at least one parameter of the control algorithm (e.g. the start time and / or the release time) can be set to a defined maximum or minimum value. The defined maximum or minimum value can be the value which deviates most from the standard value. For example, if the at least one parameter of the control algorithm is the start time, the start time can be set to its fastest possible value in case the difference Δ exceeds the third defined threshold value or falls below the fourth defined threshold value.
[0028] This is exemplarily shown in Figure 4 Fig. 1. Figure 4 The determined difference Δ is schematically shown over time. Until the time point ti, the difference Δ is below the first defined threshold value (lower positive threshold value) and greater than the second defined threshold value (higher negative threshold value). Accordingly, the respective parameter of the control algorithm (e.g. the start time) is set to the defined value. When the difference Δ exceeds the first defined threshold value at the time point ti (positive difference if the average in the first time interval is greater than the average in the second time interval), the parameter of the control algorithm is adjusted (e.g. the start time is reduced). At the time point t2, the difference Δ falls again below the first defined threshold value. Accordingly, the parameter of the control algorithm can return to its standard value. However, in the example of Figure 4 a hysteresis of the difference is considered to avoid too many changes of the parameter of the control algorithm in too short time ranges. That is, the system waits until the time point t3 and only resets the parameter of the control algorithm to its standard value once a defined time interval (hysteresis of the difference) has passed. The difference Δ between the time points t2 and t4 is below the first defined threshold value (lower positive threshold value) and greater than the second defined threshold value (higher negative threshold value) so that no adjustment of the parameter of the control algorithm is initiated. At the time point t4, the difference Δ falls below the second defined threshold value (negative difference if the average in the first time interval is lower than the average in the second time interval). Accordingly, the parameter of the control algorithm will be adjusted again.
[0029] When the difference Δ exceeds the second defined threshold value again at the time point t5 and returns to being below the first defined threshold value at the time point t6, the parameter of the control algorithm is adjusted again. Figure 4the difference Δ exceeds the first defined threshold value again between the time points t6 and t7, this applies as well.
[0030] According to one example, the parameter of the control algorithm is adapted in proportion to the determined difference Δ when the difference Δ is between the first defined threshold value and the third defined threshold value or between the second defined threshold value and the fourth defined threshold value. That is, the larger the difference Δ, the larger the change of the parameter of the control algorithm. Returning to the example presented above, for a difference Δ between the lower positive threshold value and the higher positive threshold value, the start-up time can be adapted in proportion to the determined difference Δ, as indicated in Figure 4 For example, for a difference Δ exceeding the even higher positive threshold value, the start-up time can be set to its fastest possible value (e.g. 10 ms). This can apply as well for a difference Δ between the higher negative threshold value and the lower negative threshold value (e.g. the start-up time is adapted in proportion to the determined difference Δ) and a difference below the lower negative threshold value (e.g. the start-up time is set to its fastest possible value).
[0031] Figure 4 The differential hysteresis time (the time period until another adjustment can be performed after an adjustment of the control algorithm parameter) as indicated in the above can be set to any suitable value. This can typically depend on the kind of application in which the automatic control system is used and the control algorithm used in the automatic control system. Changing the start-up time and / or the release time after detecting that the difference Δ exceeds or falls below a defined threshold value is only one of several examples. In general, any parameter of the control algorithm can be adjusted. In general, the automatic control system can be implemented in many different ways and different control algorithms can be used. Irrespective of the specific implementation of the control unit 100, 200 and the control algorithm used by the processing unit 112, 212, the principles of the automatic control system described herein apply as well.
[0032] The delta detector unit 120 as described above can be part of the automatic control system. That is, the delta detector unit 120 can be integrated into the automatic control system. However, the delta detector unit 120 can typically be a separate component which is suitably connected to the automatic control system. The delta detector unit 120 according to embodiments of the present disclosure is configured to determine an average value of a signal parameter of an input signal IN of the automatic control system over a first time interval, to determine an average value of the signal parameter of the input signal IN over a second time interval, to determine a difference Δ between the average value of the signal parameter over the first time interval and the average value of the signal parameter over the second time interval, and to indicate the automatic control system to adapt at least one parameter of a control algorithm of the automatic control system if the determined difference Δ exceeds a defined first threshold value or falls below a defined second threshold value.
[0033] The signal parameter of the input signal IN can be determined in any suitable manner by means of suitable sensors and / or circuits, for example. The kind of sensors or circuits for performing such measurements typically depends on the kind of parameter to be determined. However, sensors and circuits for measuring any kind of signal parameter are typically known. The average value of a parameter over a defined time interval can also typically be determined with known circuits and systems. The comparison of the two average values of the two time intervals can be performed by means of a comparator, for example.
[0034] Figure 5 The corresponding method according to embodiments of the present disclosure is exemplarily illustrated in Fig. 5 and comprises determining an average value of a signal parameter of an input signal IN of the automatic control system over a first time interval (step 502), determining an average value of the signal parameter of the input signal IN over a second time interval (step 504), determining a difference Δ between the average value of the signal parameter over the first time interval and the average value of the signal parameter over the second time interval (506), and indicating the automatic control system to adapt at least one parameter of a control algorithm of the automatic control system if the determined difference Δ exceeds a defined first threshold value or falls below a defined second threshold value (determined in step 508) (step 510).
[0035] The description of the embodiments has been presented for purposes of illustration and description. Suitable modifications and variations to the embodiments can be performed in light of the above description or can be obtained from practicing the methods. The described arrangements are to be considered in all respects as illustrative and not restrictive, and all modifications and alterations that come within the scope and spirit of the arrangements are desired to be protected. As used in this application, the terms “one,” “a,” or “an” mean “one or more” unless expressly specified otherwise. Further, the reference to “one embodiment” or “an embodiment” of the present disclosure is not a reference to the same embodiment; nor is it intended to exclude other embodiments that also incorporate one or more of the recited features. The terms “first,” “second,” and “third” and the like, do not denote any ordinal, numerical or hierarchical significance, but are used merely to distinguish the entities so designated. The described systems are to be considered in all respects as illustrative and not restrictive, and all modifications and alterations that come within the scope and spirit of the systems are desired to be protected. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems and configurations described and other features, functions, and / or properties disclosed herein. The claims, particularly, are to be construed in accordance with the principles of patent law that govern the granting of patents, such as 35 U.S.C. §§ 101, 102, 103, and 112.
Claims
1. A differential detector unit (120), the differential detector unit (120) being configured to: Determine the average value of the signal parameters of the input signal (IN) of the automatic control system during the first time interval. Determine the average value of the signal parameters of the input signal (IN) during the second time interval. Determine the difference (Δ) between the average value of the signal parameters during the first time interval and the average value of the signal parameters during the second time interval, and If the determined difference (Δ) exceeds a defined first threshold or falls below a defined second threshold, the automatic control system is instructed to adjust at least one parameter of the control algorithm of the automatic control system.
2. The differential detector unit (120) as described in claim 1, wherein, If the determined difference (Δ) exceeds a defined first threshold or falls below a defined second threshold, the difference detector unit (120) is configured to instruct the automatic control system to adjust at least one parameter of its control algorithm proportionally to the determined difference (Δ).
3. The differential detector unit (120) as described in claim 2, wherein, If the determined difference (Δ) exceeds a defined third threshold greater than the defined first threshold or falls below a defined fourth threshold lower than the defined second threshold, the difference detector unit (120) is configured to instruct the automatic control system to adjust at least one parameter of its control algorithm to a defined maximum or minimum value.
4. The differential detector unit (120) as described in any one of claims 1 to 3, wherein, If the determined difference (Δ) exceeds a defined first threshold or falls below a defined second threshold, the difference detector unit (120) is configured to instruct the automatic control system to adjust at least one of the start time and release time of its control algorithm.
5. The differential detector unit (120) as claimed in any one of claims 1 to 4, wherein the signal parameter of the input signal (IN) is the amplitude of the input signal (IN).
6. An automatic control system, comprising: The differential detector unit (120) as described in claim 1; and A control unit (100, 200) includes: an adjustment unit (114, 214) configured to adjust the signal parameters of the input signal (IN) depending on a correction signal (COR) to obtain an output signal (OUT); a detector unit (110, 210) configured to determine the corresponding signal parameters of the input signal (IN) or the output signal (OUT); and a processing unit (112, 212) configured to execute a control algorithm and, by means of the control algorithm and based on the current values of the corresponding signal parameters of the input signal (IN) or the output signal (OUT), determine the correction signal (COR) such that the corresponding signal value of the output signal (OUT) matches a desired value or falls within a desired value range.
7. The automatic control system as described in claim 6, wherein... If it is determined that the difference (Δ) lies between the defined first threshold and the defined second threshold, then the processing units (112, 212) are configured to set at least one parameter of the control algorithm to a first standard value, and If the determined difference (Δ) exceeds the defined first threshold or falls below the defined second threshold, the processing unit (112, 212) is configured to set at least one parameter of the control algorithm to a second value that is different from the first value.
8. The automatic control system of claim 6 or 7, wherein the at least one parameter of the control algorithm adjusted by the processing unit (112, 212) is at least one of start-up time and release time.
9. The automatic control system as described in claim 8, wherein... If the determined difference (Δ) exceeds the defined first threshold or falls below the defined second threshold, the processing unit (112, 212) is configured to reduce the start time and / or release time of the control algorithm.
10. The automatic control system according to any one of claims 6 to 9, wherein the automatic control system is an automatic gain control (AGC) system, and the signal parameter of the input signal (IN) adjusted by means of the adjustment unit (114, 214) is the amplitude of the input signal (IN).
11. The automatic control system of any one of claims 6 to 10, wherein the processing unit (112, 212) is configured to allow a defined differential lag time to pass after at least one parameter of the control algorithm has been adjusted, and before the at least one parameter of the control algorithm has been reset or readjusted.
12. A method comprising: Determine the average value of the signal parameters of the input signal (IN) of the automatic control system during the first time interval. Determine the average value of the signal parameters of the input signal (IN) during the second time interval. Determine the difference (Δ) between the average value of the signal parameters during the first time interval and the average value of the signal parameters during the second time interval, and If the determined difference (Δ) exceeds a defined first threshold or falls below a defined second threshold, the automatic control system is instructed to adjust at least one parameter of the control algorithm of the automatic control system.