Signal testing device

Abstract

The embodiment of the invention belongs to the electronic technology, and provides a signal testing device. The signal test device comprises a test parameter value extraction module and a result indication module, and the test parameter value extraction module is connected with the result indication module. The test parameter value extraction module is used for receiving a PWM signal which is output by the to-be-tested control device and is used for representing a target instruction, and extracting a value of a target test parameter of the PWM signal; the result indication module is used for displaying a test result corresponding to the value of the target test parameter; the test result is used for representing whether the value of the target test parameter is a target value. According to the invention, the PWM test efficiency can be improved.

Description

Technical Field

[0001] Embodiments of the present application relate to electronic technology. More specifically, it relates to a signal testing device. Background Art

[0002] During the operation of a household electrical appliance (such as a refrigerator), a control device of the household electrical appliance can control the operation of other components of the household electrical appliance (such as a blower, a compressor, or a vacuum pump, etc.) through a PWM signal. Generally, different operating states of the above components correspond to different PWM duty cycles and / or PWM effective values. Therefore, it is crucial to detect the accuracy of different PWM duty cycles and / or PWM effective values output by the control device.

[0003] Currently, existing PWM testing methods all require first capturing the waveform of the PWM signal through a testing device, and then manually analyzing the captured waveform to analyze and determine whether the PWM duty cycle and / or PWM effective value, etc. are accurate. Therefore, existing PWM testing methods have the problem of low efficiency. Summary of the Invention

[0004] An exemplary embodiment of the present application provides a signal testing device, which can improve the efficiency of PWM testing.

[0005] In a first aspect, the present application provides a signal testing device, the signal testing device includes: a test parameter value extraction module, and a result indication module, the test parameter value extraction module is connected to the result indication module;

[0006] The test parameter value extraction module is configured to receive a PWM signal for characterizing a target instruction output by a control device to be tested, and extract the value of a target test parameter of the PWM signal;

[0007] The result indication module is configured to display a test result corresponding to the value of the target test parameter; the test result is used to characterize whether the value of the target test parameter is a target value.

[0008] In some embodiments, the result indication module includes a plurality of indication units, and the indication unit includes: an indicator light;

[0009] The result indication module is configured to control the indicator light of at least one indication unit corresponding to the value of the target test parameter to light up according to the value of the target test parameter; when the indicator lights of different numbers of the indication units light up, the characterized target values are different.

[0010] In some embodiments, the indication unit further includes: a voltage stabilizing sub-unit, and the test parameter value extraction module is connected to the indicator light through the voltage stabilizing sub-unit;

[0011] When the value of the target test parameter reaches the breakdown conduction condition of the voltage stabilizing subunit, the voltage stabilizing subunit conducts, so that the indicator light connected to the voltage stabilizing subunit lights up.

[0012] In some embodiments, the target test parameter is the effective value of the PWM signal; the test parameter value extraction module includes: a first buffer unit and a sampling unit, and the first buffer unit is connected to the result indication module through the sampling unit;

[0013] The first buffer unit is configured to receive the PWM signal for characterizing the target instruction output by the device under test, and isolate the impedance between the PWM signal output circuit of the device under test and the sampling unit;

[0014] The sampling unit is configured to extract the effective value of the PWM signal.

[0015] In some embodiments, the sampling unit includes: a first resistor and a first capacitor. The first end of the first resistor is connected to the first buffer unit, the second end of the first resistor is connected to the first end of the first capacitor and the result indication module, and the second end of the first capacitor is grounded;

[0016] The PWM signal charges the first capacitor through the first resistor, and the voltage on the first capacitor is used to characterize the effective value of the PWM signal.

[0017] In some embodiments, the test parameter value extraction module further includes: a second buffer unit, and the sampling unit is connected to the result indication module through the second buffer unit;

[0018] The second buffer unit is configured to isolate the impedance between the sampling unit and the result indication module.

[0019] In some embodiments, the target test parameter is the duty cycle of the PWM signal; the test parameter value extraction module includes: an effective value acquisition unit and a division unit, and the effective value acquisition unit is connected to the result indication module through the division unit;

[0020] The effective value acquisition unit is configured to receive the PWM signal for characterizing the target instruction output by the device under test and extract the effective value of the PWM signal;

[0021] The division unit is configured to divide the effective value of the PWM signal by the amplitude of the PWM signal to obtain the duty cycle of the PWM signal.

[0022] In some embodiments, the effective value acquisition unit includes: a charging sub-unit and a discharging sub-unit, the charging sub-unit is connected to the discharging sub-unit; the discharging sub-unit is connected to the result indication module through the division unit;

[0023] The charging sub-unit is configured to receive the PWM signal and charge through the PWM signal, so that the voltage on the charging sub-unit is used to represent the effective value of the PWM signal;

[0024] The discharging sub-unit is configured to discharge when the amplitude of the PWM signal is zero.

[0025] In some embodiments, the discharging sub-unit includes: a buffer and a discharging resistor, the charging sub-unit is connected to one end of the discharging resistor and one end of the division unit through the buffer, and the other end of the discharging resistor is grounded;

[0026] The buffer is configured to isolate the impedance between the charging sub-unit and the discharging resistor; the discharging sub-unit discharges through the discharging resistor.

[0027] In some embodiments, the target test parameter is the duty cycle of the PWM signal; the test parameter value extraction module includes: an effective value acquisition unit, a division unit, and a comparison unit, the effective value acquisition unit is connected to the comparison unit through the division unit, and the comparison unit is connected to the result indication module;

[0028] The effective value acquisition unit is configured to receive the PWM signal for representing the target instruction output by the device under test to be controlled, and extract the effective value of the PWM signal;

[0029] The division unit is configured to divide the effective value of the PWM signal by the amplitude of the PWM signal to obtain the duty cycle of the PWM signal;

[0030] The comparison unit includes at least one comparison sub-unit, and each comparison sub-unit is connected to one indication unit; different comparison sub-units corresponding to different duty cycles of the PWM signal output the first level; when the comparison sub-units outputting the first level are different, the number of lit indicator lights is different.

[0031] The signal testing device provided by this application can extract the values of target test parameters of the PWM signal used to represent the target instruction output by the control device to be tested through the above-mentioned test parameter value extraction module. Furthermore, the result indication module can display the test result indicating whether the value of the target test parameter corresponding to the value of the target test parameter is the target value. Through the above signal testing device, the test result for the PWM signal can be directly displayed, eliminating the need for manual analysis of the PWM waveform to determine whether the PWM signal output by the control device to be tested is accurate, thereby improving the efficiency of PWM testing. Description of the Drawings

[0032] To more clearly illustrate the embodiments of this application or the implementation manners in the related art, the following will briefly introduce the drawings required for use in the description of the embodiments or the related art. Obviously, the drawings in the following description are some embodiments of this application, and those of ordinary skill in the art can also obtain other drawings based on these drawings.

[0033] Figure 1 Structural schematic diagram of a signal testing device provided by this application;

[0034] Figure 2 Structural schematic diagram of another signal testing device provided by this application;

[0035] Figure 3 Structural schematic diagram of yet another signal testing device provided by this application;

[0036] Figure 4 Structural schematic diagram of yet another signal testing device provided by this application;

[0037] Figure 5 Structural schematic diagram of a sampling unit provided by this application;

[0038] Figure 6 Structural schematic diagram of another test parameter value extraction module provided by this application;

[0039] Figure 7 Structural schematic diagram of yet another signal testing device provided by this application;

[0040] Figure 8 Structural schematic diagram of yet another signal testing device provided by this application;

[0041] Figure 9 Structural schematic diagram of yet another test parameter value extraction module provided by this application;

[0042] Figure 10 Structural schematic diagram of an electron emission unit provided by this application;

[0043] Figure 11 A structural schematic diagram of another signal testing device provided by this application;

[0044] Figure 12 A structural schematic diagram of another signal testing device provided by this application;

[0045] Figure 13 A structural schematic diagram of another signal testing device provided by this application. Specific embodiments

[0046] To make the objectives, embodiments, and advantages of this application clearer, the following will clearly and completely describe the exemplary embodiments of this application with reference to the accompanying drawings in the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only a part of the embodiments of this application, rather than all of the embodiments.

[0047] It should be noted that the brief description of the terms in this application is only for facilitating the understanding of the following described embodiments, rather than intending to limit the embodiments of this application. Unless otherwise specified, these terms should be understood in their ordinary and general meanings.

[0048] In addition, the terms "include" and "have" and any variations thereof are intended to cover but not exclude inclusion. For example, a product or device including a series of components does not necessarily have to be limited to those clearly listed components, but may include other components not clearly listed or inherent to these products or devices.

[0049] During the operation of a household electrical appliance (such as a refrigerator), the control device of the household electrical appliance can control the operation of other components of the household electrical appliance (such as a fan, a compressor, or a vacuum pump, etc.) by outputting a Pulse Width Modulation (PWM) signal. For example, the control device can control the rotation speed of the fan, the rotation speed of the compressor, etc. by different PWM signals. That is to say, the operation of the household electrical appliance involves the output of the PWM signal.

[0050] Generally, the operating states of the above different loads have fixed PWM duty cycles and / or PWM effective values to control different operating states, such as different rotation speeds, etc. Therefore, before the control device is installed in an electronic device, it is necessary to detect different PWM duty cycles and / or PWM effective values output by the control device to ensure the correctness and stability of the performance of the PWM signal output by the control device.

[0051] Currently, the existing common PWM test methods mainly have the following two ways: The first is to use online debugging software to capture and observe the PWM signal waveform. The second is to use an oscilloscope to extract the PWM signal and observe the PWM signal waveform. That is to say, the existing PWM test methods all need to first capture the waveform of the PWM signal through a test device, and then manual analysis of the captured waveform is required to determine whether the PWM duty cycle and / or the PWM effective value are accurate. Therefore, the existing PWM test methods have the problem of low efficiency.

[0052] Considering the above problems existing in the existing PWM test methods, therefore, this application proposes a PWM test device that can directly indicate whether the PWM signal is accurate. Through this device, manual analysis of the PWM waveform is not required, thus improving the efficiency of PWM testing.

[0053] The technical solution of this application will be described in detail below in combination with specific embodiments. These specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0054] Figure 1 It is a schematic structural diagram of a signal test device provided by this application. As Figure 1 shown, the signal test device may include: a test parameter value extraction module, and a result indication module. Among them, the test parameter value extraction module can be connected to the result indication module.

[0055] The test parameter value extraction module can be used to receive the PWM signal for characterizing the target instruction output by the control device to be tested, and extract the value of the target test parameter of the PWM signal.

[0056] Optionally, the above control device to be tested can be any control device that can output a PWM signal, and this application does not limit this. For example, the control device to be tested can be the main control board of a refrigerator, or the main control microcontroller unit (MCU) of a refrigerator, etc.

[0057] It should be understood that this application does not limit the above target instruction either. For example, the target instruction can be used to indicate adjusting the speed of a fan, temperature control, etc. It should be understood that this application does not limit how the above control device to be tested outputs the above PWM signal. For example, the control device to be tested can respond to an operation that triggers the output of the above target instruction and output the above PWM signal.

[0058] Optionally, the above target test parameter can be any parameter of the PWM that can be used to characterize the instruction of the PWM signal, such as any one of the duty cycle, effective value, frequency, etc. of the PWM.

[0059] The result indicating module can be used to display the test result corresponding to the value of the above-mentioned target test parameter. Among them, the test result can be used to characterize whether the value of the above-mentioned target test parameter is the target value.

[0060] Optionally, the above-mentioned target value may refer to the target value corresponding to the PWM signal when characterizing the above-mentioned target instruction.

[0061] Exemplarily, taking the case where a logic program is pre-deployed in the result indicating module as an example, the result indicating module can compare the value of the target test parameter with the target value through the logic program and output the test result indicating whether the value of the target test parameter is the same as the target value.

[0062] Or, taking the above-mentioned result indicating module including multiple indicator lights as an example, the number of lit indicator lights corresponding to different values of the target test parameter may be different. That is to say, the result indicating module can light up the number of indicator lights corresponding to the value of the target test parameter so that the user can determine whether the value of the target test parameter is the target value according to the number of lit indicator lights.

[0063] For example, assuming that the number of lit indicator lights corresponding to the target value of the PWM signal used to characterize the target instruction output by the above-mentioned control device to be tested triggered by the user is 2, if the number of lit indicator lights of the result indicating module is not 2 (for example, 3 or 1, etc.) when tested by the signal testing device, it means that the value of the target test parameter is not the target value, so it can be explained that the PWM signal output by the control device to be tested is inaccurate. If the number of lit indicator lights of the result indicating module is 2 when tested by the signal testing device, it means that the value of the target test parameter is the target value, so it can be explained that the PWM signal output by the control device to be tested is accurate.

[0064] In this embodiment, the value of the target test parameter of the PWM signal used to characterize the target instruction output by the control device to be tested can be extracted through the above-mentioned test parameter value extraction module, and then the result indicating module can display the test result used to characterize whether the value of the target test parameter is the target value corresponding to the value of the target test parameter. Through the above-mentioned signal testing device, the test result for the PWM signal can be directly displayed, without the need for manual analysis of the PWM waveform to determine whether the PWM signal output by the control device to be tested is accurate, improving the efficiency of PWM testing.

[0065] The structure of the above-mentioned result indicating module will be described in detail below:

[0066] Figure 2 It is a schematic structural diagram of another signal testing device provided by the present application. As Figure 2As shown, as a possible implementation, the result indication module may include a plurality of indication units. It should be understood that Figure 2 taking the three indication units included in the result indication module as an example, an exemplary description is made of the number of indication units included in the result indication module. The present application does not limit the number of indication units included in the result indication module. The above test parameter value extraction module may be connected to the indicator light.

[0067] As Figure 2 shown, the above indication unit may include: an indicator light. It should be understood that the present application does not limit the type of the indicator light either. For example, the indicator light may be a light-emitting diode (LED) lamp.

[0068] The above result indication module can be used to control the indicator lights of at least one indication unit corresponding to the value of the target test parameter to light up according to the value of the target test parameter. Among them, when the indicator lights of different numbers of indication units are lit, the represented target values are different.

[0069] In some embodiments, the result indication module may, for example, include a storage unit and a processing unit. The storage unit may store a mapping relationship between the value of the target test parameter and the number of indicator lights to be lit. The processing unit may determine the number of indicator lights to be lit according to the mapping relationship and the value of the target test parameter, and control the corresponding number of indicator lights to light up.

[0070] Figure 3 is a schematic structural diagram of another signal testing device provided by the present application. As Figure 3 shown, in some embodiments, the indication unit may further include: a voltage stabilizing sub-unit. The above test parameter value extraction module may be connected to the indicator light through the voltage stabilizing sub-unit.

[0071] Exemplarily, the above voltage stabilizing sub-unit may be a device such as a voltage stabilizing diode, and the present application does not limit the type of the voltage stabilizing sub-unit.

[0072] When the value of the above target test parameter reaches the breakdown conduction condition of the voltage stabilizing sub-unit, the voltage stabilizing sub-unit may conduct, so that the indicator light connected to the voltage stabilizing sub-unit lights up.

[0073] Taking the value of the above-mentioned target test parameter as the effective value of the PWM signal as an example, exemplarily, if the PWM effective value is 3.3V, the voltage stabilizing sub-unit 1 breaks down and conducts, and the indicator light 1 lights up, indicating that the current PWM effective value is 3.3V. If the PWM effective value is 5V, the voltage stabilizing sub-unit 1 and the voltage stabilizing sub-unit 2 break down and conduct, and the indicator light 1 and the indicator light 2 light up, indicating that the current PWM effective value is 5V. If the PWM effective value is 9V, the voltage stabilizing sub-unit 1, the voltage stabilizing sub-unit 2, and the voltage stabilizing sub-unit 3 break down and conduct, and the indicator light 1, the indicator light 2, and the indicator light 3 light up, indicating that the current PWM effective value is 9V.

[0074] In this embodiment, the result indicating module can visually display the value of the target test parameter of the PWM signal by lighting different numbers of indicator lights, so that the user can directly determine the accuracy of the PWM signal output by the control device to be tested according to the number of lit indicator lights, improving the test efficiency of the PWM signal.

[0075] Taking the effective value of the PWM signal as the target test parameter as an example, Figure 4 is a schematic structural diagram of another signal testing device provided by the present application. As Figure 4 shown, as a possible implementation manner, the test parameter value extraction module may include: a first buffer unit, and a sampling unit. Among them, the first buffer unit can be connected to the result indicating module through the sampling unit.

[0076] The above-mentioned first buffer unit can be used to receive the PWM signal for characterizing the target instruction output by the control device to be tested, and isolate the impedance between the "PWM signal output circuit" of the control device to be tested and the sampling unit.

[0077] Exemplarily, the above-mentioned first buffer unit may include components such as a buffer that can perform impedance isolation.

[0078] The above-mentioned sampling unit can be used to extract the effective value of the PWM signal. Exemplarily, the above-mentioned sampling unit may include rechargeable components such as a capacitor, so that the sampling unit can extract the effective value of the PWM signal through the rechargeable components such as the capacitor. Taking the sampling unit including a capacitor as an example, the sampling unit charges the capacitor so that the voltage on the capacitor can be used to characterize the effective value of the above-mentioned PWM signal.

[0079] By impedance-isolating the "PWM signal output circuit" of the control device to be tested from the sampling unit, it is possible to avoid the PWM signal being pulled down due to impedance reasons, thereby improving the accuracy of the PWM signal output to the subsequent sampling unit. Therefore, the accuracy of the sampling unit in extracting the effective value of the PWM signal can be improved. Thus, through this signal testing device, not only can the efficiency of the PWM signal test be improved, but also the accuracy of the PWM signal test can be enhanced.

[0080] Figure 5 This is a schematic structural diagram of a sampling unit provided by the present application. As Figure 5 shown, in some embodiments, the sampling unit may include: a first resistor and a first capacitor. Wherein, the first end of the first resistor may be connected to the first buffer unit described above. The second end of the first resistor may be connected to the first end of the first capacitor and the result indication module described above. The second end of the first capacitor may be grounded.

[0081] Based on the above sampling unit, the PWM signal charges the first capacitor through the first resistor. The voltage on the first capacitor can be used to represent the effective value of the PWM signal.

[0082] It should be understood that the present application does not limit the resistance value of the first resistor, the capacitance value of the first capacitor, etc.

[0083] Through the above sampling unit, the extraction of the effective value of the PWM signal is realized, laying a foundation for subsequently displaying the test result based on the effective value of the PWM signal.

[0084] Figure 6 This is a schematic structural diagram of another test parameter value extraction module provided by the present application. As Figure 6 shown, in some embodiments, the test parameter value extraction module may further include: a second buffer unit. Wherein, the sampling unit may be connected to the result indication module through the second buffer unit.

[0085] The second buffer unit described above can be used to impedance-isolate the sampling unit from the result indication module. By impedance-isolating the sampling unit from the result indication module, it is possible to avoid the effective value of the PWM signal being pulled down due to impedance reasons, thereby improving the accuracy of the effective value detection of the PWM signal.

[0086] Exemplarily, the second buffer unit described above may include components such as a buffer that can perform impedance isolation.

[0087] Exemplarily, still taking the aforementioned target test parameter as the effective value of the PWM signal and the number of indicator lights as N as an example, Figure 7 This is a schematic structural diagram of another signal testing device provided by the present application. AsFigure 7 As shown, where the main control MCU can be, for example, the main control MCU of a refrigerator. This main control MCU can be used as the aforementioned control device to be tested. The above first buffer unit can include, for example, Figure 7 the buffer for receiving the PWM signal as shown. The sampling unit can be an effective value extraction module, and the above second buffer unit can be the buffer connected to the indicator light.

[0088] Based on the signal testing device as Figure 7 shown, taking this signal testing device which can also be called a test fixture as an example, Figure 8 is a schematic structural diagram of another signal testing device provided by this application. As Figure 8 shown, among them, the resistor R1, the capacitor C2, and the buffer (i.e., operational amplifier) U1 constitute the first buffer unit. The resistor R3, the capacitor C3, and the buffer U2 can constitute the second buffer unit. The resistor R2 and the capacitor C1 can constitute the above sampling unit. ZD1, ZD2, and ZD3 are all voltage stabilizing diodes. LED1, LED2, and LED3 are indicator lights.

[0089] During the function self-check process of the electronic control board, the main control MCU periodically outputs corresponding PWM cyclically, and the effective value is the value required for the speed regulation of the corresponding load of the refrigerator, such as 3.3V, 5V, 9V, etc.

[0090] The PWM signal passes through the buffer composed of U1, R1, and C2 to perform effective impedance isolation with the PWM output circuit, avoiding the PWM signal being pulled down due to impedance reasons. The PWM signal passing through the buffer charges C1 through R2, and finally the voltage on C1 is the effective value of the PWM.

[0091] The effective value of the PWM passes through the buffer composed of U2, R3, and C3 to perform effective impedance isolation with loads such as LED1, avoiding the effective value of the PWM being pulled down due to impedance reasons. If the effective value of the PWM is 3.3V, the voltage stabilizing diode ZD1 breaks down and conducts, and LED1 lights up, indicating that the current effective value of the PWM is 3.3V. If the effective value of the PWM is 5V, the voltage stabilizing diodes ZD1 and ZD2 break down and conduct, and LED1 and LED2 light up, indicating that the current effective value of the PWM is 5V. If the effective value of the PWM is 9V, the voltage stabilizing diodes ZD1, ZD2, and ZD3 break down and conduct, and LED1, LED2, and LED3 light up, indicating that the current effective value of the PWM is 9V. When the effective value of the PWM is other values, and so on.

[0092] In this embodiment, only several components are needed to complete the determination of the effective values of several known PWMs. There is no need for software participation, and the cumbersome work of using an oscilloscope at the test site is also avoided. It can be visually confirmed, improving the efficiency of PWM effective value detection. By visually detecting and judging the effective value of the PWM output by the main control MCU at a certain moment, it more effectively saves the time required for the detection of the performance of the electronic control board circuit and avoids the necessity of building tooling equipment and the inconvenience brought by using an oscilloscope at the test site, further improving the efficiency of PWM effective value detection.

[0093] Taking the duty cycle of the PWM signal as an example of the target test parameter, Figure 9 is a schematic structural diagram of another test parameter value extraction module provided by the present application. As Figure 9 shown, as a possible implementation manner, the test parameter value extraction module may include: an effective value acquisition unit, and a division unit. Among them, the effective value acquisition unit is connected to the result indication module through the division unit.

[0094] The effective value acquisition unit can be used to receive the PWM signal representing the target instruction output by the to-be-tested control device described above, and extract the effective value of the PWM signal.

[0095] The division unit can be used to divide the effective value of the PWM signal by the amplitude of the PWM signal to obtain the duty cycle of the PWM signal.

[0096] Optionally, the division unit may include, for example, a divider or any other component that can divide the effective value of the PWM signal by the amplitude of the PWM signal. The present application does not limit this. Exemplarily, the amplitude of the above PWM signal may also be detected by the division unit.

[0097] Optionally, the implementation manner of the effective value acquisition unit extracting the effective value of the PWM signal may refer to the structure of the test parameter value extraction module when the target test parameter is the effective value of the PWM signal described in any of the foregoing embodiments. The present application does not limit this.

[0098] Alternatively, in some embodiments, the effective value acquisition unit may include: a charging sub-unit and a discharging sub-unit. Among them, the charging sub-unit is connected to the discharging sub-unit. The discharging sub-unit can be connected to the result indication module through the division unit.

[0099] The above charging sub-unit can be used to receive a PWM signal and charge through the PWM signal, so that the voltage on the charging sub-unit is used to represent the effective value of the PWM signal. Exemplarily, the charging electronic unit may include devices such as capacitors that can be used for charging. The charging sub-unit can charge the capacitor through the PWM signal, so that the voltage across the capacitor can be used to represent the effective value of the PWM signal.

[0100] The above discharging sub-unit can be used to discharge when the amplitude of the PWM signal is zero. In some embodiments, the discharging sub-unit may include components such as resistors that can receive discharge. Or, Figure 10 This is a schematic structural diagram of a discharging sub-unit provided by the present application. As Figure 10 shown, in some embodiments, the discharging sub-unit may include: a buffer and a discharging resistor. The above charging sub-unit can be connected to one end of the discharging resistor and one end of the division unit through the buffer, and the other end of the discharging resistor can be grounded.

[0101] In this implementation manner, the buffer can be used to isolate the impedance between the charging sub-unit and the discharging resistor. Among them, the discharging sub-unit can discharge through the discharging resistor. Through the above method, discharging through the discharging resistor is realized.

[0102] In some embodiments, the discharging resistor may also be connected in parallel with a filtering capacitor. Through the filtering capacitor, the stability of the current flowing through the discharging resistor can be ensured, thereby improving the safety of using the discharging sub-unit.

[0103] Still taking the duty cycle of the PWM signal as the target test parameter as an example, Figure 11 This is a schematic structural diagram of another signal testing device provided by the present application. As Figure 11 shown, as a possible implementation manner, the test parameter value extraction module may include: an effective value acquisition unit, a division unit, and a comparison unit.

[0104] Among them, the above effective value acquisition unit can be connected to the comparison unit through the division unit. The comparison unit can be connected to the result indication module. As mentioned above, the effective value acquisition unit can be used to receive the PWM signal for representing the target instruction output by the control device to be tested and extract the effective value of the PWM signal. The division unit can be used to divide the effective value of the PWM signal by the amplitude of the PWM signal to obtain the duty cycle of the PWM signal.

[0105] As Figure 11As shown, the comparison unit may include at least one comparison subunit. Among them, each comparison subunit may be connected to an indication unit. In this implementation, the comparison subunits corresponding to the duty cycles of different PWM signals are different. When the comparison subunits outputting the first level are different, the number of lit indicator lights is different. It should be understood that the number of comparison subunits may be the same as the number of indication units. Figure 11 Only an exemplary description of the signal testing device is given by taking the number of 3 comparison subunits as an example.

[0106] Optionally, any of the above comparison subunits may be, for example, a comparator.

[0107] Through the above comparison subunits, the detection results of the duty cycle of PWM are displayed by different numbers of indicator lights, laying a foundation for displaying the test results of PWM signals.

[0108] Exemplarily, still taking the foregoing target test parameter as the duty cycle of the PWM signal and the number of indicator lights as N as an example, Figure 12 This is a schematic structural diagram of another signal testing device provided by the present application. As Figure 12 shown, the main control MCU may be, for example, the main control MCU of a refrigerator. The main control MCU may serve as the foregoing control device to be tested. The above effective value acquisition unit may include a buffer and an effective value extraction module as shown in Figure 12 . The above division unit may include the above divider. The above comparison unit may include the above comparator.

[0109] Based on the signal testing device as shown in Figure 12 , taking the signal testing device that can also be called a test fixture as an example, Figure 13 This is a schematic structural diagram of another signal testing device provided by the present application. As Figure 13 shown, among them, the resistor R1 and the buffer U1 constitute a buffer unit. The resistor R2 and the capacitor C1 may constitute a charging subunit. The resistor R10 may serve as the above discharge resistor. The capacitor C2 may serve as the filter capacitor of the resistor R10. The resistor R3 and the buffer U2 may serve as the buffer between the charging subunit and the discharge resistor. The divider is grounded through the voltage V1. The comparator U3 and the resistors R4 and R5 constitute a comparison subunit (the comparator U4 and the resistors R6 and R7 constitute a comparison subunit, the comparator U5 and the resistors R8 and R9 constitute a comparison subunit), and ZD1, ZD2, and ZD3 are all voltage stabilizing diodes. LED1, LED2, and LED3 are indicator lights.

[0110] Exemplarily, during the function self-check of the electronic control board (such as the foregoing main control MCU), the main control MCU periodically and cyclically outputs corresponding PWM, and the effective value is the value required for the speed regulation of the corresponding load of the refrigerator, such as 3.3V, 5V, 9V, etc.

[0111] The PWM signal passes through the buffer composed of U1, R1, and C2 to effectively isolate the impedance from the PWM output circuit, avoiding the PWM signal being pulled down due to impedance reasons. The PWM signal passing through the buffer charges C1 through R2, and finally the voltage on C1 is the effective value of the PWM. The effective value of the PWM passes through the buffer composed of U2, R3, and C3 to effectively isolate the impedance from loads such as LED1, avoiding the effective value of the PWM being pulled down due to impedance reasons.

[0112] The output of the divider is the effective value of the PWM / V1, which is the duty cycle, and this value is 0 < duty cycle < 1. Where V1 is the amplitude of the PWM (for example, the amplitude is 3.3V, 5V, or 12V, etc.). The reference voltages of the comparator are set to 0.3, 0.5, 0.8, etc. (determined by the MCU program design of the main control board) through resistors R4, R5, R6, R7, R8, R9, etc.

[0113] If the effective value of the PWM is 0.3, the output of comparator U3 is high level, the voltage regulator diode ZD1 breaks down and conducts, and LED1 lights up, indicating that the current PWM duty cycle is 0.3. If the effective value of the PWM is 0.5, the output of comparator U4 is high level, the voltage regulator diodes ZD1 and ZD2 break down and conduct, and LED1 and LED2 light up, indicating that the current PWM duty cycle is 0.5. If the effective value of the PWM is 0.8, the output of comparator U5 is high level, the voltage regulator diodes ZD1, ZD2, and ZD3 break down and conduct, and LED1, LED2, and LED3 light up, indicating that the current PWM duty cycle is 0.8. When the PWM duty cycle is other values, the same applies.

[0114] In this embodiment, only several components are needed to complete the determination of several known PWM duty cycles, without the participation of software, and it also avoids the cumbersome work of using an oscilloscope at the test site. It can be visually confirmed, improving the efficiency of PWM duty cycle detection. By visually detecting and judging the PWM duty cycle output by the main control MCU at a certain moment, it more effectively saves the time required for detecting the performance of the electronic control board circuit and avoids the necessity of building tooling equipment and the inconvenience brought by using an oscilloscope at the test site, further improving the efficiency of PWM duty cycle detection.

[0115] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0116] For ease of explanation, the foregoing has been described in connection with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be derived in accordance with the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and actual applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A signal testing device, characterized in that, The signal testing device includes: a test parameter value extraction module and a result indication module, and the test parameter value extraction module is connected to the result indication module; The test parameter value extraction module is configured to receive a PWM signal for characterizing a target instruction output by a control device to be tested, and extract the value of a target test parameter of the PWM signal; The result indication module is configured to display a test result corresponding to the value of the target test parameter; the test result is used to characterize whether the value of the target test parameter is a target value.

2. The signal testing device according to claim 1, wherein The result indication module includes a plurality of indication units, and each indication unit includes: an indicator light; The result indication module is configured to control the indicator lights of at least one indication unit corresponding to the value of the target test parameter to be turned on according to the value of the target test parameter; when the indicator lights of different numbers of the indication units are turned on, the characterized target values are different.

3. The signal testing device according to claim 2, wherein Each indication unit further includes: a voltage stabilizing sub-unit, and the test parameter value extraction module is connected to the indicator light through the voltage stabilizing sub-unit; When the value of the target test parameter reaches the breakdown conduction condition of the voltage stabilizing sub-unit, the voltage stabilizing sub-unit conducts, so that the indicator light connected to the voltage stabilizing sub-unit is turned on.

4. The signal testing device according to any one of claims 1-3, characterized in that, The target test parameter is the effective value of the PWM signal; the test parameter value extraction module includes: a first buffer unit and a sampling unit, and the first buffer unit is connected to the result indication module through the sampling unit; The first buffer unit is configured to receive a PWM signal for characterizing a target instruction output by the control device to be tested, and perform impedance isolation between the PWM signal output circuit of the control device to be tested and the sampling unit; The sampling unit is configured to extract the effective value of the PWM signal.

5. The signal testing device according to claim 4, characterized in that, The sampling unit includes: a first resistor and a first capacitor, a first end of the first resistor is connected to the first buffer unit, a second end of the first resistor is connected to a first end of the first capacitor and the result indication module, and a second end of the first capacitor is grounded; The PWM signal charges the first capacitor through the first resistor, and the voltage on the first capacitor is used to characterize the effective value of the PWM signal.

6. The signal testing device according to claim 4, wherein The test parameter value extraction module further includes: a second buffer unit, and the sampling unit is connected to the result indication module through the second buffer unit; The second buffer unit is configured to perform impedance isolation between the sampling unit and the result indication module.

7. The signal testing device according to any one of claims 1 to 3, characterized in that The target test parameter is the duty cycle of the PWM signal; The test parameter value extraction module includes: an effective value acquisition unit and a division unit, and the effective value acquisition unit is connected to the result indication module through the division unit; The effective value acquisition unit is configured to receive a PWM signal for characterizing a target instruction output by the control device to be tested, and extract the effective value of the PWM signal; The division unit is configured to divide the effective value of the PWM signal by the amplitude of the PWM signal to obtain the duty cycle of the PWM signal.

8. The signal testing device according to claim 7, wherein The effective value acquisition unit includes: a charging sub-unit and a discharging sub-unit, the charging sub-unit is connected to the discharging sub-unit; the discharging sub-unit is connected to the result indication module through the division unit; The charging sub-unit is configured to receive the PWM signal and charge through the PWM signal, so that the voltage on the charging sub-unit is used to represent the effective value of the PWM signal; The discharging sub-unit is configured to discharge when the amplitude of the PWM signal is zero.

9. The signal testing device according to claim 8, wherein, The discharging sub-unit includes: a buffer and a discharging resistor, the charging sub-unit is connected to one end of the discharging resistor and one end of the division unit through the buffer, and the other end of the discharging resistor is grounded; The buffer is configured to perform impedance isolation between the charging sub-unit and the discharging resistor; the discharging sub-unit discharges through the discharging resistor.

10. The signal testing device according to claim 2, wherein, The target test parameter is the duty cycle of the PWM signal; the test parameter value extraction module includes: an effective value acquisition unit, a division unit, and a comparison unit, the effective value acquisition unit is connected to the comparison unit through the division unit, and the comparison unit is connected to the result indication module; The effective value acquisition unit is configured to receive the PWM signal for representing the target instruction output by the to-be-tested control device and extract the effective value of the PWM signal; The division unit is configured to divide the effective value of the PWM signal by the amplitude of the PWM signal to obtain the duty cycle of the PWM signal; The comparison unit includes at least one comparison sub-unit, each comparison sub-unit is connected to one indication unit; the comparison sub-units corresponding to different duty cycles of the PWM signal for outputting the first level are different; when the comparison sub-units for outputting the first level are different, the number of lit indicator lights is different.

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