VGA signal testing device

Abstract

The VGA signal testing device provided by the embodiment of the utility model comprises a connector, the first end of which is used for connecting a VGA signal source; the EEPROM is used for burning and storing attribute data of the extended display; the DDC signal line is connected with the second end of the connector and the memory; the second end of the three-primary-color signal line is connected with the first resistor after being connected with the first test probe of the first test device; the first end of the SYNC signal line is connected with the second end of the connector, and the second end of the SYNC signal line is connected with the end of the second resistor after being connected with a third test probe of the second test device; the first test probe and the third test probe are also used for connecting an oscilloscope. According to the scheme, the signal source can perform VGA video signal output at the highest resolution; moreover, compatibility testing is facilitated, and the testing cost is reduced; the test space is increased, the test probe is convenient to place, spot test can be carried out, and the test convenience is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of image signal testing, in particular to a VGA signal testing device. Background Art

[0002] VGA (Video Graphics Array) signals are used to transmit video images, with a maximum resolution of up to 1920x1080p at 60Hz, making them high-speed signals. The RGB (Red, Green, and Blue) signals used to transmit these signals are analog signals, which are sensitive to accuracy and prone to interference. Improper signal processing can lead to product instability, such as screen flickering and artifacts. Therefore, it is necessary to test the electrical characteristics of the VGA signal at its output.

[0003] Traditionally, testing VGA signals requires a working connection, meaning a cable and a monitor are required to establish a proper VGA transmission environment. For VGA interfaces designed only to test the signal source, this introduces unnecessary interference. For example, different VGA cables and monitors vary, introducing numerous uncontrollable environmental variables into the signal source's VGA electrical characteristics. Therefore, a device that can output VGA signals properly without the need for cables or a monitor is needed.

[0004] Testing VGA signals on a printed circuit board (PCB) presents the following challenges: The space is too small to easily place the test probe; the VGA pins on the PCB are closely spaced and arranged, making measurement difficult; and monitors vary from manufacturer to manufacturer, meaning their EDID (Extended Display Identification Data) also differs. Testing the signal source's compatibility with multiple monitors requires purchasing multiple monitors, which can increase costs. Utility Model Content

[0005] The utility model provides a VGA signal testing device, which can at least solve some problems existing in the prior art.

[0006] To achieve the above objectives, the present application adopts the following technical solution: a VGA signal testing device, which is arranged on a PCB board and includes:

[0007] A connector, wherein a first end of the connector is used to connect to a VGA signal source;

[0008] EEPROM memory, used for burning and storing extended display attribute data;

[0009] A DDC signal line connecting the second end of the connector and the EEPROM memory, the DDC signal line being used to transmit the extended display attribute data to the connector and to transmit the VGA signal source attribute data to the EEPROM memory;

[0010] Three primary color signal lines, including an R signal line, a G signal line, and a B signal line, wherein a first end of each of the three primary color signal lines is connected to the second end of the connector, and a second end of each of the three primary color signal lines is connected to a first test probe of a first test device and then terminated with a first resistor;

[0011] a SYNC signal line, wherein a first end of the SYNC signal line is connected to the second end of the connector, a second end of the SYNC signal line is connected to a third test probe of a second test device, and then terminated with a second resistor;

[0012] The first test probe and the third test probe are also used to connect to an oscilloscope.

[0013] Optionally, the first test device further includes a second test probe, which is grounded; the second test device further includes a fourth test probe, which is grounded.

[0014] Optionally, the first test probe is connected to a probe of the oscilloscope, and the second test probe is connected to a ground terminal of the oscilloscope;

[0015] The third test probe is connected to the oscilloscope probe, and the fourth test probe is connected to the ground terminal of the oscilloscope.

[0016] Optionally, the resistance of the first resistor is 75 ohms, and the resistance of the second resistor is 2.2 kilo-ohms.

[0017] Optionally, the distance between the first test probe and the second test probe is 2.54 mm.

[0018] Optionally, the SYNC signal line includes an HSYNC signal line and a VSYNC signal line.

[0019] Optionally, the first end of the connector is further connected to a power source, and the power source supplies power to the PCB board and the EEPROM memory through a power signal line between the connector and the EEPROM memory.

[0020] Optionally, the first end of the DDC signal line is connected to the second end of the connector, the second end of the DDC signal line is connected to a fifth test probe of a third test device, and the sixth test probe of the third test device is grounded;

[0021] The first end of the power signal line is connected to the second end of the connector, the second end of the power signal line is connected to the seventh test probe of the fourth test device, and the eighth test probe of the fourth test device is grounded.

[0022] Optionally, the fifth test probe is connected to a probe of the oscilloscope, and the sixth test probe is connected to a ground terminal of the oscilloscope;

[0023] The seventh test probe is connected to the oscilloscope probe, and the eighth test probe is connected to the ground terminal of the oscilloscope.

[0024] Optionally, the resolution of the extended display attribute data is at least 1920x1080P, and the refresh rate is at least 60 Hz.

[0025] The beneficial effects of the technical solution provided by the embodiment of the utility model include at least:

[0026] The VGA signal test device provided by the embodiment of the utility model is arranged on a PCB board and includes: a connector, a first end of the connector is used to connect to a VGA signal source; an EEPROM memory is used to burn and store extended display attribute data; a DDC signal line is connected to the second end of the connector and the EEPROM memory, the DDC signal line is used to transmit the extended display attribute data to the connector and transmit the VGA signal source attribute data to the EEPROM memory; three primary color signal lines, the three primary color signal lines have three, including an R signal line, a G signal line and a B signal line, the first end of each of the three primary color signal lines is connected to the second end of the connector, the second end of the three primary color signal line is connected to the first test probe of the first test device, and then terminated with a first resistor; a SYNC signal line, the first end of the SYNC signal line is connected to the second end of the connector, the second end of the SYNC signal line is connected to the third test probe of the second test device, and then terminated with a second resistor; the first test probe and the third test probe are also used to connect to an oscilloscope. This solution burns and stores extended display attribute data in EEPROM. EEPROM simulates a display, allowing the signal source to output VGA video signals at the highest resolution even without cables and a display. Furthermore, the display attribute parameters of each manufacturer can be freely configured in the EEPROM memory, facilitating compatibility testing and reducing testing costs. Furthermore, by configuring the test parameters on the host and performing the test on the PCB of the VGA signal test device, compared to testing on the signal source's PCB, this increases test space, facilitates the placement of test probes, and enables point testing, improving test convenience. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention provides a schematic diagram of a VGA test device. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] Figure 1 A schematic diagram of a VGA signal testing device provided by an embodiment of the present utility model.

[0030] like Figure 1As shown, the VGA signal test device is set on the PCB board, including a connector, an EEPROM memory, a DDC signal line, R / G / B three primary color signal lines, and a SYNC signal line.

[0031] The connector is used to connect to a VGA signal source. This connector can be a plug-in VGA male connector. A VGA male connector refers to the male portion of a VGA interface, i.e., the plug end. A VGA interface is used to connect graphics cards and monitors to transmit video signals. The male portion of a VGA interface typically has 15 pins, which, according to specific definitions, transmit the three primary colors (red, green, and blue) as well as horizontal and vertical synchronization signals, enabling video image display.

[0032] Figure 1 The left end of the middle connector is the first end, which is used to connect to the VGA signal source. VGA signals mainly include the three primary color signals of red (R), green (G), and blue (B), as well as the horizontal synchronization signal (HSYNC) and the vertical synchronization signal (VSYNC). These signals are transmitted through the connector.

[0033] EEPROM (Electrically Erasable Programmable read-only memory) memory is used to burn and store EDID data (Extended Display Identification Data). EDID data is typically stored in the display's DDC memory. When a computer is connected to the display, it reads the EDID stored in the display's DDC memory through the DDC channel. This solution stores EDID data in EEPROM, which acts like a simulated display. Burning and storing EDID data in EEPROM allows for the proper transmission of a VGA signal.

[0034] This solution burns and stores extended display attribute data in EEPROM, which effectively simulates a display. This allows the signal source to output VGA video signals at the highest resolution, even without cables or a display. Furthermore, display attribute parameters from various manufacturers can be freely configured in the EEPROM, facilitating compatibility testing and reducing testing costs.

[0035] The size of VGA EDID is 128 bytes. To meet the test requirements, the burned-in EDID data must have a resolution of at least 1920x1080P and a refresh rate of 60HZ.

[0036] The DDC signal line (DDC) is the data channel through which the connector accesses the extended display attribute data stored in the EEPROM and also the data channel through which the EEPROM accesses the VGA signal source attribute data. The DDC channel enables the connector to directly read various extended display parameters (such as resolution and aspect ratio) stored in the EEPROM and enables the EEPROM to access the VGA signal source attribute data, thereby simplifying the configuration process between the connector and the EEPROM.

[0037] The three primary color signal lines include R (Red), G (Green) and B (Blue) signal lines, which are located on the PCB board. There are 3 lines in total. The first end of each signal line is connected to the second end of the connector. The second end of each signal line is connected to the first test device and then terminated with a 75 ohm resistor.

[0038] Terminating the three primary color signal lines with 75 ohms ensures that the voltage drop meets the specifications when the VGA signal is transmitted normally, making the electrical characteristics comply with the VESA (Video Electronics Standards Association) standards.

[0039] The first test device includes two test probes, namely a first test probe and a second test probe, wherein the first test probe is connected to a three-primary color signal line, and the second test probe is grounded.

[0040] Since there are three primary color signal lines, there are three first test devices. Assuming the three first test devices are test device A, test device B, and test device C, then the first test probe of test device A is connected to the R signal line, and the second test probe is grounded; the first test probe of test device B is connected to the G signal line, and the second test probe is grounded; the first test probe of test device C is connected to the B signal line, and the second test probe is grounded.

[0041] The test probes are 2-pin probes with a spacing of 2.54mm between them. Setting a spacing of 2.54mm allows for sufficient spacing between the two test probes to allow simultaneous testing of three signal access sensor probes. This makes it easier to position the probes for testing, and the 2.54mm spacing minimizes interference during testing.

[0042] Specifically, the first test probe is connected to the probe head of the oscilloscope, and the second test probe is connected to the ground terminal of the oscilloscope.

[0043] An oscilloscope probe is crucial to the accuracy and correctness of measurement results. It is the electronic component that connects the measured signal to the oscilloscope input. By directing the three primary color signal lines into the oscilloscope, the tester can visually observe the waveform changes of the three primary color signals and test their electrical characteristics.

[0044] The SYNC signal line includes the HSYNC (horizontal synchronization signal) signal line and the VSYNC signal line (field synchronization signal). The function of the horizontal synchronization signal is to select the effective horizontal signal interval on the liquid crystal panel, and the function of the field synchronization signal is to select the effective field signal interval on the liquid crystal panel.

[0045] The HSYNC signal line and the VSYNC signal line are located on the PCB board. The first end of each signal line is connected to the second end of the connector. The second end of each signal line is connected to the second test device and then terminated with a 2.2 kilo-ohm resistor.

[0046] Terminating the SYNC signal line with 2.2 kilo-ohm termination also ensures that the VGA signal generates a voltage drop that meets the specifications during normal transmission, making the electrical characteristics comply with the VESA standard.

[0047] The second test device also includes two test probes, namely a third test probe and a fourth test probe, wherein the third test probe is connected to a SYNC signal line, and the fourth test probe is grounded.

[0048] The test probes are 2-pin probes with a spacing of 2.54mm between them. Setting a spacing of 2.54mm allows for sufficient spacing between the two test probes to allow simultaneous testing of two signal sensor probes. This makes it easier to position the probes for testing, and the 2.54mm spacing minimizes interference during testing.

[0049] Since there are two SYNC signal lines, there are two second test devices. Assuming the two second test devices are test device D and test device E, the third test probe of test device D is connected to the HSYNC signal line, and the fourth test probe is grounded; the third test probe of test device E is connected to the VSYNC signal line, and the fourth test probe is grounded.

[0050] By configuring test parameters on the host computer and performing tests on the VGA signal test device's PCB, compared to testing on the signal source's PCB, this increases test space, facilitates placement of test probes, and enables point testing, improving test convenience. It also allows for aging testing of the signal source's VGA signal, increasing test diversity.

[0051] Optionally, the third test probe is connected to the oscilloscope probe, and the fourth test probe is connected to the ground terminal of the oscilloscope.

[0052] The oscilloscope probe imports the SYNC signal line into the oscilloscope, so that the tester can visually see the waveform changes of the SYNC signal and test the electrical characteristics of the SYNC signal.

[0053] Optionally, the first end of the connector is also connected to a power source (the power source is Figure 1 The power supply can be a 5V power supply. The power supply provides power to the PCB and the EEPROM memory through a power signal line between the connector and the EEPROM memory.

[0054] like Figure 1 As shown, the power connection line is located between the connector and the EEPROM memory to provide power to the PCB board and the EEPROM memory.

[0055] Optionally, the first end of the DDC signal line is connected to the second end of the connector, the second end of the DDC signal line is connected to the fifth test probe of the third test device, and the sixth test probe of the third test device is grounded;

[0056] The first end of the power signal line is connected to the second end of the connector, the second end of the power signal line is connected to the seventh test probe of the fourth test device, and the eighth test probe of the fourth test device is grounded.

[0057] Optionally, the fifth test probe is connected to the probe of the oscilloscope, and the sixth test probe is connected to the ground terminal of the oscilloscope; the seventh test probe is connected to the probe of the oscilloscope, and the eighth test probe is connected to the ground terminal of the oscilloscope.

[0058] like Figure 1 As shown, the DDC signal line is connected to the test device. This test device is the third test device and includes a fifth test probe and a sixth test probe; the power signal line is connected to the test device. This test device is the fourth test device and includes a seventh test probe and an eighth test probe.

[0059] The fifth test probe is connected to the DDC signal line, the seventh test probe is connected to the power signal line, the fifth test probe and the seventh test probe are also connected to the probe of the oscilloscope respectively, and the sixth test probe and the eighth test probe are grounded.

[0060] The fifth and sixth test probes of the third test device are 3-pin test probes, and the spacing between the two test probes in the third and fourth test devices is still 2.54 mm.

[0061] In summary, the VGA signal test device provided by the embodiment of the present invention is arranged on a PCB board, including: a connector, a first end of the connector is used to connect to a VGA signal source; an EEPROM memory is used to burn and store extended display attribute data; a DDC signal line, connecting the second end of the connector and the EEPROM memory, the DDC signal line is used to transmit the extended display attribute data to the connector, and transmit the VGA signal source attribute data to the EEPROM memory; three primary color signal lines, the three primary color signal lines have three, including an R signal line, a G signal line and a B signal line, the first end of each of the three primary color signal lines is connected to the second end of the connector, the second end of the three primary color signal line is connected to the first test probe of the first test device, and then terminated with a first resistor; a SYNC signal line, the first end of the SYNC signal line is connected to the second end of the connector, the second end of the SYNC signal line is connected to the third test probe of the second test device, and then terminated with a second resistor; the first test probe and the third test probe are also used to connect to an oscilloscope. This solution burns and stores extended display attribute data in EEPROM. EEPROM simulates a display, allowing the signal source to output VGA video signals at the highest resolution even without cables and a display. Furthermore, the display attribute parameters of each manufacturer can be freely configured in the EEPROM memory, facilitating compatibility testing and reducing testing costs. Furthermore, by configuring the test parameters on the host and performing the test on the PCB of the VGA signal test device, compared to testing on the signal source's PCB, this increases test space, facilitates the placement of test probes, and enables point testing, improving test convenience.

[0062] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The above embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the concept of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be based on the appended claims.

Claims

1. A VGA signal testing device, characterized in that: The device is arranged on a PCB board and includes: A connector, wherein a first end of the connector is used to connect to a VGA signal source; EEPROM memory, used for burning and storing extended display attribute data; A DDC signal line connecting the second end of the connector and the EEPROM memory, the DDC signal line being used to transmit the extended display attribute data to the connector and to transmit the VGA signal source attribute data to the EEPROM memory; Three primary color signal lines, including an R signal line, a G signal line, and a B signal line, wherein a first end of each of the three primary color signal lines is connected to the second end of the connector, and a second end of each of the three primary color signal lines is connected to a first test probe of a first test device and then terminated with a first resistor; a SYNC signal line, wherein a first end of the SYNC signal line is connected to the second end of the connector, a second end of the SYNC signal line is connected to a third test probe of a second test device, and then terminated with a second resistor; The first test probe and the third test probe are also used to connect to an oscilloscope.

2. The device according to claim 1, characterized in that The first test device further includes a second test probe, which is grounded; the second test device further includes a fourth test probe, which is grounded.

3. The device according to claim 2, characterized in that The first test probe is connected to the probe of the oscilloscope, and the second test probe is connected to the ground terminal of the oscilloscope; The third test probe is connected to the oscilloscope probe, and the fourth test probe is connected to the ground terminal of the oscilloscope.

4. The device according to claim 1, characterized in that The resistance of the first resistor is 75 ohms, and the resistance of the second resistor is 2.2 kilo-ohms.

5. The device according to claim 2, characterized in that The distance between the first test probe and the second test probe is 2.54 mm.

6. The device according to claim 1, characterized in that The SYNC signal line includes an HSYNC signal line and a VSYNC signal line.

7. The device according to claim 1, characterized in that The first end of the connector is also connected to a power source, and the power source supplies power to the PCB board and the EEPROM memory through a power signal line between the connector and the EEPROM memory.

8. The device according to claim 7, characterized in that The first end of the DDC signal line is connected to the second end of the connector, the second end of the DDC signal line is connected to the fifth test probe of the third test device, and the sixth test probe of the third test device is grounded; The first end of the power signal line is connected to the second end of the connector, the second end of the power signal line is connected to the seventh test probe of the fourth test device, and the eighth test probe of the fourth test device is grounded.

9. The device according to claim 8, characterized in that The fifth test probe is connected to the probe of the oscilloscope, and the sixth test probe is connected to the ground terminal of the oscilloscope; The seventh test probe is connected to the oscilloscope probe, and the eighth test probe is connected to the ground terminal of the oscilloscope.

10. The device according to claim 1, wherein The resolution of the extended display attribute data is at least 1920x1080P, and the refresh rate is at least 60Hz.

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