Signal distributor and test apparatus and method based on signal distributor

Abstract

The application provides a signal distributor, a testing device and a testing method based on the signal distributor, the signal distributor comprises: an isolation transformer module, which is used for receiving a differential signal output by a signal source and performing isolation direct current processing on the differential signal and then outputting; a differential signal receiver, which is connected with the isolation transformer module, is used for receiving the differential signal, and converts the differential signal into a plurality of single-end signals; a plurality of level conversion and impedance matching modules, each of which is connected with the differential signal receiver, receives a single-end signal corresponding to the level conversion and impedance matching module, and converts the single-end signal into a corresponding differential signal output. The application can convert a differential signal into a plurality of differential signal outputs, so that one signal source can be used to test a plurality of devices to be tested, and the testing cost is reduced.

Description

Technical Field

[0001] This application relates to the field of signal processing technology, and in particular to a signal distributor and a test apparatus and method based on the signal distributor. Background Technology

[0002] SPDIF (Sony / Philips Digital Interface) is an abbreviation for the Sony / Philips digital audio interface, widely used in projectors, televisions, and amplifiers. Due to its widespread use, it has now become a consumer digital audio format standard.

[0003] In the R&D and testing of speaker products, one SPDIF source was used to correspond to one device under test (DUT) for load testing under various environments. This testing method requires multiple SPDIF sources when testing multiple DUTs simultaneously, increasing the cost of testing equipment and making it difficult to manage numerous independently operating sources in a unified manner. Summary of the Invention

[0004] This application provides a signal distributor and a testing apparatus and method based on the signal distributor to solve the problem in the prior art that multiple SPDIF signal source devices are required when testing multiple speakers.

[0005] In a first aspect, this application provides a signal distributor, the signal distributor comprising:

[0006] An isolation transformer module is used to receive a differential signal output from a signal source and output the differential signal after DC isolation processing.

[0007] A differential signal receiver, connected to the isolation transformer module, is used to receive differential signals and convert the differential signal into multiple single-ended signals;

[0008] Multiple level conversion and impedance matching modules are provided. Each level conversion and impedance matching module is connected to the differential signal receiver. Each level conversion and impedance matching module receives a single-ended signal and converts the single-ended signal into a corresponding differential signal for output.

[0009] In one embodiment of this application, the signal distributor further includes a power supply module, which includes a DC-DC converter and a linear regulator. The DC-DC converter is connected to the differential signal receiver and the linear regulator, respectively. The linear regulator is connected to each level conversion and impedance matching module, respectively. The DC-DC converter is used to power the differential signal receiver, and the linear regulator is used to power each level conversion and impedance matching module.

[0010] In one embodiment of this application, the isolation transformer module includes an input terminal P1, a first diode D8, a first capacitor C13, a first resistor R5, and an isolation transformer L2;

[0011] The input terminal P1 is connected to the first terminal of the first diode D8 and the second terminal of the first capacitor C13. The first terminal of the first capacitor C13 is connected to the first terminal of the first resistor R5 and the fourth terminal of the primary winding of the isolation transformer L2. The second terminal of the first diode D8, the second terminal of the first resistor R5 and the third terminal of the primary winding are all grounded. The secondary winding of the isolation transformer L2 is connected to the differential signal receiver.

[0012] The input terminal P1 receives the differential signal, which is isolated from the DC component by the first capacitor C13, and then impedance matched by the first resistor R5 before being input to the primary winding of the isolation transformer L2. The secondary winding of the isolation transformer L2 outputs the differential signal.

[0013] In one embodiment of this application, the differential signal receiver includes a differential signal to single-ended signal chip U3, a second resistor R6, and a second capacitor C14;

[0014] The first pin of the differential signal to single-ended signal chip U3 is connected to the second end of the secondary winding of the isolation transformer L2, the second pin is connected to the first end of the secondary winding of the isolation transformer L2, the third pin is connected in series with the second resistor R6 and then connected to each level conversion and impedance matching module, the eighth pin is grounded, the sixteenth pin is connected to the DC to DC converter, and the sixteenth pin is connected in series with the second capacitor C14 and then grounded.

[0015] In one embodiment of this application, each level conversion and impedance matching module includes a third capacitor C17, a fourth capacitor C20, a fifth capacitor C23, a sixth capacitor C26, a first transistor Q3, a third resistor R9, a fourth resistor R12, and a second diode D3.

[0016] The input terminal of each level conversion and impedance matching module is connected to the second terminal of the fourth capacitor C20 and the base of the first transistor Q3, respectively. The second terminal of the third capacitor C17 is connected to the collector of the first transistor Q3 and the linear regulator, respectively. The first terminal of the third capacitor C17 is grounded. The emitter of the first transistor Q3 is connected to the first terminal of the third resistor R9. The second terminal of the third resistor R9 is connected to the first terminal of the fourth resistor R12 and the second terminal of the fifth capacitor C23, respectively. The first terminal of the fifth capacitor C23 is connected to the second terminal of the sixth capacitor C26, the first terminal of the second diode D3 and the output terminal P4, respectively. The first terminals of the fourth capacitor C20, the fourth resistor R12, the sixth capacitor C26 and the second terminal of the second diode D3 are all grounded.

[0017] The first transistor Q3 is turned on and off by receiving a single-ended signal from the differential signal receiver. When the first transistor Q3 is turned on, the power signal from the linear regulator is divided by the third resistor R9 and the fourth resistor R12, making the voltage across the fourth resistor R12 the first voltage. When the first transistor Q3 is turned off, the voltage across the fourth resistor R12 becomes the second voltage.

[0018] The single-ended signal controls the switching on and off of the first transistor Q3 and drives the output through the power supply signal. The single-ended signal is converted into a differential signal across the fourth resistor R12. The differential signal is impedance matched by adjusting the resistance value of the fourth resistor R12 and output from the output terminal P4 after isolating the DC component through the fifth capacitor C23.

[0019] In one embodiment of this application, the signal source is an SPDIF signal source, which is connected to the isolation transformer module via an audio cable RCA. Each level conversion and impedance matching module is connected to the corresponding device under test via an audio cable RCA.

[0020] Secondly, this application also provides a test apparatus based on a signal distributor, the test apparatus including the signal distributor as described in any of the first aspects.

[0021] In one embodiment of this application, the testing apparatus further includes an SPDIF signal source and multiple devices under test (DUTs). The input terminal of the signal distributor is connected to the SPDIF signal source, and the output terminal of the signal distributor is connected to each DUT to test the DUT.

[0022] Thirdly, this application also provides a test method based on a signal distributor, wherein the test method uses a signal distributor as described in any of the first aspects to convert one differential signal into multiple differential signal outputs.

[0023] In one embodiment of this application, the step of converting one differential signal into multiple differential signals for output includes:

[0024] Receive one SPDIF differential signal from an SPDIF source and perform DC isolation processing on the SPDIF differential signal;

[0025] The SPDIF differential signal after isolation DC processing is converted into multiple single-ended signals, and each single-ended signal is converted into a corresponding differential signal.

[0026] Each differential signal is input to the corresponding device under test (DUT) for testing. This application provides a signal distributor and a test apparatus and method based on the signal distributor. After isolating a single differential signal to DC power using an isolation transformer module, the signal is converted into multiple single-ended signals by a differential signal receiver. Finally, multiple level conversion and impedance matching modules convert the single-ended signals back into corresponding multi-differential signal outputs. Thus, this application can convert a single differential signal into multiple differential signal outputs, enabling the testing of multiple DUTs using a single signal source, thereby reducing testing costs. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of the signal distributor provided in the embodiments of this application;

[0029] Figure 2(a) is an input circuit diagram of the power supply module provided in an embodiment of this application;

[0030] Figure 2(b) is a circuit diagram of the DC-DC converter of the power supply module provided in the embodiment of this application;

[0031] Figure 2(c) is a circuit diagram of the linear regulator of the power supply module provided in the embodiment of this application;

[0032] Figure 3 This is a circuit diagram of the isolation transformer module and differential signal receiver provided in the embodiments of this application;

[0033] Figure 4 This is a circuit diagram of the level matching and conversion module provided in the embodiments of this application;

[0034] Figure 5 This is a schematic diagram of the structure of the testing device provided in the embodiments of this application;

[0035] Figure 6 This is a flowchart illustrating the testing method provided in the embodiments of this application. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0038] The following describes the technical terms used in this application:

[0039] An SPDIF source indicates an SPDIF signal output device that has storage function or the ability to read external storage and perform audio decoding.

[0040] To address the problem in existing technologies that require multiple SPDIF signal source devices when testing multiple speakers, this application provides a signal distributor and a test apparatus and method based on the signal distributor. The provided isolation transformer module isolates a single differential signal for DC processing, then a differential signal receiver converts the single differential signal into multiple single-ended signals. Finally, multiple level conversion and impedance matching modules convert the multiple single-ended signals back into corresponding multi-differential signal outputs. Thus, this application can convert a single differential signal into multiple differential signal outputs, enabling the testing of multiple devices under test using a single signal source, thereby reducing testing costs.

[0041] It should be noted that the signal distributor described in this application is applicable to SPDIF signal sources, and can also be applied to digital signal sources with similar frequencies (e.g., around 3MHz).

[0042] The following is combined Figures 1-6 This application describes the signal distributor and the test apparatus and method based on the signal distributor.

[0043] Please refer to Figure 1 , Figure 1This is a schematic diagram of the signal distributor provided in an embodiment of this application. A signal distributor 100 is used to receive differential signals output from a signal source 150 (e.g., an SPDIF signal source), and converts these differential signals into multiple differential signals for output to corresponding devices under test 160 (e.g., speakers). Each differential signal corresponds to one device under test 160. The signal source 150 is used to generate the signals required for testing the device under test 160.

[0044] For example, the signal distributor 100 includes an isolation transformer module 110, a differential signal receiver 120, and 1 to N level conversion and impedance matching modules 130, where N is a natural number greater than 1.

[0045] Specifically, the isolation transformer module 110 is used to receive a differential signal output from a signal source 150, and output the differential signal after performing DC isolation processing.

[0046] Differential transmission is a signal transmission technique that differs from the traditional method of using one signal line and one ground line (single-ended signal). Differential transmission transmits signals on both lines, with equal amplitude and opposite phase. The signals transmitted on these two lines are called differential signals. Single-ended signals are those that are independent of differential signals; a single-ended input signal consists of a reference terminal and a signal terminal, with the reference terminal typically being ground.

[0047] Specifically, the differential signal receiver 120 is connected to the isolation transformer module 110. The differential signal receiver 120 is used to receive differential signals and convert the differential signals into multiple single-ended signals.

[0048] Specifically, each level conversion and impedance matching module 130 is connected to the differential signal receiver 120, and each level conversion and impedance matching module 130 receives a single-ended signal and converts the single-ended signal into a corresponding differential signal for output.

[0049] For example, a level conversion and impedance matching module 130 outputs a differential signal to a device under test 160. The number of level conversion and impedance matching modules 130 is equal to the number of devices under test 160, and one level conversion and impedance matching module 130 outputs one differential signal.

[0050] In some embodiments of this application, the signal distributor 100 further includes a power supply module 140, which is connected to an external DC input power supply. The power supply module 140 includes a DC-DC converter 141 and a linear regulator 142. The DC-DC converter 141 is connected to the differential signal receiver 120 and the linear regulator 142, respectively. The linear regulator 142 is connected to each level conversion and impedance matching module 130. The DC-DC converter 141 supplies power to the differential signal receiver 120, and the linear regulator 142 supplies power to each level conversion and impedance matching module 130.

[0051] For example, if the external input power supply is 12V, the power supply module 140 converts the external input power supply 12V into a 5V power supply and a 3.3V power supply, where the 5V power supply is used to power the differential signal receiver 120 and the 3.3V power supply is used to power each level conversion and impedance matching module 130.

[0052] It should be noted that the signal source described in this application can be an SPDIF signal source or other digital signal sources with similar frequencies. The SPDIF signal source 150 can be connected to the isolation transformer module 110 via an audio cable RCA (Radio Corporation of American, commonly known as a lotus connector, which is a type of audio and video terminal block). Each level conversion and impedance matching module 130 is connected to the corresponding device under test 160 via an audio cable RCA.

[0053] In one embodiment of this application, SPDIF is a digital audio signal, which can be divided into coaxial and optical fiber in terms of transmission medium. Both methods can transmit the same signal. Optical fiber audio conversion: audio signal -> digital signal -> optical signal -> digital signal -> audio signal; coaxial audio conversion: audio signal -> digital signal -> audio signal. Advantages of coaxial audio interfaces: reduced electro-optical and optical-electrical conversion processes result in higher fidelity. The signal distributor described in this application is suitable for coaxial audio interfaces. If it needs to be applied to optical fiber audio interfaces, it can be achieved by adding a photoelectric conversion module.

[0054] Therefore, this application isolates the input differential signal by DC processing through the isolation transformer module 110, then converts the differential signal into multiple single-ended signals through the differential signal receiver 120, and finally converts the multiple single-ended signals into corresponding multiple differential signals through multiple level conversion and impedance matching modules 130. This allows the conversion of one differential signal into multiple differential signals, enabling the testing of multiple devices under test 160 using only one signal source 150, instead of using one signal source 150 for each device under test 160 as in the prior art, thus reducing testing costs.

[0055] The signal distributor described in this application is illustrated below with specific embodiments.

[0056] Please refer to Figures 2(a), 2(b), and 2(c). Figure 2(a) is an input circuit diagram of the power supply module provided in an embodiment of this application; Figure 2(b) is a DC-DC converter circuit diagram of the power supply module provided in an embodiment of this application; and Figure 2(c) is a linear regulator circuit diagram of the power supply module provided in an embodiment of this application.

[0057] In Figure 2(a), the input circuit of the power supply module includes a DC socket J6, capacitor C40, and capacitor C41. The external input power supply is connected to the first terminal of DC socket J6, the second terminal of capacitor C40, and the second terminal of capacitor C41, respectively. The second and third terminals of DC socket J6, the first terminal of capacitor C40, and the first terminal of capacitor C41 are grounded. When the external input power supply is connected to socket J6, the voltage is filtered by capacitors C40 and C41 before being output. The external input power supply shown in Figure 2(a) is 12V, but this application is not limited to 12V.

[0058] In Figure 2(b), the DC-DC converter circuit mainly converts the 12V power supply in the input circuit to a 5V power output. The DC-DC converter circuit includes chip U1, capacitors C1 to C8, resistors R1 to R4, and inductor L1. The second terminal of capacitors C6, C7, and C8 connected in parallel is connected to the external 12V input power supply, and the first terminal is grounded.

[0059] The first pin of chip U1 is grounded. Its second pin is connected to the first terminal of inductor L1 and the second terminal of capacitor C1. The first terminal of capacitor C1 is connected to the sixth pin of chip U1. The third pin of chip U3 is connected to the first terminal of resistor R2, the second terminal of capacitor C8, the second terminal of capacitor C7, the second terminal of capacitor C6, and the external input power supply. The second terminal of resistor R2 is connected to the fifth pin of chip U1 and the first terminal of resistor R4. The second terminal of resistor R4 is grounded. The fourth pin of chip U1 is connected to the second terminal of resistor R1, the first terminal of capacitor C2, and the first terminal of resistor R3. The first terminal of resistor R1 is connected to the second terminal of inductor L1, the second terminal of capacitor C2 is connected to the second terminal of inductor L1, and the second terminal of resistor R3 is grounded. The second terminals of capacitors C3, C4, and C5 connected in parallel are all connected to the second terminal of inductor L1 and the output terminal. The first terminal of capacitors C3, C4, and C5 connected in parallel is grounded.

[0060] In Figure 2(c), the linear regulator circuit mainly converts the 5V power supply output from the DC-DC converter circuit to a 3.3V power supply output. The linear regulator circuit includes chip U2 and capacitors C9 to C12. The second terminal of capacitors C11 and C12 connected in parallel is connected to the 5V power input terminal and the third pin of chip U2, respectively, while the first terminal of capacitors C11 and C12 connected in parallel is grounded. The fourth pin of chip U2 is connected to the second pin. The first pin of chip U2 is grounded. The second terminal of capacitors C9 and C10 connected in parallel is connected to the second pin and the output terminal of chip U2, respectively, while the first terminal of capacitors C9 and C10 connected in parallel is grounded.

[0061] It should be noted that the circuit in this application... It is a debugging interface, used to provide an interface for oscilloscope debugging.

[0062] Please refer to Figure 3 , Figure 3 This is a circuit diagram of the isolation transformer module and differential signal receiver provided in an embodiment of this application. The isolation transformer module includes an input terminal P1, a diode D8, a capacitor C13, a resistor R5, and an isolation transformer L2. The input terminal P1 is connected to the first terminal of the diode D8 and the second terminal of the capacitor C13. The first terminal of the capacitor C13 is connected to the first terminal of the resistor R5 and the fourth terminal of the primary winding of the isolation transformer L2. The second terminal of the diode D8, the second terminal of the resistor R5, and the third terminal of the primary winding are all grounded. The secondary winding of the isolation transformer L2 is connected to the differential signal receiver.

[0063] Diode D8 is an ESD (Electro-Static Discharge) diode used for electrostatic discharge protection. Resistor R5 is an impedance matching resistor, used to match the impedance of the input signal, reducing signal loss. Impedance matching is mainly used on transmission lines to ensure that all high-frequency microwave signals can be transmitted to the load point with minimal signal reflection back to the source, thus improving energy efficiency.

[0064] The input terminal P1 receives the differential signal, which has its DC component isolated by capacitor C13, then undergoes impedance matching through resistor R5 before being input to the primary winding of isolation transformer L2. The secondary winding of isolation transformer L2 then outputs the differential signal. Isolation transformer L2 reduces external signal interference and prevents accidental high voltage from damaging the input source, thus providing protection.

[0065] See again Figure 3The differential signal receiver includes a differential signal to single-ended signal chip U3, a resistor R6, and a capacitor C14. The first pin of the differential signal to single-ended signal chip U3 is connected to the second end of the secondary winding of the isolation transformer L2. The second pin of the differential signal to single-ended signal chip U3 is connected to the first end of the secondary winding of the isolation transformer L2. The third pin of the differential signal to single-ended signal chip U3 is connected in series with the resistor R6 and then connected to each level conversion and impedance matching module. The eighth pin of the differential signal to single-ended signal chip U3 is grounded. The sixteenth pin of the differential signal to single-ended signal chip U3 is connected to the DC-DC converter, and the sixteenth pin is connected in series with the capacitor C14 and then grounded.

[0066] It should be noted that this application uses a differential signal to single-ended signal chip U3 to realize the function of converting differential signals to single-ended signals, which can reduce the implementation cost.

[0067] Therefore, the DC-DC converter converts the externally input 12V power supply to 5V and outputs it to pin 16 of the differential signal to single-ended signal chip U3, serving as the power supply for U3. The secondary winding of the isolation transformer L2 outputs the differential signal to pins 1 and 2 of the differential signal to single-ended signal chip U3. U3 then converts the differential signal to a 5V single-ended signal, which is output from pin 3 to each level conversion and impedance matching module at the back end.

[0068] Please refer to Figure 4 , Figure 4 This is a circuit diagram of the level matching and conversion module provided in the embodiments of this application. The circuit of each level matching and conversion module is as follows: Figure 4 As shown, each level conversion and impedance matching module includes capacitors C17, C20, C23, and C26, transistor Q3, resistors R9 and R12, and diode D3.

[0069] The input terminal of each level shifter and impedance matching module (i.e. Figure 4 The SPDIF (5V) shown is connected to the second terminal of capacitor C20 and the base of transistor Q3, respectively. The second terminal of capacitor C17 is connected to the collector of transistor Q3 and the output terminal of the linear regulator (i.e., the 3.3V power supply), respectively. The first terminal of capacitor C17 is grounded. The emitter of transistor Q3 is connected to the first terminal of resistor R9. The second terminal of resistor R9 is connected to the first terminal of resistor R12 and the second terminal of capacitor C23, respectively. The first terminal of capacitor C23 is connected to the second terminal of capacitor C26, the first terminal of diode D3 and the output terminal P4, respectively. The first terminals of capacitor C20, resistor R12, capacitor C26 and diode D3 are all grounded.

[0070] The transistor Q3 is switched on and off by receiving a single-ended signal (i.e., SPDIF_5V) from the differential signal receiver. When transistor Q3 is on, the power supply signal (e.g., 3.3V) from the linear regulator is divided by resistors R9 and R12, resulting in a first voltage (e.g., 1V) across resistor R12. When transistor Q3 is off, the voltage across resistor R12 becomes a second voltage (e.g., 0V).

[0071] It should be noted that this application controls the switching of transistor Q3 using a 5V single-ended signal, and performs voltage division using resistors R9 and R12. The signal across resistor R12 after voltage division is considered a differential signal. The 3.3V power supply signal is used to provide a high-level voltage; this application drives the output using the 3.3V power supply signal, rather than directly driving it with a 5V single-ended signal.

[0072] Therefore, this application controls the switching of transistor Q3 using a 5V single-ended signal and drives the output with a 3.3V power supply. This converts the 5V single-ended signal into a differential signal across resistor R12 (e.g., the amplitude of this differential signal is approximately 1V). The differential signal can be impedance matched by adjusting the resistance value of resistor R12, and after DC component isolation by capacitor C23, it is output from output terminal P4 to the corresponding device under test. This achieves the conversion of one differential signal into multiple differential signal outputs, enabling the testing of multiple devices under test using a single signal source, thus reducing testing costs.

[0073] The test apparatus based on a signal distributor provided in this application is described below. The test apparatus based on a signal distributor described below can be referred to in correspondence with the signal distributor described above.

[0074] In some embodiments of this application, a test apparatus based on a signal distributor is also provided, the test apparatus including the signal distributor 100 as described above.

[0075] For example, such as Figure 5 As shown, the test apparatus also includes an SPDIF signal source 150 and multiple devices under test 160. The input terminal of the signal distributor 100 is connected to the SPDIF signal source 150, and the output terminal of the signal distributor 100 is connected to each device under test 160 to test the device under test 160.

[0076] In some embodiments of this application, this application also provides a test method based on a signal distributor, wherein the test method uses the signal distributor as described above to convert one differential signal into multiple differential signal outputs.

[0077] For example, such as Figure 6As shown, the step of converting one differential signal into multiple differential signals for output includes:

[0078] Step 510: Receive one SPDIF differential signal output from an SPDIF source and perform DC isolation processing on the SPDIF differential signal.

[0079] Step 520: Convert the isolated DC processed SPDIF differential signal into multiple single-ended signals, and convert each single-ended signal into a corresponding differential signal.

[0080] Step 530: Input each differential signal to the corresponding device under test for testing.

[0081] It should be noted that the above-mentioned test method based on the signal distributor provided in this application embodiment can achieve the functions implemented by the above-mentioned signal distributor embodiment and can achieve the same technical effect. Here, the parts that are the same as those in the signal distributor embodiment and the beneficial effects will not be described in detail.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A signal distributor, characterized in that, The signal distributor includes: An isolation transformer module is used to receive a differential signal output from a signal source and output the differential signal after DC isolation processing. A differential signal receiver, connected to the isolation transformer module, is used to receive differential signals and convert the differential signal into multiple single-ended signals; Multiple level conversion and impedance matching modules are provided. Each level conversion and impedance matching module is connected to the differential signal receiver. Each level conversion and impedance matching module receives a single-ended signal and converts the single-ended signal into a corresponding differential signal for output.

2. The signal distributor according to claim 1, characterized in that, The signal distributor also includes a power supply module, which includes a DC-DC converter and a linear regulator. The DC-DC converter is connected to the differential signal receiver and the linear regulator, respectively. The linear regulator is connected to each level conversion and impedance matching module. The DC-DC converter is used to power the differential signal receiver, and the linear regulator is used to power each level conversion and impedance matching module.

3. The signal distributor according to claim 1 or 2, characterized in that, The isolation transformer module includes an input terminal (P1), a first diode (D8), a first capacitor (C13), a first resistor (R5), and an isolation transformer (L2); The input terminal (P1) is connected to the first terminal of the first diode (D8) and the second terminal of the first capacitor (C13) respectively. The first terminal of the first capacitor (C13) is connected to the first terminal of the first resistor (R5) and the fourth terminal of the primary winding of the isolation transformer (L2) respectively. The second terminal of the first diode (D8), the second terminal of the first resistor (R5) and the third terminal of the primary winding are all grounded. The secondary winding of the isolation transformer (L2) is connected to the differential signal receiver. The input terminal (P1) receives the differential signal, isolates the DC component through the first capacitor (C13), then performs impedance matching through the first resistor (R5) and inputs it to the primary winding of the isolation transformer (L2). The secondary winding of the isolation transformer (L2) outputs the differential signal.

4. The signal distributor according to claim 3, characterized in that, The differential signal receiver includes a differential signal to single-ended signal chip (U3), a second resistor (R6), and a second capacitor (C14); The first pin of the differential signal to single-ended signal chip (U3) is connected to the second end of the secondary winding of the isolation transformer (L2), the second pin is connected to the first end of the secondary winding of the isolation transformer (L2), the third pin is connected in series with the second resistor (R6) and then connected to each level conversion and impedance matching module respectively, the eighth pin is grounded, the sixteenth pin is connected to the DC to DC converter, and the sixteenth pin is connected in series with the second capacitor (C14) and then grounded.

5. The signal distributor according to claim 2, characterized in that, Each level shifting and impedance matching module includes a third capacitor (C17), a fourth capacitor (C20), a fifth capacitor (C23), a sixth capacitor (C26), a first transistor (Q3), a third resistor (R9), a fourth resistor (R12), and a second diode (D3); The input terminal of each level conversion and impedance matching module is connected to the second terminal of the fourth capacitor (C20) and the base of the first transistor (Q3), respectively. The second terminal of the third capacitor (C17) is connected to the collector of the first transistor (Q3) and the linear regulator, respectively. The first terminal of the third capacitor (C17) is grounded. The emitter of the first transistor (Q3) is connected to the first terminal of the third resistor (R9). The second terminal of the third resistor (R9) is connected to the first terminal of the fourth resistor (R12) and the second terminal of the fifth capacitor (C23), respectively. The first terminal of the fifth capacitor (C23) is connected to the second terminal of the sixth capacitor (C26), the first terminal of the second diode (D3), and the output terminal (P4), respectively. The first terminals of the fourth capacitor (C20), the fourth resistor (R12), the sixth capacitor (C26), and the second terminal of the second diode (D3) are all grounded. The first transistor (Q3) is switched on and off by receiving a single-ended signal from the differential signal receiver. When the first transistor (Q3) is on, the power signal from the linear regulator is divided by the third resistor (R9) and the fourth resistor (R12) to make the voltage across the fourth resistor (R12) the first voltage. When the first transistor (Q3) is off, the voltage across the fourth resistor (R12) is the second voltage. The single-ended signal controls the switching on and off of the first transistor (Q3) and drives the output through the power supply signal. The single-ended signal is converted into a differential signal across the fourth resistor (R12). The differential signal is impedance matched by adjusting the resistance value of the fourth resistor (R12) and output from the output terminal (P4) after isolating the DC component through the fifth capacitor (C23).

6. The signal distributor according to claim 1, characterized in that, The signal source is an SPDIF signal source, which is connected to the isolation transformer module via an audio cable RCA. Each level conversion and impedance matching module is connected to the corresponding device under test via an audio cable RCA.

7. A test device based on a signal distributor, characterized in that, The testing apparatus includes a signal distributor as described in any one of claims 1 to 6.

8. The test apparatus based on a signal distributor according to claim 7, characterized in that, The testing device also includes an SPDIF signal source and multiple devices under test. The input of the signal distributor is connected to the SPDIF signal source, and the output of the signal distributor is connected to each device under test to perform testing on the device under test.

9. A test method based on a signal distributor, characterized in that, The test method uses the signal distributor as described in any one of claims 1 to 6 to convert one differential signal into multiple differential signals for output.

10. The test method according to claim 9, characterized in that, The step of converting one differential signal into multiple differential signals for output includes: Receive one SPDIF differential signal from an SPDIF source and perform DC isolation processing on the SPDIF differential signal; The SPDIF differential signal after isolation DC processing is converted into multiple single-ended signals, and each single-ended signal is converted into a corresponding differential signal. Each differential signal is input to the corresponding device under test for testing.

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