Cable

Abstract

A cable (1) comprises a first retimer (10a), a second retimer (10b), and coaxial transmission lines (20). The first retimer (10a) and the second retimer (10b) each have a differential-to-single-ended conversion unit (11) that receives input of a differential signal to output a single-ended signal, and a single-ended-to-differential conversion unit (12) that receives input of a single-ended signal to output a differential signal. The first retimer (10a) and the second retimer (10b) are connected through the coaxial transmission lines (20).

Description

cable

[0001] The present disclosure relates to cables.

[0002] Patent Document 1 discloses a technique for reducing the number of electric wires by using the ground shield of a coaxial line or an STP line as a signal line for low-speed communication.

[0003] U.S. Patent No. 9,076,575

[0004] In the technique disclosed in the above-mentioned Patent Document 1, the number of electric wires can be reduced to two in addition to the ground shield, but it is desired to further reduce the number of electric wires.

[0005] Therefore, the present disclosure provides a cable that can reduce the number of electric wires.

[0006] The cable according to the present disclosure comprises a first conversion unit, a second conversion unit, and a coaxial line, and the first conversion unit and the second conversion unit respectively have a differential-to-single conversion unit that receives a differential signal as input and outputs a single-ended signal, and a single-to-differential conversion unit that receives a single-ended signal as input and outputs a differential signal, and the first conversion unit and the second conversion unit are connected via the coaxial line.

[0007] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0008] According to a cable according to one aspect of the present disclosure, the number of wires can be reduced.

[0009] FIG. 1 is a configuration diagram showing an example of a cable according to an embodiment. FIG. 2 is a diagram showing an example of a layer structure of a coaxial line according to an embodiment. FIG. 3 is a diagram showing an example of a cross-sectional structure around a retimer according to an embodiment. FIG. 4 is a diagram for explaining power consumption when the coaxial line side is AC coupled. FIG. 5 is a diagram for explaining power consumption when the coaxial line side is DC coupled. FIG. 6 is a diagram schematically showing that the encoding method on the input side is different from the encoding method on the output side. FIG. 7 is a configuration diagram showing another example of a cable according to an embodiment. FIG. 8 is a configuration diagram showing an example of a differential to single conversion unit according to an embodiment. FIG. 9 is a configuration diagram showing an example of a single to differential conversion unit according to an embodiment. FIG. 10 is a configuration diagram showing another example of a differential to single conversion unit according to an embodiment. FIG. 11 is a circuit diagram showing an example of a differential to single conversion unit and a single to differential conversion unit according to an embodiment. FIG. 12 is a circuit diagram around a single to differential converter according to an embodiment.

[0010] A cable according to one aspect of the present disclosure comprises a first conversion unit, a second conversion unit, and a coaxial line, wherein the first conversion unit and the second conversion unit each have a differential-to-single conversion unit that receives a differential signal as input and outputs a single-ended signal, and a single-to-differential conversion unit that receives a single-ended signal as input and outputs a differential signal, and the first conversion unit and the second conversion unit are connected via the coaxial line.

[0011] According to this, the differential to single conversion unit included in one of the first conversion unit and the second conversion unit converts a differential signal to a single-ended signal and outputs it, and the single-to-differential conversion unit included in the other of the first conversion unit and the second conversion unit converts an input single-ended signal to a differential signal and outputs it. Therefore, it is sufficient that at least a single-ended signal is transmitted over the coaxial line connecting one differential to single conversion unit and one single-to-differential conversion unit, and it is possible to connect one differential to single conversion unit and one single-to-differential conversion unit with only one electric wire, thereby reducing the number of electric wires.

[0012] For example, the first conversion unit and the second conversion unit may be switchable so that either the differential to single conversion unit or the single to differential conversion unit is used, respectively.

[0013] This makes it possible to support cables with unidirectional signal direction, such as HDMI (registered trademark) (High Definition Multimedia Interface) cables or display port cables.

[0014] For example, the first conversion unit and the second conversion unit may each be DC coupled on the coaxial line side and AC coupled on the opposite side to the coaxial line.

[0015] According to this, since the coaxial line side is DC coupled, the current consumption can be made smaller than when the coaxial line side is AC coupled, and power consumption can be reduced.

[0016] For example, the first conversion unit and the second conversion unit may each be covered with a metal shield.

[0017] This makes it possible to suppress EMI (Electro Magnetic Interference) generated from the cable by the metal shield.

[0018] For example, an external shield covering the coaxial line may be connected to the metal shield and the ground of a substrate on which the first conversion unit or the second conversion unit is mounted.

[0019] This makes it possible to further suppress EMI generated from the cable.

[0020] For example, the differential to single conversion unit may have two output terminals capable of outputting a differential signal, and one of the two output terminals may be connected to a termination resistor to output a single-ended signal.

[0021] This allows a differential to single conversion unit that outputs a single-ended signal to be realized by connecting a termination resistor to one of two output terminals that can output a differential signal. For example, it is not necessary to prepare a dedicated product that outputs a single-ended signal, and a component that receives a differential signal and outputs a differential signal can be used as the differential to single conversion unit.

[0022] For example, the single-to-differential conversion unit may have two input terminals to which a differential signal can be input, and one of the two input terminals may be connected to a termination resistor to input a single-ended signal.

[0023] This allows a single-to-differential conversion unit to receive a single-ended signal by connecting a termination resistor to one of two input terminals that can receive a differential signal. For example, it is not necessary to prepare a dedicated component that receives a single-ended signal, and a component that receives a differential signal and outputs a differential signal can be used as the single-to-differential conversion unit.

[0024] For example, the termination resistor may be built into the first conversion unit or the second conversion unit.

[0025] According to this, by incorporating the termination resistor in advance into the first conversion unit or the second conversion unit, the number of parts can be reduced.

[0026] For example, the differential to single conversion unit may have a single-ended output unit that outputs a single-ended signal and a differential output unit that outputs a differential signal, and may be switchable so that either the single-ended output unit or the differential output unit is used.

[0027] According to this, by using the single-ended output section of the single-ended output section and the differential output section, a differential to single conversion section that outputs a single-ended signal can be realized. For example, it is not necessary to prepare a dedicated product that outputs a single-ended signal, and a component that can switch between outputting a single-ended signal and a differential signal can be used as the differential to single conversion section.

[0028] For example, the single-differential conversion unit may have a single-ended input unit to which a single-ended signal is input and a differential input unit to which a differential signal is input, and may be switchable so that either the single-ended input unit or the differential input unit is used.

[0029] According to this, by using the single-ended input section of the single-ended input section and the differential input section, it is possible to realize a single-to-differential conversion section to which a single-ended signal is input. For example, it is not necessary to prepare a dedicated product to which a single-ended signal is input, and a component that can switch between inputting a single-ended signal and a differential signal can be used as the single-to-differential conversion section.

[0030] For example, the differential to single conversion section may output a single-ended signal having a larger amplitude than the amplitude of the input differential signal.

[0031] According to this, the amplitude is increased when converting a differential signal into a single-ended signal, thereby ensuring the S / N ratio.

[0032] For example, the differential single conversion unit and the single differential conversion unit may each include a differential amplifier that receives a differential signal as input and outputs a first differential signal, a single differential converter that receives one of the differential signals as input and outputs a second differential signal, and a switch that receives the first differential signal and the second differential signal as input and switches between and outputs one of the first differential signal and the second differential signal.

[0033] With this, both the functions of the differential to single conversion unit and the functions of the single to differential conversion unit can be realized by a differential amplifier, a single to differential converter, and a switch, and by switching the signal output by the switch between the first differential signal and the second differential signal, it is possible to switch between the functions of the differential to single conversion unit and the functions of the single to differential conversion unit.

[0034] For example, the single-to-differential converter may receive a first input signal, which is one of the differential signals, and a second input signal, and an output terminal of a first output signal corresponding to the first input signal may be capacitively coupled to an input terminal of the second input signal.

[0035] According to this, by feeding back the first output signal to the second input signal via the capacitance, it is possible to prevent the amplitude of the second input signal from becoming smaller, and it is possible to ensure the S / N ratio.

[0036] For example, the second input signal may include a bias signal at a midpoint potential of the differential signal.

[0037] This requires a bias because the first output signal is fed back to the second input signal via capacitance, but since the second input signal includes a bias signal at the midpoint potential of the differential signal, the bias of the circuit can be ensured.

[0038] For example, a replica circuit identical to the circuit to which the first input signal is input may be connected to an output terminal of a second output signal corresponding to the second input signal.

[0039] This makes it possible to balance the load on the output terminal of the first output signal and the load on the output terminal of the second output signal, thereby improving the waveform of the output signal.

[0040] For example, when the single-to-differential conversion unit included in one of the first conversion unit and the second conversion unit detects an error in the input single-ended signal, it may notify the differential-to-single conversion unit included in the other of the first conversion unit and the second conversion unit to increase the amplitude of the single-ended signal to be output.

[0041] This allows the differential to single conversion unit to increase the amplitude of the output single-ended signal when an error is detected in the single-ended signal input to the single-differential conversion unit, thereby improving signal connectivity.

[0042] For example, the input-side encoding method and the output-side encoding method may be different in the differential to single conversion unit and the single to differential conversion unit. Specifically, the input-side encoding method in the differential to single conversion unit may be a binary encoding method and the output-side encoding method may be a multi-value encoding method of 3 or more, and the input-side encoding method in the single to differential conversion unit may be a multi-value encoding method of 3 or more, and the output-side encoding method may be a binary encoding method.

[0043] This allows multiple values ​​to be expressed in a single-ended signal, and the amount of information in a signal transmitted over one wire increases, allowing the number of wires to be further reduced accordingly.

[0044] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0045] The embodiments described below are all comprehensive or specific examples, and the numerical values, shapes, materials, components, arrangement and connection of the components, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0046] (Embodiment) A cable according to an embodiment will be described below.

[0047] FIG. 1 is a diagram showing an example of a cable 1 according to an embodiment.

[0048] The cable 1 includes a first retimer 10a, a second retimer 10b, and a coaxial line 20. The first retimer 10a is an example of a first conversion unit, and the second retimer 10b is an example of a second conversion unit. When a signal is transmitted at high speed, the waveform is disturbed due to attenuation of the signal amplitude and the influence of noise, but the first retimer 10a and the second retimer 10b compensate for the jitter, enabling high-speed signal transmission while maintaining the waveform.

[0049] The first retimer 10a and the second retimer 10b each have a differential to single conversion unit 11 and a single to differential conversion unit 12. For example, the first retimer 10a has a plurality of differential to single conversion units 11 and a plurality of single to differential conversion units 12, and the second retimer 10b has a plurality of differential to single conversion units 11 and a plurality of single to differential conversion units 12. The differential to single conversion unit 11 receives a differential signal and outputs a single-ended signal. The single-ended signal is input to the single-ended conversion unit 12 and outputs a differential signal.

[0050] The first retimer 10a and the second retimer 10b are connected via a coaxial line 20. Furthermore, for example, a connector is connected to each of the first retimer 10a and the second retimer 10b. The connector is, for example, a USB (Universal Serial Bus) connector. The differential to single conversion unit 11 converts a differential signal input from the connector into a single-ended signal and outputs it to the coaxial line 20. The single-ended to differential conversion unit 12 converts a single-ended signal input from the coaxial line 20 into a differential signal and outputs it to the connector.

[0051] In this way, the differential to single conversion unit 11 included in one of the first retimer 10 a and the second retimer 10 b converts a differential signal into a single-ended signal and outputs it, and the single-to-differential conversion unit 12 included in the other of the first retimer 10 a and the second retimer 10 b converts the input single-ended signal into a differential signal and outputs it. Therefore, it is sufficient that at least a single-ended signal is transmitted over the coaxial line 20 connecting one differential to single conversion unit 11 and one single-to-differential conversion unit 12, and it is possible to use only one electric wire to connect one differential to single conversion unit 11 and one single-to-differential conversion unit 12, thereby reducing the number of electric wires.

[0052] In the following description, when there is no need to distinguish between the first retimer 10a and the second retimer 10b, the first retimer 10a and the second retimer 10b will also be referred to as retimers 10. The first conversion unit and the second conversion unit are not limited to retimers, and may be redrivers or repeaters, etc. In other words, the first retimer 10a and the second retimer 10b may each be a redriver or a repeater.

[0053] Next, the structure of the coaxial line 20 will be described with reference to FIG.

[0054] FIG. 2 is a diagram showing an example of a layer structure of the coaxial line 20 according to the embodiment.

[0055] 2, the coaxial line 20 has, for example, a central conductor at its center, and an insulator, an outer shield, a copper foil, a wire identification coating, and an insulating coating arranged radially outward from the central conductor. Note that the layer structure shown in FIG. 2 is an example, and some components may not be provided, or additional components may be provided.

[0056] Next, the structure around the retimer 10 will be described with reference to FIG.

[0057] FIG. 3 is a diagram showing an example of a cross-sectional structure around the retimer 10 according to the embodiment.

[0058] For example, the retimer 10 is mounted on a substrate such as a paddle card, and a connector and a coaxial line 20 are connected to this substrate. This allows the retimer 10 to convert a differential signal input from the connector into a single-ended signal and output it to the coaxial line 20, or convert a single-ended signal input from the coaxial line 20 into a differential signal and output it to the connector.

[0059] 3, for example, the first retimer 10a and the second retimer 10b are each covered with a metal shield. The metal shield can suppress EMI generated from the cable 1. In addition, for example, the outer shield covering the coaxial line 20 is connected to the metal shield and to the ground (e.g., a ground pad) of the substrate on which the retimer 10 (the first retimer 10a or the second retimer 10b) is mounted. This can further suppress EMI generated from the cable 1.

[0060] For example, the first retimer 10a and the second retimer 10b may each be DC coupled on the coaxial line 20 side and AC coupled on the side opposite the coaxial line 20 (i.e., the connector side). By DC coupling on the coaxial line 20 side, current consumption can be made smaller than when the coaxial line 20 side is AC coupled, and power consumption can be reduced. This will be described using Figures 4A and 4B.

[0061] FIG. 4A is a diagram for explaining power consumption when the coaxial line 20 side is AC coupled.

[0062] FIG. 4B is a diagram for explaining power consumption when the coaxial line 20 side is DC coupled.

[0063] As shown in Fig. 4A, when the coaxial line 20 side is AC coupled, a current of I = 2V / R is required to pass a signal with an amplitude of voltage V from the current driver to the coaxial line 20. On the other hand, as shown in Fig. 4B, when the coaxial line 20 side is DC coupled, a current of I = V / R is required to pass a signal with an amplitude of voltage V from the voltage driver to the coaxial line 20. Therefore, when the coaxial line 20 side is DC coupled, the current consumption can be made smaller than when the coaxial line 20 side is AC coupled, and power consumption can be reduced.

[0064] For example, the differential to single converting unit 11 performs signal processing when converting a differential signal into a single-ended signal, and the single to differential converting unit 12 performs signal processing when converting a single-ended signal into a differential signal.

[0065] For example, the differential to single conversion unit 11 may perform signal processing so as to output a single-ended signal with a larger amplitude than the amplitude of the input differential signal. By increasing the amplitude when converting the differential signal into a single-ended signal, the S / N ratio can be ensured.

[0066] Furthermore, for example, the differential to single conversion unit 11 and the single to differential conversion unit 12 may perform encoding such that the encoding method on the input side differs from the encoding method on the output side in each of the differential to single conversion unit 11 and the single to differential conversion unit 12. For example, the encoding method on the input side (connector side) of the differential to single conversion unit 11 differs from the encoding method on the output side (coaxial line 20 side), and the encoding method on the input side (coaxial line 20 side) of the single to differential conversion unit 12 differs from the encoding method on the output side (connector side).

[0067] 5 is a diagram showing a differential single conversion unit 11, which is a schematic diagram showing that the encoding method on the input side is different from the encoding method on the output side.

[0068] 5, the encoding method on the input side (connector side) of the differential to single conversion unit 11 is a binary encoding method, and the encoding method on the output side (coaxial line 20 side) is a multi-value encoding method with three or more values. Also, although not shown, for example, the encoding method on the input side (coaxial line 20 side) of the single to differential conversion unit 12 is a multi-value encoding method with three or more values, and the encoding method on the output side (connector side) is a binary encoding method. This makes it possible to express multiple values ​​in a single-ended signal, increasing the amount of information in a signal transmitted over one electric wire, thereby further reducing the number of electric wires.

[0069] Furthermore, for example, when the single-to-differential conversion unit 12 of one of the first retimer 10a and the second retimer 10b detects an error in the input single-ended signal, it notifies the differential-to-single conversion unit 11 of the other of the first retimer 10a and the second retimer 10b to increase the amplitude of the output single-ended signal. For example, when the single-to-differential conversion unit 12 of the first retimer 10a detects an error in the input single-ended signal, it notifies the differential-to-single conversion unit 11 of the second retimer 10b to increase the amplitude of the output single-ended signal. For example, when the single-to-differential conversion unit 12 of the second retimer 10b detects an error in the input single-ended signal, it notifies the differential-to-single conversion unit 11 of the first retimer 10a ...

[0070] For example, the single-to-differential conversion unit 12 stores a pattern with a fixed order, such as a pattern indicated by a PRBS (Pseudo Random Binary Sequence), and detects an error when a signal with a pattern different from the stored pattern is input. In this way, when an error is detected in the single-ended signal input to the single-to-differential conversion unit 12, the differential-to-single conversion unit 11 can increase the amplitude of the single-ended signal to be output, thereby improving signal connectivity.

[0071] For example, the first re-timer 10 a and the second re-timer 10 b may be switchable so as to use either the differential to single converter 11 or the single to differential converter 12. This will be described with reference to FIG. 6 .

[0072] FIG. 6 is a diagram showing another example of the cable 1 according to the embodiment.

[0073] 6 , a differential to single converter 11 and a single to differential converter 12 are connected in parallel in one path, and switching is possible so that either the differential to single converter 11 or the single to differential converter 12 is used. For example, the first retimer 10a has a plurality of combinations of differential to single converters 11 and single to differential converters 12 connected in parallel, and the second retimer 10b has a plurality of combinations of differential to single converters 11 and single to differential converters 12 connected in parallel. For example, a register is rewritten by a switching signal, thereby switching so that either the differential to single converter 11 or the single to differential converter 12 is used. Note that the switching may also be performed by an external pin or the like.

[0074] For example, when the first re-timer 10a is switched so that only the differential single conversion unit 11 is used among the differential single conversion unit 11 and the single-differential conversion unit 12 for all combinations of the differential single conversion unit 11 and the single-differential conversion unit 12, the second re-timer 10b is switched so that only the single-differential conversion unit 12 is used among the differential single conversion unit 11 and the single-differential conversion unit 12 for all combinations of the differential single conversion unit 11 and the single-differential conversion unit 12. In this case, a signal is input to the first re-timer 10a, and a signal is output from the second re-timer 10b.

[0075] For example, when the first re-timer 10a is switched so that only the single-to-differential conversion unit 12 is used among the differential to single conversion units 11 and single-to-differential conversion units 12 for all combinations of the differential to single conversion units 11 and single-to-differential conversion units 12, the second re-timer 10b is switched so that only the differential to single conversion unit 11 is used among the differential to single conversion units 11 and single-to-differential conversion units 12 for all combinations of the differential to single conversion units 11 and single-to-differential conversion units 12. In this case, a signal is input to the second re-timer 10b, and a signal is output from the first re-timer 10a.

[0076] This makes it possible to support cables with unidirectional signals, such as HDMI cables or display port cables.

[0077] Next, methods for realizing the differential to single conversion unit 11 and the single to differential conversion unit 12 will be described with reference to Figures 7A to 9B. For example, the differential to single conversion unit 11 can be realized by methods described in Figures 7A, 8A, or 9A, and the single to differential conversion unit 12 can be realized by methods described in Figures 7B, 8B, or 9A.

[0078] FIG. 7A is a configuration diagram illustrating an example of the differential to single converting section 11 according to the embodiment.

[0079] 7A , the differential to single conversion unit 11 has two output terminals t1 and t2 capable of outputting differential signals, and one of the two output terminals t1 and t2, the output terminal t2, may be connected to a termination resistor to output a single-ended signal. In this way, by connecting a termination resistor to one of the two output terminals t1 and t2 capable of outputting differential signals, the differential to single conversion unit 11 that outputs a single-ended signal can be realized. For example, it is not necessary to prepare a dedicated component that outputs a single-ended signal; a component that receives a differential signal and outputs a differential signal can be used as the differential to single conversion unit 11.

[0080] FIG. 7B is a configuration diagram illustrating an example of the single-to-differential converting section 12 according to the embodiment.

[0081] 7B , the single-to-differential conversion unit 12 has two input terminals t11 and t12 that can input differential signals, and one of the two input terminals t11 and t12, the input terminal t12, may be connected to a termination resistor to input a single-ended signal. In this way, by connecting a termination resistor to one of the two input terminals t11 and t12 that can input a differential signal, a single-to-differential conversion unit 12 that inputs a single-ended signal can be realized. For example, it is not necessary to prepare a dedicated component that inputs a single-ended signal, and a component that inputs a differential signal and outputs a differential signal can be used as the single-to-differential conversion unit 12.

[0082] For example, the differential to single conversion unit 11 shown in FIG. 7A and the single to differential conversion unit 12 shown in FIG. 7B are the same component, and depending on how the termination resistor is connected, the component can be either the differential to single conversion unit 11 or the single to differential conversion unit 12.

[0083] The termination resistor may be built into the first retimer 10a or the second retimer 10b. For example, the termination resistor connected to the differential to single conversion unit 11 or the single to differential conversion unit 12 of the first retimer 10a may be built into the first retimer 10a, and the termination resistor connected to the differential to single conversion unit 11 or the single to differential conversion unit 12 of the second retimer 10b may be built into the second retimer 10b. By building the termination resistor into the first retimer 10a or the second retimer 10b in advance, the number of components can be reduced.

[0084] FIG. 8A is a configuration diagram showing another example of the differential single converting section 11 according to the embodiment.

[0085] 8A, the differential to single conversion section 11 may have a single-ended output section 11a that outputs a single-ended signal and a differential output section 11b that outputs a differential signal, and may be switchable so that either the single-ended output section 11a or the differential output section 11b is used. For example, a register is rewritten by a switching signal, thereby switching so that either the single-ended output section 11a or the differential output section 11b is used. Note that the switching may be performed by an external pin or the like.

[0086] Of the single-ended output unit 11a and the differential output unit 11b, the single-ended output unit 11a is used to realize the differential to single conversion unit 11 that outputs a single-ended signal. For example, it is not necessary to prepare a dedicated component that outputs a single-ended signal, and a component that can switch between outputting a single-ended signal and a differential signal can be used as the differential to single conversion unit 11.

[0087] FIG. 8B is a configuration diagram showing another example of the single-to-differential converting section 12 according to the embodiment.

[0088] 8B , the single-to-differential conversion unit 12 may have a single-to-differential input unit 12a to which a single-to-differential signal is input and a differential input unit 12b to which a differential signal is input, and may be switchable so that either the single-to-differential input unit 12a or the differential input unit 12b is used. For example, a register is rewritten by a switching signal, thereby switching between the single-to-differential input unit 12a and the differential input unit 12b. Note that the switching may be performed by an external pin or the like.

[0089] Of the single-ended input section 12a and the differential input section 12b, the single-ended input section 12a is used to realize the single-differential conversion section 12 to which a single-ended signal is input. For example, it is not necessary to prepare a dedicated component to which a single-ended signal is input, and a component that can switch between inputting a single-ended signal and a differential signal can be used as the single-differential conversion section 12.

[0090] For example, the differential to single conversion unit 11 and the single to differential conversion unit 12 can be realized by components having a single-ended output unit 11a, a differential output unit 11b, and a single-ended input unit 12a and a differential input unit 12b. For example, by switching to use the single-ended output unit 11a and the differential input unit 12b, the components can be used as the differential to single conversion unit 11. Furthermore, by switching to use the differential output unit 11b and the single-ended input unit 12a, the components can be used as the single to differential conversion unit 12.

[0091] FIG. 9A is a circuit diagram illustrating an example of the differential-to-single converting section 11 and the single-to-differential converting section 12 according to the embodiment.

[0092] The differential single conversion unit 11 and the single differential conversion unit 12 each include a differential amplifier 31, a single differential converter 32, and a switch 33. The differential amplifier 31 receives a differential signal as input and outputs a first differential signal. The single differential converter 32 receives one of the differential signals as input and outputs a second differential signal. Specifically, the single differential converter 32 receives a first input signal and a second input signal, which are one of the differential signals. The switch 33 receives the first differential signal and the second differential signal as input and switches between and outputs one of the first differential signal and the second differential signal.

[0093] As a result, both the functions of the differential to single conversion unit 11 and the functions of the single to differential conversion unit 12 can be realized by the differential amplifier 31, the single to differential converter 32, and the switch 33, and by switching the signal output by the switch 33 between the first differential signal and the second differential signal, it is possible to switch between the functions of the differential to single conversion unit 11 and the functions of the single to differential conversion unit 12.

[0094] For example, the signal output by the switch 33 is switched to the first differential signal, thereby realizing the differential to single conversion unit 11. At this time, one signal of the first differential signal output from the switch 33 is used as a single-ended signal.

[0095] For example, the single-to-differential converting section 12 can be realized by switching the output signal to the second differential signal by the switch 33 .

[0096] Here, the peripheral circuitry of the single-to-differential converter 32 will be described with reference to FIG. 9B.

[0097] FIG. 9B is a circuit diagram of the area surrounding the single-to-differential converter 32 according to the embodiment, and is a circuit diagram of the portion surrounded by the dashed line in FIG. 9A.

[0098] 9B , the single-to-differential converter 32 is composed of transistors Tr1 and Tr2, etc. A first input signal is input to the gate of the transistor Tr1, and a first output signal corresponding to the first input signal is output from an output terminal (output terminal t22 described later) connected to the drain of the transistor Tr1. A second input signal is input to the gate of the transistor Tr2, and a second output signal corresponding to the second input signal is output from an output terminal (output terminal t23 described later) connected to the drain of the transistor Tr2.

[0099] The output terminal of the first output signal and the input terminal of the second input signal are coupled by a capacitor C1. As shown in FIG. 9A , the output terminal of the first output signal is the output terminal t22 of the single-ended to differential converter 32, which is connected to the drain of the transistor Tr1 within the single-ended to differential converter 32. As shown in FIG. 9A , the input terminal of the second input signal is the input terminal t21 of the single-ended to differential converter 32, which is connected to the gate of the transistor Tr2 within the single-ended to differential converter 32.

[0100] In this way, the first output signal is fed back to the second input signal via the capacitor C1, and the inverted signal is input as the second input signal, thereby ensuring the S / N ratio.

[0101] For example, the second input signal includes a bias signal at an intermediate potential of the differential signals. The bias signal is generated by a bias circuit 41. A bias is required because the first output signal is fed back to the second input signal via the capacitance C1, but the bias of the circuit can be ensured because the second input signal includes a bias signal at an intermediate potential of the differential signals.

[0102] For example, a replica circuit 42, which is the same as the circuit to which the first input signal is input, is connected to the output terminal of the second output signal. As shown in FIG. 9A , the output terminal of the second output signal is output terminal t23 of the single-ended to differential converter 32, and is connected to the drain of transistor Tr2 within the single-ended to differential converter 32. The replica circuit 42 includes a transistor Tr3, a resistor R2, and a current source A2, which are the same as the circuit to which the first input signal is input (transistor Tr1, resistor R1, and current source A1). The replica circuit 42 also includes a capacitor C2 connected between the drain of transistor Tr2 and the gate of transistor Tr3.

[0103] As a result, the output terminal of the first output signal is connected to the resistor R2, transistor Tr3, and current source A2 of the replica circuit 42 via the capacitor C1, and the output terminal of the second output signal is connected to the resistor R2, transistor Tr3, and current source A2 of the replica circuit 42 via the capacitor C2. In other words, it is possible to balance the load on the output terminal of the first output signal and the load on the output terminal of the second output signal, thereby improving the waveform of the output signal.

[0104] As described above, in the cable 1, the differential to single conversion unit 11 included in one of the first retimer 10 a and the second retimer 10 b converts a differential signal into a single-ended signal and outputs it, and the single to differential conversion unit 12 included in the other of the first retimer 10 a and the second retimer 10 b converts an input single-ended signal into a differential signal and outputs it. Therefore, it is sufficient that at least a single-ended signal is transmitted over the coaxial line 20 connecting one differential to single conversion unit 11 and one single-differential conversion unit 12, and it is possible to use only one electric wire to connect one differential to single conversion unit 11 and one single-differential conversion unit 12, thereby reducing the number of electric wires.

[0105] While the cable 1 according to one or more aspects of the present disclosure has been described above based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the spirit of the present disclosure, various modifications conceivable by a person skilled in the art to each embodiment and configurations constructed by combining components of different embodiments may also be included within the scope of one or more aspects of the present disclosure.

[0106] For example, in the above embodiment, the first retimer 10a and the second retimer 10b are each covered with a metal shield, but they do not necessarily have to be covered with a metal shield.

[0107] For example, in the above embodiment, an example was described in which the external shield covering the coaxial line 20 is connected to the metal shield and the ground of the substrate on which the first retimer 10a and the second retimer 10b are mounted, but it does not have to be connected to these.

[0108] For example, in the above embodiment, the differential to single converting section 11 performs signal processing when converting a differential signal into a single-ended signal, but signal processing does not have to be performed.

[0109] For example, in the above embodiment, the single-to-differential converting section 12 performs signal processing when converting a single-ended signal into a differential signal, but signal processing may not be performed.

[0110] For example, in the above embodiment, an example has been described in which, when an error is detected in the input single-ended signal, the single-to-differential conversion unit 12 of one of the first retimer 10a and the second retimer 10b notifies the differential-to-single conversion unit 11 of the other of the first retimer 10a and the second retimer 10b to increase the amplitude of the output single-ended signal; however, such notification does not have to be given.

[0111] The present disclosure is applicable to cables equipped with retimers and the like.

[0112] REFERENCE SIGNS LIST 1 Cable 10 Retimer 10a First retimer 10b Second retimer 11 Differential to single conversion section 11a Single-ended output section 11b Differential output section 12 Single-ended to differential conversion section 12a Single-ended input section 12b Differential input section 20 Coaxial line 31 Differential amplifier 32 Single-ended to differential converter 33 Switch 41 Bias circuit 42 Replica circuit A1, A2 Current source C1, C2 Capacitance R1, R2 Resistor t1, t2, t22, t23 Output terminal t11, t12, t21 Input terminal Tr1, Tr2, Tr3 Transistor

Claims

1. A first conversion unit; A second conversion unit; A coaxial line, The first conversion unit and the second conversion unit each a differential to single conversion unit that receives a differential signal and outputs a single-ended signal; a single-to-differential conversion unit that receives a single-ended signal and outputs a differential signal; The first conversion unit and the second conversion unit are connected via the coaxial line. cable.

2. The first conversion unit and the second conversion unit are each switchable so that either the differential to single conversion unit or the single to differential conversion unit is used.

2. The cable of claim 1.

3. The first conversion unit and the second conversion unit are DC-coupled on the coaxial line side and AC-coupled on the opposite side to the coaxial line.

2. The cable of claim 1.

4. The first conversion unit and the second conversion unit are each covered with a metal shield.

2. The cable of claim 1.

5. An outer shield covering the coaxial line is connected to the metal shield and to the ground of a substrate on which the first conversion unit or the second conversion unit is mounted.

5. The cable of claim 4.

6. The differential single conversion unit has two output terminals capable of outputting a differential signal, and outputs a single-ended signal by connecting one of the two output terminals to a termination resistor.

2. The cable of claim 1.

7. The single-to-differential conversion unit has two input terminals to which a differential signal can be input, and one of the two input terminals is connected to a termination resistor to input a single-ended signal.

2. The cable of claim 1.

8. The termination resistor is built into the first conversion unit or the second conversion unit.

7. The cable of claim 6.

9. The differential to single conversion section has a single-end output section that outputs a single-end signal and a differential output section that outputs a differential signal, and is switchable so that either the single-end output section or the differential output section is used.

2. The cable of claim 1.

10. The single-to-differential conversion unit has a single-end input unit to which a single-end signal is input and a differential input unit to which a differential signal is input, and is switchable so that either the single-end input unit or the differential input unit is used.

2. The cable of claim 1.

11. The differential to single conversion unit outputs a single-ended signal having a larger amplitude than the amplitude of the input differential signal.

2. The cable of claim 1.

12. The differential to single conversion unit and the single to differential conversion unit each include a differential amplifier that receives a differential signal and outputs a first differential signal; a single-to-differential converter that receives one of the differential signals and outputs a second differential signal; a switch to which the first differential signal and the second differential signal are input and which switches and outputs one of the first differential signal and the second differential signal.

2. The cable of claim 1.

13. The single-to-differential converter receives a first input signal, which is one of the differential signals, and a second input signal, and an output terminal of a first output signal corresponding to the first input signal and an input terminal of the second input signal are capacitively coupled to each other.

13. The cable of claim 12.

14. The second input signal includes a bias signal at a midpoint potential of the differential signals.

14. The cable of claim 13.

15. A replica circuit identical to the circuit to which the first input signal is input is connected to an output terminal of a second output signal corresponding to the second input signal.

14. The cable of claim 13.

16. When an error is detected in an input single-ended signal, the single-to-differential conversion unit included in one of the first conversion unit and the second conversion unit notifies the differential-to-single conversion unit included in the other of the first conversion unit and the second conversion unit to increase an amplitude of the single-ended signal to be output.

2. The cable of claim 1.

17. The input-side encoding method and the output-side encoding method in each of the differential to single conversion unit and the single to differential conversion unit are different. A cable according to any one of the preceding claims.

18. an input-side encoding method in the differential single conversion unit is a binary encoding method, and an output-side encoding method is a multi-value encoding method having 3 or more values, The encoding method on the input side of the single-to-differential conversion unit is a multi-value encoding method of 3 or more values, and the encoding method on the output side is a binary encoding method.

18. The cable of claim 17.