COMMUNICATION SYSTEM

Abstract

The communication system comprises a push-pull transmitter circuit (2) which includes a reflection signal attenuation circuit (10) configured to keep the reflection signals outside the amplitude direction of the communication signals to prevent contamination. The reflection signal attenuation circuit (10) comprises a first and a second rectifier element (D1 and D2) connected in series with a high-side driver element and a low-side driver element (Q1 and Q2), respectively, to prevent the reflection signals from flowing back from the communication signals to a power supply side, and a first and a second voltage limiting element (ZD1 and ZD2) connected in series with the high-side driver element and the low-side driver element, respectively.The low-side driver element (Q1 and Q2) is connected in parallel to provide limiting voltages approximately equal to 1.5 to 3 times the upper or lower limits for a HIGH level voltage of the communication signals (to add or subtract) when the reflection signals are passed through the communication signals.

Description

CROSS-REFERENCE TO RELATED REGISTRATION

[0001] The present application is based on and claims priority in accordance with the Paris Convention of Japanese patent application No. 2024-177344, filed on October 9, 2024, the entire disclosure of which is incorporated herein by reference as part of this application. BACKGROUND OF THE INVENTION [Area of ​​Invention]

[0002] The present invention relates to a communication system that attenuates reflection signals that may occur on a transmission line over which communication signals are transmitted. (Description of the state of the art)

[0003] In communication systems that use an electrical line to transmit communication signals, it is generally necessary for the impedance of the transmitter, receiver, and the electrical line to match. With a transmission line that has an incorrect impedance, there is a risk that reflection signals, caused by the mismatch, will contaminate the communication signals. Fig. Figure 7 shows a transmitted waveform, a received waveform containing reflection waveforms, and a binarized result of the received waveform.

[0004] Consider an example situation where the impedance Zt of the transmitter and the electrical line is 50 Ω each, and the impedance Zr of the receiver is 1000 Ω. Assuming that the symbol At represents the signal amplitude on the transmitter side, the reflection coefficient (or reflection amplitude) Γ n given by equation (1): Γn=At×{(Zr−Zt)÷(Zr+Zt)}n

[0005] The initial reflection amplitude (with n = 1) would then be equal to: Γ1=At×{(1000−50)÷(1000+50)}1=0.90 At

[0006] Thus, a reflection waveform with 0.90 times the signal amplitude At would appear on the transmitter side.

[0007] A reflection time t, which is proportional to a line length L, is given by: t(s)=2L÷υ where u denotes the transmission speed of signals on the electrical line. For an electrical line using a typical coaxial or twisted-pair cable (where u is approximately 2 × 10 8 (m / s corresponds to), with an example length L of 100 m, the reflection time t would be: t=2×100÷(2×108)=1×10−6=1(μs)

[0008] If the reflection amplitude Γ1 is very high and a received waveform like in Fig. If the voltage drops below a binarization voltage threshold Vt, this situation is analogous to the signals demodulated on the receiver side being contaminated with noise, which affects the quality of the communication.

[0009] In the Fig. 8 and Fig. Figure 9 shows conventional push-pull transmitter circuits featuring a communication signal driver transistor Q11 as the high-side driver element and a communication signal driver transistor Q12 as the low-side driver element. A high-side driver signal turns on Q11 to drive the communication signals to a HIGH level, while a low-side driver signal turns on Q12 to drive the communication signals to a LOW level. Both Q11 and Q12 are turned off when a non-activated state with high impedance is desired.

[0010] A rectifier element (or diode) D11 is connected in parallel with transistor Q11 to protect transistor Q12 from voltages exceeding its reverse bias voltage when a reflection signal current flows through the positive communication signal side. This is achieved by allowing the reflection signal current to pass through to the positive supply side, thus limiting the maximum voltage on the positive communication signal side to the positive supply voltage plus the forward voltage of diode D11. A diode D12 is connected in parallel with transistor Q12 to prevent transistor Q11 from exceeding its own reverse bias voltage when a reflection signal current flows through the positive communication signal side. This is achieved by allowing the reflection signal current to pass through to the negative communication signal side.The minimum voltage on the positive communication signal side is limited to the voltage of the negative supply minus the forward voltage of diode D12.

[0011] Capacitor C11 is a bypass capacitor that provides a reduced high-frequency impedance between the positive supply side and the negative supply side, as well as between the positive supply side and the negative communication signal side. It also conducts the electrical current of a reflection signal, which flows in via the positive communication signal side during the high-side drive periods, from the positive communication signal side, through the positive supply side, capacitor C11, and the negative supply side, to the negative communication signal side.

[0012] Point (20) in Fig. Figure 7 shows a reflection waveform at the beginning of a high-side drive period. At this point, the electrical current of the reflection signal flows through the transmitter circuit of Fig. 8 along path (A). That is, the current flows from the negative communication signal side to the positive communication signal side through capacitor C11 and transistor Q11. After the reflection time t has elapsed, the reflection signal reverses, as shown at point (21) on the receiver side, so that the current of the reflection signal through the transmitter circuit of Fig. 8 along path (B). That is, the current flows from the positive communication signal side to the negative communication signal side through diode D11 and capacitor C11. The reflected signal therefore oscillates with an amplitude Γ1 around the voltage of the positive supply.

[0013] Point (22) in Fig. Figure 7 shows a reflection signal at the beginning of a low-side drive period. At this point, the electrical current of the reflection signal flows through the transmitter circuit of Fig. 9 along the path (B). After the reflection time t has elapsed, the reflection signal flips, as shown at point (23) on the receiver side, so that the current of the reflection signal through the transmitter circuit of Fig. 9 flows along path (B). The reflection signal therefore oscillates with an amplitude Γ1 around the voltage of the negative supply.

[0014] Accordingly, the reflection waveform could fall below the binarization voltage threshold Vt at point (21) and at point (23) in Fig. 7 rise above the binarization voltage threshold Vt, such that the reflected signal crosses the binarization voltage threshold Vt at points (21) and (23), resulting in discontinuities in the binarized result of the received waveform. This noise contamination can lead to binarized results with values ​​that differ from the original communication signals.

[0015] Various countermeasures against such contamination by reflection signals are known from the past. For example, it is known to perform binarization in anticipation of the presence of a reflection waveform at the time of demodulation of the received signals (e.g., WO2008 / 038388A1) or to adjust the transmitter impedance to attenuate a reflection waveform (e.g., JP2009-296568A).

[0016] Among other things, it is also known to provide a receiver circuit that has a function for correcting (or shaping) a reflection waveform for correct demodulation when reflection waveforms are present (e.g., JP2011-239091A), or to select an electrical line of a prescribed length that reduces a reflection waveform (or ringing) that occurs on branch lines (e.g., JP2016-051968A). These earlier technologies aim to improve communication quality by using a transmission line in such a way as to attenuate a reflection waveform produced by a mismatched impedance, or by correcting a reflection waveform on the receiver side. OVERVIEW OF THE INVENTION

[0017] However, these existing countermeasures against reflection waves require a complex circuit configuration or a change in the circuit if a different electrical conductor length is used, which may complicate the circuit designs.

[0018] It is an object of the present invention to overcome the aforementioned problems by providing a communication system with a simple circuit configuration capable of easily attenuating reflection waves without requiring circuit modifications when a different electrical conductor length is used. To achieve this object, the present invention provides a communication system comprising a push-pull transmitter circuit and a receiver circuit. The push-pull transmitter circuit includes a high-side driver element and a low-side driver element for transmitting communication signals with HIGH and LOW level binary values.The push-pull transmitter circuit also includes a reflection signal attenuation circuit configured to attenuate the effect of reflection signals occurring on a transmission line of the communication system on the communication signals. This is achieved by biasing the reflection signals away from the amplitude direction of the communication signals to prevent contamination. The receiver circuit is configured to receive and distinguish between HIGH and LOW levels of the communication signals using a binarization voltage threshold. The reflection signal attenuation circuit includes a first and a second rectifier element, connected to the high-side driver element, respectively.a first and a second voltage limiting element connected in series with the low-side driver element and configured to prevent reflection signals from the communication signals from flowing back to a power supply side; and a first and a second voltage limiting element connected in parallel with the high-side driver element and the low-side driver element respectively, configured to add to or subtract limiting voltages approximately equal to 1.5 to 3 times the upper or lower limits (e.g., voltages) for a HIGH-level voltage of the communication signals when reflection signals from the communication signals are passed through them.

[0019] The limiting voltages added or subtracted by the first and second voltage limiting elements are chosen to be approximately 1.5 to 3 times the limits to ensure that the communication signals are not contaminated by the reflection signals, or to take into account the blocking voltages of the driver elements.

[0020] According to this configuration, the reflection signal attenuation circuit of the push-pull transmitter circuit has a first and a second rectifier element connected in series with the high-side driver element and the low-side driver element, respectively, and a first and a second voltage limiting element connected in parallel with the high-side driver element and the low-side driver element, respectively, to add or subtract limiting voltages approximately equal to 1.5 to 3 times the upper or lower limits for a HIGH-level voltage. This biases the reflection signals out of amplitude direction with the communication signals to prevent the amplitude of the communication signals from being affected by the reflection signals, thus preventing the reflection signals from exceeding the binarization voltage threshold and contaminating the communication signals.In this way, the attenuation of reflection signals can be easily achieved with a simple circuit configuration, without having to change the circuit when a different electrical line length is used, thus making long-distance transmission and bus branching easily possible.

[0021] Furthermore, the reflection signal attenuation circuit can be configured such that: the first rectifier element, connected in series with the high-side driver element, prevents positive electrical current of the reflection signals from flowing back from the communication signals to a positive supply side; the second voltage limiting element, connected in parallel with the low-side driver element, adds a cap voltage approximately 1.5 to 3 times the positive upper limit for the HIGH-level voltage when the positive electrical current of the communication signals is passed through; the second rectifier element, connected in series with an output of the low-side driver element, prevents negative electrical current of the reflection signals from flowing back from the communication signals to a negative supply side;and the first voltage limiting element, connected in parallel to the high-side driver element, subtracts a limiting voltage approximately 1.5 to 3 times a negative lower limit for the HIGH level voltage when the negative electrical current of the reflection signals is passed through by the communication signals.

[0022] In this way, the attenuation of reflection signals can be easily achieved with a simple circuit configuration, without having to change the circuit when a different electrical conductor length is used.

[0023] Preferably, the first and second voltage limiting elements are configured to add or subtract limiting voltages approximately twice the upper and lower limits, respectively, for the HIGH-level voltage. Therefore, attenuation of reflection signals can be easily achieved with a much simpler circuit configuration.

[0024] It should be noted that the preceding configurations for the communication system can be refined in some parts to obtain the following configurations (A) to (C). It is therefore understood that the following configurations do not have a scope of protection or technical application that differs substantially from that of the preceding configurations: (A) A communication system comprising the following: A push-pull transmitter circuit comprising a high-side driver element and a low-side driver element for transmitting communication signals with HIGH and LOW level binary values, wherein the transmitter circuit further a reflection signal attenuation circuit or a reflection signal rectifier circuit configured to attenuate the effect of reflection signals occurring on a transmission line of the communication system on the communication signals by biasing the reflection signals away from an amplitude direction of the communication signals to prevent their contamination; and a receiver circuit configured to receive and differentiate HIGH and LOW levels of communication signals using a binarization voltage threshold, the reflection signal attenuation circuit features: a first and a second rectifier element connected in series with the high-side driver element and the low-side driver element, respectively, and configured to prevent reflection signals from the communication signals from flowing back to a power supply side; and First and second voltage limiting elements, connected in parallel to the high-side driver element and the low-side driver element respectively, and configured to keep the upper or lower limits of a waveform of the reflection signals on the communication signals within limiting voltages approximately 1.5 to 3 times the transmission amplitude At of the communication signals when the reflection signals are driven by the communication signals they will be led through; (B) A communication system according to the preceding configuration (A) wherein the reflection signal attenuation circuit is configured such that: The first rectifier element, which is connected in series with the high-side driver element, prevents positive electrical current of the reflection signals from flowing back from the communication signals to a positive supply side; The second voltage limiting element, connected in parallel to the low-side driver element, maintains a positive upper limit of the waveform of the reflection signals within a limiting voltage that is approximately 1.5 to 3 times the transmission amplitude At when the positive electric current from the communication signals passes through; The second rectifier element, which is connected in series with an output of the low-side driver element, prevents electrical current from the reflection signals flowing back from the communication signals to a negative supply side; and The first voltage limiting element, connected in parallel to the high-side driver element, maintains a negative lower limit of the waveform of the reflection signals within a limiting voltage approximately equal to 1.5 to 3 times the transmission amplitude At when the negative electrical current of the reflection signals passes through from the communication signals; (C) A communication system according to one of the preceding configurations (A) or (B) wherein the first and second voltage limiting elements are configured to maintain within the limiting voltages approximately twice the transmission amplitude At.

[0025] All combinations of at least two features disclosed in the claims and / or the specification and / or the drawings should also be interpreted as encompassed by the present invention. In particular, all combinations of two or more of the claims should be interpreted as encompassed by the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will become clearer from the following description of a preferred embodiment with reference to the accompanying drawings. However, the embodiments and the drawings serve only for illustrative and explanatory purposes and are not to be used to limit the scope of the present invention, which is limited by the accompanying claims. In the accompanying drawings, the same reference numerals are assigned to and identify the same parts in the various figures. 0022 Fig. Figure 1 shows a circuit diagram of a transmitter circuit of a communication system according to an embodiment of the present invention; Fig. 2 is a circuit diagram of a receiver circuit of the communication system; Fig. Figure 3 shows how reflection signals flow during the high-side drive periods of the transmitter circuit; Fig. Figure 4 shows how reflection signals flow during the low-side drive periods of the transmitter circuit; Fig. Figure 5 shows a waveform on the receiver side; Fig. Figure 6 shows a waveform on the transmitter side; Fig. Figure 7 shows a transmitted waveform, a received waveform containing reflection waveforms, and a binarized result of the received waveform according to a conventional example; Fig. Figure 8 shows how reflection signals flow during the high-side drive periods of the conventional transmitter circuit; and Fig. Figure 9 shows how reflection signals flow during the low-side drive periods of the conventional transmitter circuit. DESCRIPTION OF EXECUTION FORMS

[0027] The following is a description of preferred embodiments of the present disclosure with reference to the drawings. Fig. Figure 1 shows a transmitter circuit 2 of a communication system 1 according to an embodiment of the present invention. The transmitter circuit 2 has the form of a push-pull output circuit, which includes a high-side driver element (e.g., a communication signal driver PNP transistor Q1) and a low-side driver element (e.g., a communication signal driver NPN transistor Q2) to transmit communication signals with HIGH and LOW level binary values.

[0028] To drive a communication signal at a HIGH level, a high-side driver signal 3 is applied to base B of transistor Q1 to turn it on. To drive a communication signal at a LOW level, a low-side driver signal 4 is applied to base B of transistor Q2 to turn it on. Both transistor Q1 and transistor Q2 are turned off when a non-activated state with high impedance is desired.

[0029] The transmitter circuit 2 includes a reflection signal attenuation circuit 10, which is configured to attenuate the effect of reflection waves occurring on a transmission line of the communication system 1 on the communication signals. The reflection signal attenuation circuit 10 includes a first and a second voltage limiting element (e.g., the Zener diodes ZD1 and ZD2) as well as a first and a second rectifier element (e.g., the rectifier diodes D1 and D2).

[0030] A positive supply voltage 7 is connected to the junction between the emitter E of transistor Q1 and the cathode K of Zener diode ZD1. A negative supply voltage 8 is connected to the junction between the emitter E of transistor Q2 and an anode A of Zener diode ZD2. A positive communication signal 5 is output via the junction between a cathode K of rectifier diode D1 and an anode A of rectifier diode D2. A negative communication signal 6 is output via the junction between the emitter E of transistor Q2 and an anode A of Zener diode ZD2.

[0031] The high-side driver rectifier diode D1 is connected in series with the junction between a collector C of transistor Q1 and an anode A of Zener diode ZD1 to prevent positive electrical current from the reflection signals entering via the positive communication signal side 5 from flowing back to the positive power supply side 7. The low-side driver rectifier diode D2 is connected in series with the junction between a collector C of transistor Q2 and a cathode K of Zener diode ZD2 to prevent negative electrical current from the reflection signals entering via the positive communication signal side 5 from flowing back to the positive power supply side 8.

[0032] Zener diode ZD1 is connected in parallel with transistor Q1 for voltage subtraction when negative current from reflection signals flows across the positive communication signal 5, so that the voltage of the positive supply 7 minus the voltage across Zener diode ZD1 is applied to the positive communication signal 5. Zener diode ZD2 is connected in parallel with transistor Q2 for voltage addition when positive current from reflection signals flows across the positive communication signal 5, so that the voltage of the negative supply 8 minus the voltage across Zener diode ZD2 is applied to the positive communication signal 5.

[0033] Here, Zener diodes ZD1 and ZD2 are configured to provide limiting voltages or to add or subtract a breakdown voltage from the upper or lower limit of a HIGH-level voltage of the communication signals, where the breakdown voltage is a limiting voltage that is preferably about 1.5 to 3 times the limit (e.g., voltage). In other words, Zener diodes ZD1 and ZD2 are configured to keep the voltages within approximately 1.5 to 3 times the upper or lower limit of the HIGH-level voltage. Preferably, they are configured to provide limiting voltages that are approximately twice the upper or lower limit of the HIGH-level voltage. Approximately 1.5 to 3 times the limits for Zener diodes ZD1 and ZD2 are chosen to ensure that the communication signals are not contaminated by reflection signals.to take into account the blocking voltages of the driver elements.

[0034] Capacitor C1 is a bypass capacitor that provides a reduced high-frequency impedance between the positive supply side 7 and the negative supply side 8, as well as between the positive supply side 7 and the negative communication signal side 6. It also conducts the electrical current of reflection signals, which enters via the positive communication signal side 5, from the negative communication signal side 6, through the negative supply side 8, capacitor C1, and the positive supply side 7, to the positive communication signal side 5. 0031 Fig. Figure 2 shows a receiver circuit 20 configured to receive positive communication signals 5 and negative communication signals 6 transmitted by the transmitter circuit 2. A Zener diode ZD3 defines a binarization voltage threshold Vt. Resistors R1 and R2 determine a base current flowing to a transistor Q3. An emitter of transistor Q3 is connected to a negative supply voltage 23, and a resistor R3, coupled to a positive supply voltage 22, is connected to a collector of transistor Q3 to generate a voltage with a collector current and provide a received signal 21.

[0035] Fig. Figure 3 shows how the electrical current of the reflection signals flows during the high-side drive periods (when the communication signals are at a HIGH level), and Fig. Figure 4 shows how the electrical current of the reflection signals flows during the low-side drive periods (when the communication signals are at a LOW level). During high-side drive periods, negative electrical current of the reflection signals flows through the transmitter circuit 2. Fig. 3 along the path (A). That is, the negative electric current flows from the negative communication signal side 6 to the positive communication signal side 5 through the capacitor C1, the transistor Q1, and the rectifier diode D1. After the reflection time t has elapsed, the reflection signal flips on the receiver side, so that positive electric current of the reflection signals in Fig. 3 flows along path (B). That is, the positive electric current flows from the positive communication signal side 5 to the negative communication signal side 6 through the rectifier diode D2 and the Zener diode ZD2.

[0036] During low-side drive periods, positive electrical current of the reflection signals flows through transmitter circuit 2. Fig. 4 along the path (B). That is, the positive electric current flows from the positive communication signal side 5 to the negative communication signal side 6 through the rectifier diode D2 and the transistor Q2. After the reflection time t has elapsed, the reflection signals on the receiver side reverse, so that negative electric current of the reflection signals in Fig. 4 flows along the path (A). That is, the negative electric current flows from the negative communication signal side 6 to the positive communication signal side 5 through the capacitor C1, the Zener diode ZD1 and the rectifier diode D1.

[0037] According to the present invention, the reflection signal attenuation circuit 10 of the push-pull transmitter circuit 2 prevents Fig. 1. that reflection signals endanger the amplitude of the communication signals, with a simple circuit configuration that uses rectifier diodes D1 and D2 connected in series with the high-side and low-side driver elements Q1 and Q2 respectively as rectifier elements, and with a simple circuit configuration that has Zener diodes ZD1 and ZD2 connected in parallel with the high-side and low-side driver elements Q1 and Q2 respectively to add and subtract voltages, and that breakdown voltages (limiting voltages) of the same are set to approximately 1.5 to 3 times the transmission amplitude At of the communication signals.

[0038] Fig. Figure 5 shows a waveform on the receiver side according to transmitter circuit 2. Fig. 3. Points (1) and (3) in Fig. 5 have a reflection amplitude Γ1 (with n = 1) determined according to equation (1) and a reflection time t determined according to equation (2). Fig. Figure 6 shows a waveform on the transmitter side according to transmitter circuit 2 of Fig. 3. The negative electric current of the reflection signals flows at point (11) in Fig. 6 during a high-side approach period over the path (A) in Fig. 3 and generates a voltage equal to the positive supply voltage 7 plus the forward voltage of diode D1. At point (12), the reflection signals from the receiver side arrive after the reflection time t according to equation (2), and a positive electric current flows via path (B) into Fig. 3, which adds the reflection amplitude Γ2 (with n = 2) according to equation (1) to the transmission amplitude At of the voltage of a positive communication signal, its maximum being limited by the breakdown voltage of the Zener diode ZD2.

[0039] Then at point (2) in Fig. 5 the voltage of the reflection signals, while at the same time the positive electric current of the reflection signals at point (12) in Fig. 6 via route (B) in Fig. 3 flows. The decay at point (2) is thus compensated to a certain extent at point (12). In combination with the fact that the reflection signals are biased outside the amplitude direction of the communication signals, this ensures that the reflection signals do not fall below the binarization voltage threshold Vt and prevents the reflection signals from exceeding the binarization voltage threshold Vt, unlike point (21) in Fig. Figure 7 illustrates a conventional example. In this way, it can be prevented that the reflection signals contaminate the communication signals. 0037 The positive electrical current of the reflection signals flows at point (13) in Fig. 6 during a low-side approach period over the path (B) in Fig. 4, generating a voltage equal to the negative supply voltage 8 minus the forward voltage of diode D2. At point (14), the reflection signals from the receiver side arrive after the reflection time t according to equation (2), and a negative electric current flows along path (A) into Fig. 4, so that the voltage of the positive communication signal 5 corresponds to the potential difference between the positive supply 7 and the negative supply 8 minus the breakdown voltage of the Zener diode ZD1.

[0040] Then at point (4) in Fig. 5 the voltage of the reflection signals, while at the same time the negative electric current of the reflection signals at point (14) in Fig. 6 across route (A) in Fig. 3 flows. The rise at point (4) is thus compensated to a certain extent at point (14). In combination with the fact that the reflection signals are biased outside the amplitude direction of the communication signals, this ensures that the reflection signals do not rise above the binarization voltage threshold Vt, and prevents the reflection signals from exceeding the binarization voltage threshold Vt, unlike point (23) in Fig. Figure 7 illustrates a conventional example. Accordingly, it can be prevented that the reflection signals contaminate the communication signals.

[0041] According to the present invention, the reflection signal attenuation circuit 10 of the push-pull transmitter circuit 2 comprises rectifier diodes D1 and D2 connected in series with the high-side driver element Q1 and the low-side driver element Q2, respectively, and Zener diodes ZD1 and ZD2 connected in parallel with the high-side driver element Q1 and the low-side driver element Q2, respectively, to add or subtract breakdown voltages approximately equal to 1.5 to 3 times the upper or lower limits for a HIGH level voltage (to provide limiting voltages). This biases the reflection signals outside the amplitude direction of the communication signals to prevent the amplitude of the communication signals from being affected by the reflection signals, thereby preventing the reflection signals from exceeding the binarization voltage threshold Vt and contaminating the communication signals.In this way, the attenuation of reflection signals can be easily achieved with a simple circuit configuration, without having to change the circuit when a different electrical conductor length is used.

[0042] It should be noted that although Zener diodes are used as the first and second voltage limiting elements in the preceding embodiment, examples of the first and second voltage limiting elements are not limited to them, but may also include TVS (or Transient Voltage Suppressors) and varistors.

[0043] While preferred features for carrying out the present invention have been discussed based on exemplary embodiments with reference to the drawings, the exemplary embodiments disclosed here should be considered illustrative and not limiting in every respect. The scope of the present invention is not defined by the above description, but by the claims. A person skilled in the art can readily imagine a multitude of changes and modifications that, in light of the present disclosure, fall within the realm of the obvious. Accordingly, it is assumed that such changes and modifications fall within the scope of application of the invention as defined by the claims or within its equivalent range. (Reference symbol) 1 Communication system 2 transmitter circuit 3 High-side driver signal 4 Low-side driver signal 5 positive communication signals 6 negative communication signal 7 positive supply 8 negative supply 10 Reflection signal attenuation circuit 20 Receiver circuit D1, D2 first and second rectifier elements (rectifier diodes) Q1, Q2 High-side driver element, Low-side driver element (driver transistors) Vt Binarization voltage threshold ZD1, ZD2 first and second voltage limiting element (Zener diodes) ZD3 Zener diode QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2024-177344

[0001] WO 2008 / 038388A1

[0015] JP 2009-296568A

[0015] JP 2011-239091A

[0016] JP 2016-051968A

[0016]

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