JP2019193045A - Device and method for error rate estimation - Google Patents

Abstract

To estimate an error rate with high accuracy.SOLUTION: A waveform measurement unit 101 measures a waveform of voltage between a communication line 501 and a power line 503. From the measuring voltage waveform which is a voltage waveform measured by the waveform measurement unit 101, a noise measurement unit 103 measures a noise width, which is the width of an induction noise induced from a power line 502 to the communication line 501, and a noise period which is a period in which the induction noise has been induced. Based on the noise width and the noise period measured by the noise measurement unit 103, an error rate estimation unit 104 estimates an error rate. A display unit 107 displays information indicative of the error rate estimated in the error rate estimation unit 104.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an error rate estimation device and an error rate estimation method.

  Currently, a technology is known in which a plurality of equipment is connected to each other by a three-core cable including a communication line, a first power supply line, and a second power supply line, and communication and power supply are realized with a simple configuration. ing. In this technique, a plurality of facility devices are supplied with AC power from an AC power supply via a first power supply line and a second power supply line. The plurality of equipment devices communicate with each other by baseband transmission using the communication line and the second power supply line.

  For example, Patent Literature 1 describes an air conditioner including an outdoor unit and an indoor unit that are connected to each other by such a three-core cable. In the technique described in Patent Document 1, since the distance between the communication line, the first power supply line, and the second power supply line is very short, induced noise is induced from the first power supply line to the communication line. There is. When such inductive noise occurs, the signal waveform is distorted and the error rate in baseband transmission increases. Here, for example, there is a desire to know the error rate in order to determine whether stable baseband transmission is feasible.

JP 11-193950 A

  However, Patent Document 1 does not describe any technique for estimating the error rate. For example, in the method of estimating the error rate from the type and length of the three-core cable, there is a high possibility that the estimation accuracy cannot be increased. For this reason, a technique for accurately estimating the error rate is desired.

  The present invention has been made in view of the above problems, and an object thereof is to provide an error rate estimation device and an error rate estimation method for accurately estimating an error rate.

In order to achieve the above object, an error rate estimation apparatus according to the present invention provides:
A plurality of facilities connected to each other by a communication line, a first power line, and a second power line and receiving AC power from an AC power source via the first power line and the second power line An error rate estimation device for estimating an error rate in baseband transmission using the communication line and the second power line by a device,
Waveform measuring means for measuring a waveform of a voltage between the communication line and the second power supply line;
From the measured voltage waveform which is the waveform of the voltage measured by the waveform measuring means, a noise width which is a width of induced noise induced from the first power supply line to the communication line, and the induced noise are induced. A noise measuring means for measuring a noise period which is a period;
Error rate estimating means for estimating the error rate based on the noise width and the noise period measured by the noise measuring means;
Display means for displaying information indicating the error rate estimated by the error rate estimation means.

  In the present invention, from the waveform of the voltage between the communication line and the second power supply line, the noise width, which is the width of the induced noise induced from the first power supply line to the communication line, and the period in which the induced noise is induced. Are measured, and the error rate is estimated based on the noise width and the noise period. Therefore, according to the present invention, the error rate can be estimated with high accuracy.

The figure which shows the structure of the communication system with which the error rate estimation apparatus which concerns on Embodiment 1 of this invention is applied. Diagram showing the configuration related to the communication function in equipment The figure which shows the physical structure of the error rate estimation apparatus which concerns on Embodiment 1 of this invention. Diagram showing measured voltage waveform Diagram showing applied voltage waveform Diagram showing differential waveform Diagram showing partial waveform The flowchart which shows the error rate estimation process which the error rate estimation apparatus which concerns on Embodiment 1 of this invention performs Figure showing the display screen Explanatory drawing of the bit determination process which the error rate estimation apparatus which concerns on Embodiment 2 of this invention performs

  Embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
First, a communication system 1000 to which the error rate estimation apparatus 100 according to Embodiment 1 of the present invention is applied will be described with reference to FIG. The communication system 1000 is a communication system for which an error rate is to be estimated. The communication system 1000 includes a facility device 200, a facility device 300, and a cable 500, and the facility device 200 and the facility device 300 communicate with each other by baseband transmission via the cable 500. In the present embodiment, the communication system 1000 is an air conditioning system that executes air conditioning of a space to be air conditioned while the outdoor unit and the indoor unit communicate with each other.

  The facility device 200 is a device that communicates with the facility device 300 via the cable 500. In the present embodiment, it is assumed that the facility device 200 is an outdoor unit. The facility device 300 is a device that communicates with the facility device 200 via the cable 500. In the present embodiment, it is assumed that the facility device 300 is an indoor unit. The cable 500 is a three-core cable having a communication line 501, a power line 502, and a power line 503 as core lines. The communication line 501 is an electric wire to which a signal voltage in baseband transmission is applied. The power supply line 502 is an electric wire set at the power supply potential in the AC power supply 400. The power supply line 502 corresponds to the first power supply line. The power line 503 is an electric wire set to the ground potential in the AC power source 400. The power supply line 503 corresponds to the second power supply line.

  The facility device 200 and the facility device 300 are connected to each other by a communication line 501, a power line 502, and a power line 503. The facility device 200 and the facility device 300 are supplied with AC power from the AC power source 400 via the power line 502 and the power line 503. The facility device 200 and the facility device 300 communicate with each other by baseband transmission using the communication line 501 and the power supply line 503.

  The AC power source 400 supplies AC power to the facility device 200 and the facility device 300 via the power line 502 and the power line 503. The effective value of the AC voltage in this AC power is, for example, 100V or 200V. Moreover, the frequency of this alternating current power is 50 Hz or 60 Hz, for example. The AC power source 400 is a commercial power source provided by an electric power company, for example.

  Here, with reference to FIG. 2, the structure regarding the communication function in the equipment 200 is demonstrated easily. The configuration related to the communication function in the facility device 300 is basically the same as the configuration related to the communication function in the facility device 200, and thus the description thereof is omitted. As illustrated in FIG. 2, the facility device 200 includes an AC load 201, a DC power source 202, and a communication module 203 as a configuration related to a communication function.

  The AC load 201 is a load that uses AC power supplied via the power line 502 and the power line 503 as a power source. The AC load 201 is, for example, a compressor that compresses a refrigerant or a blower that blows air. The DC power supply 202 is a power supply that converts AC power supplied via the power supply line 502 and the power supply line 503 into DC power, and generates Vcc, which is a DC power supply voltage. Vcc is, for example, 24V, 12V, or 5V. The DC power source 202 includes, for example, a rectifier circuit, a smoothing circuit, and a transformer circuit.

  The communication module 203 communicates with the communication module of the communication partner using the DC power supply voltage generated by the DC power supply 202. The communication module 203 includes a transmission circuit 204 and a reception circuit 205. The transmission circuit 204 is a circuit that transmits a frame to be transmitted by switching a voltage applied between the communication line 501 and the power supply line 503 in accordance with a bit pattern constituting the frame to be transmitted. The reception circuit 205 is a circuit that specifies a bit pattern constituting a reception target frame by measuring a voltage between the communication line 501 and the power supply line 503 and receives the reception target frame.

  In the present embodiment, it is assumed that an NRZ method using NRZ (Non Return to Zero) as a transmission line code in baseband transmission is adopted. In the NRZ system, the voltage between the communication line 501 and the power supply line 503 is V1 (V) or 0 (V) during a period representing a code for 1 bit (hereinafter referred to as “1 bit period” as appropriate). Maintained. In this embodiment, since the power supply line 503 is set to the ground potential, the communication line 501 is set to the potential of V1 (V) or the ground potential. In the present embodiment, the communication speed is assumed to be 625 bps (bit per second).

  Next, the error rate estimation apparatus 100 will be described. First, the physical configuration of the error rate estimation apparatus 100 will be described with reference to FIG. The error rate estimation apparatus 100 physically includes a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a flash memory 14, an RTC (Real Time Clock) 15, and a touch screen. 16, an A / D (Analog / Digital) converter 17, and a communication interface 18. The components included in the error rate estimation apparatus 100 are connected to each other via a bus.

  The CPU 11 controls the overall operation of the error rate estimation apparatus 100. The CPU 11 operates according to a program stored in the ROM 12 and uses the RAM 13 as a work area. The ROM 12 stores a program and data for controlling the overall operation of the error rate estimation apparatus 100. The RAM 13 functions as a work area for the CPU 11. That is, the CPU 11 temporarily writes programs and data in the RAM 13 and refers to these programs and data as appropriate.

  The flash memory 14 is a nonvolatile memory that stores various types of information. The RTC 15 is a time measuring device. The RTC 15 includes, for example, a battery, and keeps timing while the power of the error rate estimation apparatus 100 is off. The RTC 15 includes an oscillation circuit including a crystal oscillator, for example.

  The touch screen 16 detects a touch operation performed by the user and supplies a signal indicating the detection result to the CPU 11. The touch screen 16 displays an image based on the image signal supplied from the CPU 11 or the like. As described above, the touch screen 16 functions as a user interface of the error rate estimation apparatus 100.

  The A / D converter 17 converts an analog signal into a digital signal. The communication interface 18 is an interface for connecting the error rate estimation apparatus 100 to a communication network. The error rate estimation device 100 can communicate with various devices connected to the communication network via the communication network. The communication interface 18 includes a LAN (Local Area Network) interface such as a NIC (Network Interface Card).

  Next, the function of the error rate estimation apparatus 100 will be described with reference to FIG. The error rate estimation apparatus 100 includes an error rate in baseband transmission using the communication line 501 and the power line 503 by the equipment 200 and the equipment 300 connected to each other by the communication line 501, the power line 502, and the power line 503. Is estimated. The error rate estimation apparatus 100 estimates the bit error rate based on the waveform of the voltage between the communication line 501 and the power supply line 503, and further estimates the frame error rate based on the bit error rate. The bit error rate is the probability that a 1-bit code is transmitted in error. The frame error rate is a probability that at least one code among a plurality of bits included in one frame is erroneously transmitted. Hereinafter, when the bit error rate and the frame error rate are collectively referred to as appropriate, they are simply referred to as an error rate.

  In the communication system 1000, the communication line 501, the power supply line 502, and the power supply line 503 are combined into one cable 500, and the power supply line 503 is used together with the communication line 501 among the power supply line 502 and the power supply line 503 used for supplying AC power. Used for communication. For this reason, in the communication system 1000, the total number of electric wires used for power supply and communication is small, and power supply and communication can be realized with a simple configuration.

  However, in the communication system 1000, the communication lines 501, the power lines 502, and the power lines 503 are very close to each other. For this reason, for example, there is a high possibility that induced noise is induced from the power supply line 502 to the communication line 501 by an AC voltage applied between the power supply line 502 and the power supply line 503. Due to the influence of this induction noise, the potential of the communication line 501 fluctuates, and as a result, the error rate may increase. On the other hand, if the error rate is too high, it is desirable to take some measures. Therefore, the error rate estimation apparatus 100 displays information indicating the error rate as a material for estimating the error rate and determining whether or not some measure should be taken.

  As shown in FIG. 1, the error rate estimation apparatus 100 functionally includes a waveform measurement unit 101, a control unit 102 including a noise measurement unit 103 and an error rate estimation unit 104, a storage unit 105, and an operation reception. Unit 106, display unit 107, and communication unit 108. The waveform measuring unit 101 corresponds to, for example, a waveform measuring unit. The noise measuring unit 103 corresponds to, for example, a noise measuring unit. The error rate estimation unit 104 corresponds to, for example, error rate estimation means.

  The waveform measurement unit 101 measures the voltage waveform between the communication line 501 and the power supply line 503. The waveform measurement unit 101 measures the waveform of the voltage by, for example, sampling a voltage signal supplied from a probe connected to the communication line 501 and the power supply line 503 at a predetermined sampling period. This voltage waveform is hereinafter referred to as “measurement voltage waveform” as appropriate. Information indicating the measurement voltage waveform is supplied from the waveform measurement unit 101 to the control unit 102 and is stored in the storage unit 105 by the control unit 102. The function of the waveform measuring unit 101 is realized by the function of the A / D converter 17, for example.

  The control unit 102 controls the entire error rate estimation apparatus 100. In addition, the control unit 102 executes a process with a large amount of calculation in the error rate estimation process. The function of the control part 102 is implement | achieved, for example, when CPU11, ROM12, and RAM13 cooperate.

  The noise measurement unit 103 measures a noise width and a noise period from the measurement voltage waveform. This noise width is the width of the induced noise induced from the power supply line 502 to the communication line 501. This noise cycle is a cycle in which this induced noise is induced. In addition, when the AC power supply 400 connected to the power supply line 502 and the power supply line 503 is a commercial power supply, it is considered that inductive noise is generated at a cycle corresponding to the cycle of the commercial power supply. Typically, inductive noise is considered to occur at the positive peak and the negative peak in the AC voltage. In this case, the noise period is half the period of the AC power supply 400.

  However, depending on the environment in which the communication system 1000 is installed, the type of the communication module 203, the type of the cable 500, the length of the cable 500, etc., one of the positive peak and the negative peak in the AC voltage There is also a possibility that inductive noise is generated only at the peak, two or more inductive noises are generated for one peak, or inductive noise is generated at a cycle that is an integral multiple of the cycle of the AC power supply 400. It is done. Therefore, even when the error rate estimation apparatus 100 can specify the period of the AC power supply 400, it is desirable to measure the noise period according to the above condition.

  Further, the noise width is considered to depend on conditions such as the environment in which the communication system 1000 is installed, the type of the communication module 203, the type of the cable 500, and the length of the cable 500. Therefore, the error rate estimation apparatus 100 measures the noise width according to the above conditions. On the other hand, if the above conditions do not change, there is a high possibility that the noise period and noise width will not change. For this reason, the error rate estimated based on the measured noise period and the measured noise width is considered to be effective if the above conditions do not change.

  In addition, when there exists dispersion | variation in a noise period, the average value of the measured several noise period is employable, for example. Further, when the noise width varies, for example, an average value of a plurality of measured noise widths can be employed. The function of the noise measuring unit 103 is realized by, for example, the cooperation of the CPU 11, the ROM 12, and the RAM 13.

  The error rate estimation unit 104 estimates the error rate based on the noise width and noise period estimated by the noise measurement unit 103. Basically, the shorter the noise period, the higher the error rate, and the wider the noise width, the higher the error rate. Basically, the noise width is the width of a portion of the entire induced noise having an amplitude that affects the bit determination. The function of the error rate estimation unit 104 is realized by the cooperation of the CPU 11, the ROM 12, and the RAM 13, for example.

  The storage unit 105 stores various types of information related to error rate estimation processing. For example, the storage unit 105 includes information indicating a bit determination method employed in the communication system 1000, information indicating a bit pattern and transmission timing of a frame transmitted and received by the communication system 1000, information indicating a communication speed, and an error rate. Is stored. The function of the storage unit 105 is realized by the function of the flash memory 14, for example.

  The operation reception unit 106 receives various operations related to the error rate estimation process from the user. For example, the operation reception unit 106 specifies an operation for instructing the start of the error rate estimation process, an operation for designating a bit determination method adopted in the communication system 1000, a bit pattern and a transmission timing of a frame transmitted and received by the communication system 1000. An operation to specify, an operation to specify a communication speed, and an operation to instruct display of information indicating an error rate are received from the user. The function of the operation reception part 106 is implement | achieved by the function of the touch screen 16, for example.

  The display unit 107 displays various information related to the error rate estimation process. For example, the display unit 107 displays information indicating the error rate estimated by the error rate estimation unit 104. The display unit 107 displays a screen for accepting various operations by the operation accepting unit 106. The function of the display unit 107 is realized by, for example, the cooperation of the CPU 11 and the touch screen 16.

  The communication unit 108 transmits and receives various types of information related to error rate estimation processing to and from various types of devices connected to the communication network. For example, the communication unit 108 transmits the information indicating the bit determination method, the information indicating the bit pattern and transmission timing of the transmitted / received frame, and the information indicating the communication speed to the facility device 200, the facility device 300, or the facility device 200. And the control device that controls the facility equipment 300. For example, the communication unit 108 transmits information indicating an error rate to a display device connected to the communication network. The function of the communication unit 108 is realized by, for example, the cooperation of the CPU 11 and the communication interface 18.

Here, the error rate estimation unit 104 estimates the bit error rate in the baseband transmission based on the noise width, the noise period, and the bit determination method employed in the baseband transmission. Further, the error rate estimation unit 104 estimates the frame error rate based on the bit error rate and the frame length. The frame length is the number of bits included in one frame. For example, the error rate estimation unit 104 calculates a frame error rate based on the following equation (1). Note that FER represents a frame error rate, BER represents a bit error rate, and N represents a frame length.
FER = 1- (1-BER) ^ N (1)

  The display unit 107 displays information indicating at least one of the bit error rate and the frame error rate. That is, the display unit 107 may display information indicating only the bit error rate, display information indicating only the frame error rate, or information indicating both the bit error rate and the frame error rate. May be displayed. The display unit 107 may display information indicating the frame error rate for each frame length.

  Here, the transmission-side facility device among the facility device 200 and the facility device 300 communicates either one of the first voltage and the second voltage that is lower than the first voltage. The voltage is applied between the line 501 and the power supply line 503. The first voltage is, for example, 5V. The second voltage is, for example, 0V. Of the equipment 200 and equipment 300, the equipment on the receiving side makes a bit determination from the comparison result between the voltage between the communication line 501 and the power line 503 and the threshold voltage. The threshold voltage is an intermediate voltage between the first voltage and the second voltage. The threshold voltage is, for example, 2.5V. For example, when the voltage between the communication line 501 and the power supply line 503 exceeds the threshold voltage, the receiving-side equipment determines that the bit is “1”, and between the communication line 501 and the power supply line 503. If the voltage does not exceed the threshold voltage, it is determined that the bit is “0”.

  The noise measurement unit 103 sets a period having an amplitude exceeding the margin voltage in the difference waveform as a noise period. The noise measuring unit 103 measures the length of the noise period as the noise width, and measures the period of the noise period as the noise period. The difference waveform is a difference waveform between the measurement voltage waveform and the applied voltage waveform. The applied voltage waveform is a waveform of a voltage applied between the communication line 501 and the power supply line 503 by the transmission side equipment. The margin voltage is a difference voltage between the first voltage and the threshold voltage, and is also a difference voltage between the second voltage and the threshold voltage. For example, when the first voltage is 5V, the second voltage is 0V, and the threshold voltage is 2.5V, the margin voltage is 2.5V.

  The measurement voltage waveform, the applied voltage waveform, and the difference waveform will be described with reference to FIGS. 4, 5, and 6. First, as shown in FIG. 5, the applied voltage waveform is a waveform having a first voltage or a second voltage for each bit period in accordance with the bit pattern to be transmitted. Tbit represents one bit period. Vth represents a threshold voltage. V1 represents the first voltage of 5V. 0V represents the second voltage. In FIG. 5, the applied voltage waveform is applied in accordance with a 7-bit bit pattern of “0”, “1”, “0”, “1”, “1”, “0”, “1”. The situation is shown. In FIG. 5, a downward arrow indicates a position (hereinafter referred to as “determination position” as appropriate) for determining the bit level in the receiving-side equipment. In the present embodiment, as shown in FIG. 5, an example in which the bit level is determined only once per bit will be described. Note that the determination position is assumed to be the center in one bit period. For example, the receiving-side equipment can specify the determination position from the detection position of the start bit that is the first bit of the frame.

  In addition, if the error rate estimation apparatus 100 can identify the bit pattern of the frame transmitted by the transmission-side facility device, it can identify the applied voltage waveform. For example, when information indicating the bit pattern is stored in the storage unit 105, the error rate estimation apparatus 100 can specify the applied voltage waveform based on the information indicating the bit pattern. Alternatively, the error rate estimation apparatus 100 may estimate the applied voltage waveform from the measured voltage waveform. That is, the waveform of the induced noise is basically a mountain shape in the positive direction or the negative direction, and is not a rectangular waveform like the applied voltage waveform, but is estimated to have a shape that can be estimated to some extent. Because.

  Further, the error rate estimation apparatus 100 may detect an idle state and acquire a measured voltage waveform in the idle state. In this case, the applied voltage waveform is a voltage waveform in which a voltage of 0 V is continued. The idle state is a state in which neither the equipment device 200 nor the equipment device 300 transmits a frame, and a voltage is applied between the communication line 501 and the power supply line 503 by the equipment device 200 and the equipment device 300. There is no state.

  As shown in FIG. 4, the measured voltage waveform is a waveform obtained by adding a noise waveform that is a voltage waveform of induced noise to the applied voltage waveform. In the present embodiment, obtaining one voltage waveform by adding the voltages included in each voltage waveform by aligning the time axes of the two voltage waveforms is referred to as adding two voltage waveforms. Also, obtaining one voltage waveform by subtracting the voltage contained in each voltage waveform with the time axes of the two voltage waveforms aligned is referred to as taking the difference between the two voltage waveforms.

  FIG. 4 shows an example in which positive induced noise is induced in a 1-bit period expressed as Bit3 and negative induced noise is induced in a 1-bit period expressed as Bit6. Here, in the 1-bit period expressed as Bit3, the voltage applied between the communication line 501 and the power supply line 503 by the transmission side equipment is 0V. Further, the amplitude of the positive induction noise at the determination position in the 1-bit period expressed as Bit3 is V2 which is larger than the margin voltage Vm. In this case, the voltage on the measurement voltage waveform at the determination position in the 1-bit period expressed as Bit3 is V2 that is larger than the threshold voltage Vth. Therefore, the receiving-side facility device erroneously determines that the code is “1” in the bit determination in the 1-bit period expressed as Bit3.

  On the other hand, in the 1-bit period expressed as Bit6, the voltage applied between the communication line 501 and the power supply line 503 by the transmission side equipment is 0V. The amplitude of the negative induced noise at the determination position in the 1-bit period expressed as Bit6 is V3 that is larger than the margin voltage Vm. In this case, the voltage on the measurement voltage waveform at the determination position in the 1-bit period expressed as Bit6 is −V3, which is smaller than −Vth. However, since -V3 is not a voltage smaller than Vth, the receiving-side equipment correctly determines that the sign is “0” in the bit determination in the 1-bit period expressed as Bit6. .

  As described above, when the amplitude of the induced noise at the determination position is larger than the margin voltage, whether or not an erroneous determination is made depends on the relationship between the sign value and the sign of the induced noise. Specifically, when the sign is ‘1’ and the induced noise is positive, and when the sign is ‘0’ and the induced noise is negative, no erroneous determination is made. On the other hand, when the sign is ‘1’ and the induced noise is negative, and when the sign is ‘0’ and the induced noise is positive, an erroneous determination is made. In the present embodiment, the probability that a positive induced noise occurs is the same as the probability that a negative induced noise occurs, and the probability that the sign is “1” and the probability that the sign is “0” are the same. If the amplitude of the induced noise at the determination position is larger than the margin voltage, it is determined that the determination is erroneous with a probability of 50%. On the other hand, when the amplitude of the induced noise at the determination position is smaller than the margin voltage, no erroneous determination is made.

  As shown in FIG. 6, the difference waveform is a difference waveform between the measurement voltage waveform and the applied voltage waveform, and is a voltage waveform of induced noise. In the differential waveform, Pn1 and Pn2 which are periods having an amplitude exceeding the margin voltage Vm are noise periods. Pn1 is a period from t1 to t2. Pn2 is a period from t3 to t4. And the length of Pn1 and Pn2 is calculated | required as a noise width. When the length of Pn1 and the length of Pn2 are different, the average value of the length of Pn1 and the length of Pn2 is obtained as the noise width. Also, Tn, which is the length from the center of Pn1 to the center of Pn2, is obtained as the noise period. When three or more noise periods are detected, the average value of the lengths between the centers of adjacent noise periods can be adopted as the noise period.

  Here, as described above, the receiving-side equipment compares the voltage between the communication line 501 and the power supply line 503 and the threshold voltage once for one bit, and determines the bit from the result of one comparison. judge. When the error rate estimation unit 104 determines whether the determination position overlaps the noise period while shifting the determination position by a predetermined shift amount from the beginning of the partial waveform to the end of the partial waveform, A rate that is half of the rate at which the determination position and the noise period are determined to overlap is estimated as the bit error rate. The partial waveform is a waveform corresponding to the noise period in the differential waveform.

  FIG. 7 shows a partial waveform. Here, the waveform of the period from t1 to t3 among the differential waveforms is adopted as the partial waveform. However, the partial waveform may be a waveform corresponding to the noise period extracted from the differential waveform. For example, the partial waveform may be a waveform in a period from t2 to t4 in the differential waveform. As shown in FIG. 7, the partial waveform includes one noise period. If the determination position overlaps with the noise period, an erroneous determination is made with a probability of 50%. On the other hand, when the determination position does not overlap with the noise period, no erroneous determination is made.

  Note that the difference waveform is expected to be a repetition of a partial waveform. Accordingly, it is possible to estimate the bit error rate by determining whether or not the determination position and the noise period overlap while shifting the determination position in one partial waveform. For example, when the shift amount is 1/1000 of the noise period, it is determined whether or not the determination position and the noise period overlap at 1000 determination positions, and 1000 determination results are obtained. Here, for example, it is assumed that it is determined that the determination position and the noise period overlap only 4 times out of 1000 determinations. In this case, it is estimated that an erroneous determination is made at 50% of the four determination positions, that is, at the two determination positions. Therefore, in this case, the bit error rate is estimated to be 0.002.

  Next, an error rate estimation process executed by the error rate estimation apparatus 100 will be described with reference to the flowchart shown in FIG. The error rate estimation process is started when the error rate estimation apparatus 100 is turned on.

  First, the error rate estimation apparatus 100 acquires communication related information (step S101). For example, the error rate estimation apparatus 100 acquires communication related information from the user via the operation reception unit 106. Alternatively, the error rate estimation device 100 acquires communication related information from various devices connected to the communication network via the communication unit 108. The communication related information is, for example, information indicating a bit pattern and transmission timing of a frame transmitted by the facility device 200 or the facility device 300, information indicating a communication speed, or information indicating a bit determination method. The bit determination method is, for example, the number of determination positions provided for one bit. If there are a plurality of determination positions, the sign of the bit is determined by, for example, majority determination.

  When the error rate estimation apparatus 100 completes the process of step S101, the error rate estimation apparatus 100 measures the voltage waveform (step S102). For example, the error rate estimation apparatus 100 controls the waveform measurement unit 101 to measure a voltage waveform. When the error rate estimation apparatus 100 completes the process of step S102, the error rate estimation apparatus 100 determines whether or not the period during which the voltage waveform is measured is in an idle state (step S103). The error rate estimation apparatus 100 can determine whether or not the idle state is based on the measured voltage waveform.

  When it is determined that the error rate estimation apparatus 100 is in the idle state (step S103: YES), the applied voltage waveform in the idle state is specified (step S104). This applied voltage waveform is a voltage waveform in which a voltage of 0 V continues. If it is determined that the error rate estimation apparatus 100 is not in the idle state (step S103: NO), the bit rate is specified (step S105). The applied voltage waveform is basically a combination of rectangular waves, and the voltage waveform of induced noise is basically not rectangular. Therefore, the error rate estimation apparatus 100 can separate the applied voltage waveform and the voltage waveform of induced noise from the measured voltage waveform. Note that the voltage waveform of the induced noise is a differential waveform.

  When the error rate estimation apparatus 100 completes the process of step S105, the error rate estimation apparatus 100 specifies the applied voltage waveform from the bit pattern (step S106). When the error rate estimation apparatus 100 completes the process of step S104 or the process of step S106, the error rate estimation apparatus 100 specifies a differential waveform (step S107).

  When the error rate estimation apparatus 100 completes the process of step S107, the error rate estimation apparatus 100 specifies a noise period (step S108). When the error rate estimation apparatus 100 completes the process of step S108, the error rate estimation apparatus 100 specifies the noise width (step S109). When the error rate estimation apparatus 100 completes the process of step S109, the error rate estimation apparatus 100 specifies a noise period (step S110).

  When the error rate estimating apparatus 100 completes the process of step S110, the error rate estimating apparatus 100 estimates the bit error rate (step S111). For example, the error rate estimation apparatus 100 estimates the bit error rate based on the partial waveform extracted from the differential waveform, the noise width, and the noise period. When the error rate estimation apparatus 100 completes the process of step S111, the error rate estimation apparatus 100 estimates the frame error rate using the above-described equation (1) (step S112). When the error rate estimation apparatus 100 completes the process of step S112, the error rate estimation apparatus 100 displays the error rate (step S113).

  FIG. 9 shows a display screen 800 that is a screen for displaying information indicating an error rate. The display screen 800 is a screen that presents information indicating a bit error rate and a frame error rate. The display screen 800 may be a screen that presents information indicating a frame error rate for each frame length. When the error rate estimation apparatus 100 completes the process of step S113, the error rate estimation process is completed.

  As described above, in the present embodiment, the noise width that is the width of the induced noise induced from the power line 502 to the communication line 501 from the waveform of the voltage between the communication line 501 and the power line 503, and the induced noise A noise period, which is a period in which is induced, is measured, and an error rate is estimated based on the noise width and the noise period. Therefore, according to the present embodiment, the error rate can be estimated with high accuracy.

(Embodiment 2)
In the first embodiment, the example in which the comparison for bit determination is performed once for one bit has been described. In the present invention, comparison for bit determination may be performed a plurality of times for one bit. In the present embodiment, an example in which comparison for bit determination is performed three times for one bit will be described. If the number of determinations in the error rate estimation apparatus 100 is the same as the number of determinations in the equipment device 200 and the equipment device 300, an improvement in accuracy of error rate estimation can be expected.

  In this embodiment, the receiving-side equipment compares the voltage between the communication line 501 and the power supply line 503 and the threshold voltage multiple times for one bit, and makes a majority decision using the multiple comparison results. The bit is determined by

  Here, the error rate estimation unit 104 shifts the plurality of determination positions by a predetermined shift amount from the beginning of the partial waveform to the end of the partial waveform, and the majority of the determination positions among the plurality of determination positions. When it is determined whether or not it overlaps with the noise period, a half of the ratio at which the majority of determination positions are determined to overlap with the noise period is estimated as the bit error rate.

  FIG. 10 shows an example in which three determination positions of a determination position indicated by t11, a determination position indicated by t12, and a determination position indicated by t13 are set as determination positions for one bit. In FIG. 10, the partial waveform is simplified, and it is schematically shown that the period from t1 to t2 is a noise period, and the period from t2 to t3 is a non-noise period.

  The determination position indicated by t11 and the determination position indicated by t12 overlap with the noise period, and the determination position indicated by t13 does not overlap with the noise period. Therefore, in the determination position group shown in FIG. 10, it is determined that a majority of the determination positions overlap with the noise period. Thereafter, the determination position group is shifted by a predetermined shift amount, and the majority decision is similarly made. For example, when the shift amount is 1/1000 of the noise period, the majority decision is made 1000 times. Then, a rate that is half of the rate at which the majority of the determination positions are determined to overlap the noise period is estimated as the bit error rate.

  Note that the number and interval of determination positions in the error rate estimation apparatus 100 are preferably the same as the interval and interval of determination positions in the equipment device 200 and the equipment device 300. As described above, it is expected that the bit error rate estimation accuracy is improved by matching the bit determination conditions in the error rate estimation apparatus 100, the facility device 200, and the facility device 300.

(Modification)
As mentioned above, although embodiment of this invention was described, when implementing this invention, a deformation | transformation and application with a various form are possible. In the present invention, which part of the configuration, function, and operation described in the above embodiment is adopted is arbitrary. Further, in the present invention, in addition to the configuration, function, and operation described above, further configuration, function, and operation may be employed.

  For example, in the first embodiment, an example in which the communication line 501, the power line 502, and the power line 503 are included in one three-core cable 500 has been described. The present invention is also applicable when the communication line 501, the power line 502, and the power line 503 are included in separate cables. Even in such a configuration, if the distances between the communication line 501, the power line 502, and the power line 503 are short, induced noise may be induced from the power line 502 to the communication line 501.

  In the first embodiment, an example in which the communication system 1000 is an air conditioning system, the equipment device 200 is an outdoor unit, and the equipment device 300 is an indoor unit has been described. Of course, in the present invention, the communication system 1000 is not limited to an air conditioning system. For example, the communication system 1000 may be a lighting system, the equipment device 200 may be a lighting control device, and the equipment device 300 may be a lighting device.

  By applying an operation program that defines the operation of the error rate estimation apparatus 100 according to the present invention to an existing personal computer or information terminal device, the personal computer or the like may function as the error rate estimation apparatus 100 according to the present invention. Is possible. Further, such a program distribution method is arbitrary. For example, the program is stored and distributed in a computer-readable recording medium such as a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disk), or a memory card. Alternatively, it may be distributed via a communication network such as the Internet.

  Various embodiments and modifications can be made to the present invention without departing from the broad spirit and scope of the present invention. Further, the above-described embodiment is for explaining the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is shown not by the embodiments but by the claims. Various modifications within the scope of the claims and within the scope of the equivalent invention are considered to be within the scope of the present invention.

  The present invention is applicable to a communication system in which a plurality of facility devices are connected to each other by a communication line and a pair of power supply lines.

11 CPU, 12 ROM, 13 RAM, 14 Flash memory, 15 RTC, 16 Touch screen, 17 A / D converter, 18 Communication interface, 100 Error rate estimation device, 101 Waveform measurement unit, 102 Control unit, 103 Noise measurement unit 104 error rate estimation unit, 105 storage unit, 106 operation reception unit, 107 display unit, 108 communication unit, 200, 300 equipment, 201 AC load, 202 DC power supply, 203 communication module, 204 transmission circuit, 205 reception circuit, 400 AC power supply, 500 cable, 501 communication line, 502,503 power supply line, 800 display screen, 1000 communication system

Claims (7)

A plurality of facilities connected to each other by a communication line, a first power line, and a second power line and receiving AC power from an AC power source via the first power line and the second power line An error rate estimation device for estimating an error rate in baseband transmission using the communication line and the second power line by a device,
Waveform measuring means for measuring a waveform of a voltage between the communication line and the second power supply line;
From the measured voltage waveform which is the waveform of the voltage measured by the waveform measuring means, a noise width which is a width of induced noise induced from the first power supply line to the communication line, and the induced noise are induced. A noise measuring means for measuring a noise period which is a period;
Error rate estimating means for estimating the error rate based on the noise width and the noise period measured by the noise measuring means;
Display means for displaying information indicating the error rate estimated by the error rate estimation means,
Error rate estimation device. The error rate estimation means estimates a bit error rate in the baseband transmission based on the noise width and the noise period,
The display means displays information indicating an error rate of at least one of the bit error rate estimated by the error rate estimation means and a frame error rate estimated from the bit error rate;
The error rate estimation apparatus according to claim 1. The error rate estimation means estimates the frame error rate based on the bit error rate and a frame length that is the number of bits included in one frame.
The error rate estimation apparatus according to claim 2. Of the plurality of facility devices, the transmission-side facility device uses either the first voltage or the second voltage that is lower than the first voltage as the communication line and the first voltage. Between the two power lines,
Among the plurality of facility devices, the facility device on the receiving side is a threshold value that is a voltage between the communication line and the second power supply line and an intermediate voltage between the first voltage and the second voltage. The bit is judged from the comparison result with the voltage,
The noise measuring means is a difference waveform between the measured voltage waveform and an applied voltage waveform that is a waveform of a voltage applied between the communication line and the second power line by the transmission-side equipment. In the difference waveform, a period having an amplitude exceeding a margin voltage, which is a difference voltage between the first voltage and the threshold voltage, is measured as a noise period, and the length of the noise period is measured as the noise width, Measuring the period of the noise period as the noise period;
The error rate estimation apparatus according to claim 2 or 3. The receiving-side facility device compares the voltage between the communication line and the second power supply line and the threshold voltage once for one bit, and determines the bit from the result of one comparison,
The error rate estimation means shifts the determination position by a predetermined shift amount from the beginning of a partial waveform that is a waveform corresponding to the noise period of the difference waveform to the end of the partial waveform, and performs the determination. When it is determined whether or not the position overlaps with the noise period, a ratio of half of the ratio determined that the determination position and the noise period overlap is estimated as the bit error rate.
The error rate estimation apparatus according to claim 4. The receiving-side equipment compares the voltage between the communication line and the second power supply line and the threshold voltage a plurality of times for one bit, and makes a majority decision using a plurality of comparison results. The bit is judged by
The error rate estimation means shifts a plurality of determination positions by a predetermined shift amount from the beginning of a partial waveform that is a waveform corresponding to the noise period of the difference waveform to the end of the partial waveform, When determining whether or not a majority of the determination positions of the plurality of determination positions overlap with the noise period, a ratio of half of the ratio determined that the majority of determination positions overlap with the noise period is the bit. Estimate as error rate,
The error rate estimation apparatus according to claim 4. A plurality of facilities connected to each other by a communication line, a first power line, and a second power line and receiving AC power from an AC power source via the first power line and the second power line An error rate estimation method for estimating an error rate in baseband transmission using the communication line and the second power line by a device,
Measuring a voltage waveform between the communication line and the second power line;
A noise width that is a width of induced noise induced from the first power supply line to the communication line from a measured voltage waveform that is a waveform of the measured voltage, and a noise period that is a period in which the induced noise is induced And measure
Estimating the error rate based on the measured noise width and the noise period;
Error rate estimation method.

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