JP4978364B2 - Data transceiver - Google Patents

Description

  The present invention relates to a data transmission / reception apparatus capable of reducing the amount of data transmission / reception.

  As the functions and accuracy of systems increase, the number of analog sensors connected to electronic control devices (so-called ECUs) mounted on vehicles is constantly increasing.

  An electronic control device mounted on a vehicle has to take in the detection signal of such an analog sensor and execute a predetermined vehicle control based on the taken-in signal. A system for capturing a detection signal has been proposed.

For example, a system in which a detected analog signal is measured at a predetermined sampling period, converted into a digital signal by an A / D converter, and the converted digital data is transmitted to an electronic control device using high-speed communication means, or detection For example, Patent Document 1 discloses a system in which an analog signal is transmitted as it is on a data bus and is converted into a digital signal by an A / D converter in an electronic control device connected to the bus. reference).
Japanese Patent Laid-Open No. 11-27300

  However, conventionally, a system for transmitting an analog sensor detection signal to an electronic control device mounted on a vehicle has been proposed. However, in a system for transmitting an analog sensor detection signal after converting it to digital data, When the number of analog sensors increases, there is a problem that the data transmission amount increases and exceeds the design tolerance. In a system that transmits the analog sensor detection signal as an analog signal, it is vulnerable to noise, up to the analog sensor There is a problem that there is a restriction on the distance of the connector, and when the number of analog sensors is increased, the number of connector input terminals of the electronic control device is increased and the connector is enlarged.

  In order to solve the above-mentioned problem that the amount of data transmission increases and exceeds the design tolerance in a system in which the detection signal of the analog sensor is converted into digital data and transmitted, a method of reducing the sampling period is also available. However, the conversion accuracy of the detection signal of the analog sensor is lowered, and the controllability of the electronic control device may be seriously damaged.

  The present invention has been made in view of the above, and an object of the present invention is to provide a data transmitting / receiving apparatus capable of reducing the amount of data transmitted / received while maintaining practical accuracy as an analog sensor.

  To achieve the above object, the first invention comprises an analog signal input unit for inputting an analog signal, A / D conversion means for sampling the analog signal at a predetermined sampling period, and converting the analog signal into time-series digital data, Data transmission means for transmitting time-series digital data of a portion where the change is not constant among the time-series digital data converted by the A / D conversion means.

According to a second aspect of the present invention, in the data transmitting apparatus according to the first aspect, the data transmitting means includes the time-series digital data dn at the _nth sampling time point and the (n-1) th sampling time point before one sampling period. A difference data calculation unit that sequentially calculates _n- th difference data Δ _{n / n−1} (= d _n −d _n−1 ), which is a difference from the time-series digital data d _n−1 at n, The absolute value of the difference between the difference data Δ _{n / n−1} and the (n−1) th difference data Δ _{n−1 / n-2} one sampling period earlier calculated in the same manner is within a predetermined range. and whether the determined data determination unit or the data judging unit "is within a predetermined range" in based on the determination result, and the time-series digital data d _n in the n-th sampling time, the n th differential data Δ _{n /} Characterized in that it comprises a data transmission unit does not transmit a _-1.

The third invention is a data receiving apparatus for receiving data transmitted from the data transmitting apparatus according to the first or second aspect of the invention, digital data d _n of the n-th sampling time by the data transmission section Based on the detection result of the transmission detecting means for detecting whether or not the data has been transmitted, and “data not transmitted” by the transmission detecting means, the digital signal at the (n−1) th sampling time point before one sampling period data d _n-1, with the difference data received last, characterized in that it comprises a data interpolating means for interpolating the digital data d _n in the n-th sampling point was not sent.

  According to the data transmission / reception apparatus of the present invention, the amount of data transmission / reception can be reduced while maintaining the practical accuracy as an analog sensor.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

<Example 1>
FIG. 1 is a diagram showing a schematic configuration example of a data transmitting / receiving apparatus 400 according to the first embodiment of the present invention.

  A data transmitting / receiving apparatus 400 shown in FIG. 1 includes a data transmitting apparatus 100, a data receiving apparatus 200, and a data transmission path 300. Reference numeral 500 denotes a sensor that outputs an analog signal to the data transmitting / receiving apparatus 400.

  The data transmission apparatus 100 includes an analog signal input unit 110, an A / D conversion unit 120, and a data transmission unit 130. The A / D conversion unit 120 includes a sampling unit 121 and a quantization unit 122, and the data transmission unit 130 includes a difference data calculation unit 131, a data determination unit 132, and a data transmission unit 133. .

  The data receiving apparatus 200 includes a transmission detection unit 210 and a data interpolation unit 220.

  The operation of the data transmitting / receiving apparatus 400 shown in FIG. 1 will be described.

  The analog signal output from the sensor 500 is input to the sampling unit 121 in the A / D conversion unit 120 via the analog signal input unit 110 in the data transmission device 100.

The analog signal input to the sampling unit 121 in the A / D conversion unit 120 is sampled at a predetermined sampling period T, and then quantized (converted to digital data) by the quantization unit 122. Note that sampling and quantization are sequentially performed when an analog signal is input. FIG. 2 is a diagram illustrating a state in which an analog signal input to the A / D conversion unit 120 is sampled by the sampling unit 121 and quantized by the quantization unit 122. In FIG. 2, A is an analog signal inputted to the A / D conversion unit 120, T is the sampling _period, T 1 through T _n digital data sampling moment the sampling is _performed, d 1 to d _n is the quantized Indicates. In the present embodiment, n is an integer of 1 or more.

  FIG. 4 is a diagram for explaining processing executed by the data transmitting / receiving apparatus 400 using an example of data. Here, the operation of the data transmitting / receiving apparatus 400 will be described with reference to FIGS.

When the analog signal input unit 110 in the data transmission apparatus 100 is an analog signal A is input, the sampling unit 121 in the A / D converter 120 at the sampling time _{T 1,} samples the analog signal A. Sampled data is sent to the quantization unit 122, it is converted into digital data d _1. Next, the sampling unit 121 samples the analog signal A at a sampling time T ₂ when the sampling period T has elapsed from the sampling time T ₁ . Sampled data is sent to the quantization unit 122, it is converted into digital data d _2. Further, the sampling unit 121 at the sampling time T ₃ has elapsed from the sampling point T ₂ only sampling period T, samples the analog signal A. Sampled data is sent to the quantization unit 122, it is converted into digital data d _3. Such an operation is repeated, and the analog signal A input to the A / D conversion means 120 is sequentially sampled at a predetermined sampling period T, and then sequentially quantized (converted into digital data) by the quantization unit 122. The

The digital data d ₁ , d ₂ , d ₃ ... Quantized by the quantization unit 122 are sequentially input to the data transmission unit 130.

  Here, as an example, the analog signal A input to the analog signal input unit 110 in the data transmission device 100 is sampled by the sampling unit 121 in the A / D conversion means 120 and quantized (digitally) by the quantization unit 122. It is assumed that the data is converted into data and converted into digital data as shown in (c) in FIG.

The difference data calculation unit 131 in the data transmission means 130, with respect to the digital data of FIG. 4 (c) that is sequentially input, the digital data dn at the _nth sampling time and the (n-1) th sampling before one sampling period. The _n- th difference data Δ _{n / n−1} that is the difference from the digital data d _n−1 at the time is sequentially calculated. For _{example, Δ 2/1 = d 2 -d 1} , Δ 3/2 = d 3 -d 2, Δ 4/3 = d 4 -d 3, ···, Δ n-2 / n-3 = d n _{-2 -d n-3, Δ n} -1 / n-2 = d n-1 -d n-2, a _{Δ n / n-1 = d} n -d n-1. However, in the sampling time T _1, since there is no previous digital data, calculating difference data is not performed. The result of the calculated difference data Δ _{n / n−1} is shown in (d) of FIG.

The difference data (d) in FIG. 4 is sequentially input to the data determination unit 132 in the data transmission unit 130. The data determination unit 132 in the data transmission unit 130 includes the nth difference data Δ _{n / n−1} and the n−1th difference one sampling period before the sequentially input difference data in FIG. The absolute value | Δ _Δn | of the difference from the data Δ _{n−1 / n−2} is sequentially calculated. For example, | Δ _Δ3 | = Δ _3/2 −Δ _2/1 , | Δ _Δ4 | = Δ _4/3 −Δ _3/2 , | Δ _Δ5 | = Δ _5/4 −Δ _4/3 ,... , | Δ _Δn-2 | = Δ _{n−2 / n−3} −Δ _{n−3 / n−4} , | Δ _Δn−1 | = Δ _{n−1 / n−2} −Δ _{n−2 / n−3} , | _ΔΔn | = _{Δn / n−1} − _{Δn −1 / n−2} . However, in the sampling time T ₁ and the sampling time T _2, since there is no previous differential data, calculation of the absolute value of the difference is not performed. The result of the absolute value | Δ _Δn | of the calculated difference is shown in (e) of FIG. The fact that the absolute value | Δ _Δn | of the difference shown in (e) of FIG. 4 is small means that the input analog signal A and A / D converted digital data change at a nearly constant rate. It shows that. Further, the large value of the absolute value | Δ _Δn | of the difference indicates that the change in the analog signal A and the digital data after A / D conversion is not constant.

The data determination unit 132 in the data transmission means 130 uses a threshold value Δ _th for determining whether or not the absolute value | Δ _Δn | of the difference shown in (e) of FIG. 4 is within a predetermined range. Set. In FIG. 4, Δ _th = 2 is set as an example. Therefore, the data determination unit 132 in the data transmission unit 130 determines whether or not the absolute value | Δ _Δn | of the difference shown in (e) of FIG. 4 is 2 or less (however, the sampling time T in the case of ₁ and the sampling time T ₂ are, the determination is not performed). The shaded portion in FIG. 4 is a portion where the absolute value of the difference | Δ _Δn | ≦ 2. In this part, the input analog signal A and A / D converted digital data change at a rate that is almost constant.

Next, the data transmission unit 133 in the data transmission unit 130 transmits data based on the determination result of the data determination unit 132. When the data determination unit 132 determines that the absolute value | Δ _Δn |> 2 of the difference, the data transmission unit 133 determines the digital data dn at the _nth sampling time and the nth sampling time. transmitting the n-th differential data delta _{n / n-1} is the difference between the digital data d _n digital data d _n-1 at the sampling time of one sampling period before. For example, in the case of the sampling time T ₃ in FIG. 4, since the absolute value of the difference | Δ _Δ3 | = 3 (> 2), the digital data d ₃ and the difference data Δ _3/2 are transmitted and the sampling is performed. In the case of the time point T _n-5 , since the absolute value of the difference | Δ _Δn-5 | = 5 (> 2), the digital data d _n-5 and the difference data Δ _{n-5 / n-6} are transmitted. To do. However, if the sampling time T ₁ and the sampling time T ₂ are, since the determination has not been performed, always regardless of the value of data following the data is transmitted. That is, when the sampling time _{T 1,} only the digital data _{d 1} is transmitted, in the case of sampling time _{T 2,} the digital data _{d 2} and the difference data delta _2/1 is transmitted (FIG. 4 (f) refer) . A portion where the data transmission unit 133 transmits data is a portion without shading in FIG. 4 and a portion at the sampling time indicated by a solid line in FIG. FIG. 3 shows that the change of the analog signal A is not constant in this portion.

When the data determination unit 132 determines that the absolute value | Δ _Δn | ≦ 2 of the difference, the data transmission unit 133 does not transmit data, and instead, a flag “ Non "is transmitted. For example, at the sampling time T ₄ in FIG. 4, since | Δ _Δ4 | = 1 (≦ 2), data is not transmitted and “Non” is transmitted, and at the sampling time T _n−2 . Since | _ΔΔn−2 | = 2 (≦ 2), data is not transmitted and “Non” is transmitted. A portion where the data transmission unit 133 does not transmit data is a portion indicated by shading in FIG. 4 and a portion at the sampling time indicated by a dotted line in FIG. From FIG. 3, it can be seen that in this portion, the analog signal A changes at a rate almost constant.

  For a portion where the analog signal A is changing at a substantially constant rate, even if the digital data corresponding to the analog signal A at the sampling time of the portion is not transmitted, the digital data already received on the data receiving device side is received. Using the data and the difference data, digital data corresponding to the analog signal A at the sampling time of that portion can be calculated and interpolated. This will be described in the description of the data receiving apparatus below.

  Data transmitted from the data transmission device 100 is input to the data reception device 200 through the data transmission path 300. Transmission detection means 210 in data receiving apparatus 200 detects whether or not digital data at the n-th sampling time point has been transmitted. The detection is performed based on whether or not a flag “Non” indicating that data transmission is not performed is received from the data transmission unit 133 in the data transmission device 100.

Data receiving apparatus 200, transmits the detection means 210 in the data reception apparatus 200, when it is detected that the data has been transmitted, the corresponding digital data d _n received to the analog signal A at the n-th sampling time It is recognized as digital data. For example, in the case of the sampling time T ₃ in FIG. 4, since the digital data d ₃ has been received, d ₃ = 50 is recognized as the digital data corresponding to the analog signal A at the sampling time T ₃ .

When the transmission detecting unit 210 in the data receiving apparatus 200 detects that data has not been transmitted because the flag “Non” is received, the data interpolating unit 220 in the data receiving apparatus 200 has already from the digital data d _n-1 one cycle before the differential data delta _{n-1 / n-2} in one sampling period before the (n-1) th sampling time of the received digital data in the n-th sampling time d _n ′ is calculated as d _n ′ = d _n−1 + Δ _{n−1 / n−2,} and the calculated digital data d _n ′ is digital data (interpolated data) corresponding to the analog signal A at the n-th sampling time point. ) To interpolate. Further, when the state in which no data is transmitted (Non is received) continues, the data interpolation unit 220 interpolates the interpolated data d _n−1 ′ at the sampling time before one sampling period and the difference data Δ received last. from _{x / x-1,} 'the, _{d n'} digital data _{d n} in the n-th sampling time _{= d n-1 '+ Δ} x / x-1 and calculated, the calculated digital data _{d n} has' the current Interpolation is performed as digital data corresponding to the analog signal A at the time of sampling. In addition, x is an integer greater than or equal to 2 smaller than n-1.

For example, in the case of the sampling time T ₄ in FIG. 4, since the data is not received (Non was received), digital data d _{3 =} 50 that has already received the differential data delta _{3/2 =} - 1, the digital data d ₄ ′ at the sampling time T ₄ is calculated as d ₄ ′ = d ₃ + Δ _3/2 = 50 + (− 1) = 49, and the calculated digital data d ₄ ′ = 49 is calculated as the sampling time T ₄ is interpolated as digital data corresponding to the analog signal A. Further, since the data even sampling instant T ₅ is not received (Non was received), one sampling period calculating a preceding sampling time point data d ₄ '= 49 and the last differential data received in the delta _{3/2 =} - 1, the digital data d ₅ ′ at the sampling time T ₅ is calculated as d ₅ ′ = d ₄ ′ + Δ _3/2 = 49 + (− 1) = 48, and the calculated digital data d ₅ ′ = 48 is an analog signal. Interpolation is performed as digital data corresponding to A (see FIG. 4G).

  As described above, the data receiving apparatus 200 has already received the digital signal corresponding to the analog signal A at the sampling time of the portion of the portion where the analog signal A is changing at a substantially constant rate even if the digital data is not received. Using the received digital data and difference data, digital data corresponding to the analog signal A at the sampling time of that portion can be calculated and interpolated.

  FIG. 3 is a diagram showing that all the sampled and quantized digital data is transmitted by the conventional data transmission method. In FIG. 3, the digital data (all digital data) at the sampling point indicated by the solid line is transmitted. On the other hand, in FIG. 2 showing the operation of the data transmitting / receiving apparatus 400 of the present invention, the digital data at the sampling point indicated by the solid line, that is, the digital data corresponding to the analog signal at the portion where the change in the analog signal is not constant Although transmitted, the digital data at the sampling time indicated by the dotted line, that is, the digital data corresponding to the analog signal at the portion where the rate of change of the analog signal is almost constant is not transmitted. Thus, the data transmission / reception apparatus 400 of the present invention can reduce the data transmission amount. In the data transmission / reception apparatus 400 of the present invention, difference data is transmitted together with quantized digital data. However, the difference data itself has a small value and a small data amount, and therefore does not increase the data transmission amount. .

Further, as setting a threshold delta _th to a small value, the accuracy of digital data is calculated (interpolated) in the data receiving apparatus 200 is improved, the effect of reducing the data transmission amount is reduced. On the other hand, as to set a threshold delta _th to a large value, the accuracy of digital data is calculated (interpolated) in the data receiving apparatus 200 is reduced, the effect to reduce the data transmission amount is increased. Or to give priority to accuracy, by either preferentially the effect of reducing the data transmission amount may be set threshold delta _th to an appropriate value.

As described above, according to the data transmitting / receiving apparatus of the first embodiment, the differential data is transmitted together with the sampled and quantized digital data, and further, the portion where the analog signal is changing at a substantially constant rate is detected, By not transmitting that portion of data, the amount of data transmitted and received can be reduced, and the burden on the data transmitting and receiving apparatus during data transmission and reception can be reduced. Further, reduction of data transmission amount, since not intended to be achieved by lowering the sampling period, not the dropping greatly conversion accuracy of the analog signal, by setting the threshold delta _th to an appropriate value, practical The data transmission / reception amount can be reduced while maintaining the conversion accuracy.

  The data transmission / reception device 400 is mounted on a vehicle, for example. The data transmission device 100 is, for example, a CPU incorporating an A / D converter, and the data reception device 200 is, for example, an electronic control device ( Part of a so-called ECU). The data transmitting apparatus 100 may be composed of a CPU as data transmitting means and an external A / D converter. The sensor is, for example, a temperature sensor, and when the temperature is relatively stable and the temperature change is small, the frequency of data transmission can be greatly reduced, and the data transmission / reception amount can be reduced.

<Example 2>
FIG. 5 is a diagram showing a schematic configuration example of the data transmitting / receiving apparatus 401 according to the second embodiment of the present invention. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. The difference from FIG. 1 is the configuration of the data transmission apparatus 101. The sensors (1) 500-1 to (N) 500-N are a plurality of sensors that output analog signals to the data transmission / reception device 401.

  The data transmission apparatus 101 includes an analog signal input unit 110-1 to an analog signal input unit 110-N, A / D conversion unit (1) 120-1 to A / D conversion unit (N) 120-N, and data transmission unit 140. It is composed of The configuration of the A / D conversion means (1) 120-1 to A / D conversion means (N) 120-N is the same as that of the A / D conversion means 120 in the data transmitting / receiving apparatus 400 shown in FIG. The data transmission unit 140 includes a difference data calculation unit 141, a data determination unit 142, and a data transmission unit 143. The data transmission unit 140 is configured to connect a plurality of A / D conversion units.

  The data transmission unit 143 in the data transmission unit 140 is input from the A / D conversion unit (1) 120-1 to the A / D conversion unit (1) 120-N based on a request from the data reception device 200. Data to be transmitted is selected from the data, and the data is transmitted to the data receiving apparatus 200 via the data transmission path 300. For example, when there is a data request for the sensor (1) 500-1 from the data receiving apparatus 200, the data sampled and quantized by the A / D conversion means (1) 120-1 is transmitted via the data transmission path 300. To the data receiving device 200. The method of processing sampled and quantized data and performing transmission / reception is exactly the same as the content described in the first embodiment, and has the same transmission / reception data reduction effect as in the first embodiment.

As described above, even in the configuration of the data transmitting / receiving apparatus 401 according to the second embodiment, the difference data is transmitted together with the sampled and quantized digital data, and further, the portion where the analog signal is changing at a substantially constant rate is detected. However, by not transmitting that portion of data, the amount of data transmission can be reduced, and the load on the data transmission / reception apparatus during data transmission can be reduced. Further, reduction of data transmission amount, since not intended to be achieved by lowering the sampling period, not the dropping greatly conversion accuracy of the analog signal, by setting the threshold delta _th to an appropriate value, practical The data transmission / reception amount can be reduced while maintaining the conversion accuracy.

  The data transmission / reception device 401 is mounted on, for example, a vehicle, the data transmission device 101 is a CPU including a plurality of A / D converters, and the data reception device 200 is, for example, an electronic control. It is a part of an apparatus (so-called ECU). The data transmitting apparatus 101 may be composed of a CPU as data transmitting means and a plurality of external A / D converters. The sensor is, for example, a temperature sensor, and when the temperature is relatively stable and the temperature change is small, the frequency of data transmission can be greatly reduced, and the data transmission / reception amount can be reduced.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the first embodiment, in order to facilitate understanding, there is a part where specific numerical values are shown to explain the operation of the data transmission device of the present invention. The present invention can be applied without being limited to the numerical values shown.

  In the first and second embodiments, there is a portion describing an example in which the transmission / reception device of the present invention is mounted on a vehicle, but the present invention is applied without being limited to the case where the transmission / reception device is mounted on a vehicle. be able to.

It is a figure which shows the example of a schematic structure of the data transmitter / receiver 400 of Example 1 of this invention. It is a figure which shows a mode that the analog signal input into the A / D conversion means 120 is sampled by the sampling part 121, and is quantized by the quantization part 122. It is a figure which shows that all the data sampled and quantized by the conventional data transmission method are transmitted. It is a figure for demonstrating the process performed with the data transmitter / receiver 400 using the example of data. It is a figure which shows the example of a schematic structure of the data transmitter / receiver 401 of Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Data transmission apparatus 101 Data transmission apparatus 110 Analog signal input part 110-1 Analog signal input part 110-N Analog signal input part 120 A / D conversion means 120-1 A / D conversion means (1)
120-N A / D conversion means (N)
REFERENCE SIGNS LIST 121 sampling unit 122 quantization unit 130 data transmission unit 131 differential data calculation unit 132 data determination unit 133 data transmission unit 140 data transmission unit 141 differential data calculation unit 142 data determination unit 143 data transmission unit 200 data reception device 210 transmission detection unit 220 Data Interpolating Means 300 Data Transmission Line 400 Data Transmitting / Receiving Device 401 Data Transmitting / Receiving Device 500 Sensor 500-1 Sensor (1)
500-N sensor (N)
d ₁ to d _n digital data T ₁ through T _n sampling instants T sampling period A analog signals

Claims (3)

An analog signal input section for inputting an analog signal;
A / D conversion means for sampling the analog signal at a predetermined sampling period and converting it into time-series digital data;
A data transmission device comprising: data transmission means for transmitting time-series digital data of a portion where the change is not constant among the time-series digital data converted by the A / D conversion means. The data transmission means includes
n th n-th differential data delta _n is the difference between the time series digital data d _n-1 in the (n-1) th sampling time point of the time series digital data d _n and one sampling period preceding the sampling time A difference data calculation unit that sequentially calculates _{/ n−1} (= d _n −d _n−1 ),
The absolute value of the difference between the n-th difference data Δ _{n / n−1} and the n−1-th difference data Δ _{n−1 / n-2} one sampling period before calculated in the same manner is a predetermined range. A data determination unit for determining whether or not the
The data determination unit based on the "is within a predetermined range" and the judgment result, the time series digital data d _n in the n-th sampling instant, and the n-th differential data delta _{n / n-1} The data transmission apparatus according to claim 1, further comprising a data transmission unit that does not transmit the data. A data receiving device for receiving data transmitted from the data transmitting device according to claim 1 or 2,
A transmission detecting means for digital data d _n in the n-th sampling time by the data transmission unit detects whether not transmitted,
Based on the detection result of the "data is not sent" on the transmission detector, 1 and digital data d _n-1 in the (n-1) th sampling time prior sampling period, the last received differential data DOO using the data receiving device, characterized in that it comprises a data interpolating means for interpolating the digital data d _n in the n-th sampling point was not sent.

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