JP2763380B2 - Signal characteristics measurement equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a signal system characteristic measuring device for measuring a signal distortion characteristic value of a signal system, and to enable accurate and automatic measurement of a dynamically changing signal distortion characteristic value. For the purpose, by storing time-series data of signal data transmitted from the signal system to be measured, a storage unit for storing inspection data for inspection included in the signal data, and a storage unit for storing the inspection data Data conversion means for calculating and outputting an output signal corresponding to the input signal in accordance with a data conversion function of a data conversion structure to which an internal state value is assigned using the signal data as an input signal; When the storage means holds the test data, a value at which a signal distortion characteristic value which gives a data state of the test data is output from the data conversion means is set. The configuration is as follows.

[Industrial applications]

The present invention relates to a signal system characteristic measuring apparatus for measuring a signal distortion characteristic value of a signal system which outputs an output signal by applying signal distortion to an input signal such as a wireless or wired transmission line or a modem. More particularly, the present invention relates to a signal system characteristic measuring device that enables accurate and automatic measurement of a dynamically changing signal distortion characteristic value.

With the development of the information society in recent years, wireless and wired communication networks have been developed in Japan and overseas, and information exchange using communication technology has become an important foundation of society. With this, in addition to conventional TV broadcasts, radio broadcasts, telephone calls, etc., highly socially influential items such as inter-company transaction information and bank online information are transmitted using the communication network. It is becoming. With the growing demand for communication of such important information, more than ever,
The need to establish accurate transmission technology to reduce errors received due to the characteristics of the transmission path has been pressing,
In response to this, development of an equalizer that performs high-precision equalization processing has been called out.

In order to realize an equalizer that performs this high-precision equalization processing, the development of an adaptive equalizer that adaptively performs the equalization processing according to the distortion characteristics of the transmission path has to be developed. In addition to being indispensable, in order to realize the adaptive processing, it is necessary to provide a transmission line characteristic measuring device capable of accurately measuring the distortion characteristic of the transmission line. Such a characteristic measuring apparatus can accurately measure the characteristic of a transmission line that dynamically changes, as can be understood by assuming application to digital mobile communication, for example. It is necessary to make a simple configuration.

[Conventional technology]

Conventionally, inspection data transmitted from the transmission side and a received signal of the inspection data received via the transmission path are observed with a synchroscope or the like, and the distortion characteristics of the transmission path are empirically measured from the comparison result. I was taking the method of going. At this time, assuming a mathematical model of the distortion characteristic of the transmission line, and interpreting the obtained comparison result according to the assumed mathematical model, the distortion characteristic of the transmission line is measured. In some cases, a method was adopted. In any case, in the related art, an operator intervenes so as to measure the distortion characteristic of the transmission line by a manual operation.

In addition, even when detecting the distortion characteristic of an electronic device such as a modulation / demodulation device without being limited to the distortion characteristic of the transmission line, the processing is performed to measure the distortion characteristic by a similar manual operation. .

[Problems to be solved by the invention]

However, such a conventional technique has a problem that distortion characteristics of a signal system cannot be automatically and continuously measured. That is, for example, when the transmission path used constantly changes, such as digital mobile communication,
In practice, there is a problem that the distortion characteristics cannot be measured.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a new signal system characteristic measuring device that enables accurate and automatic measurement of a signal distortion characteristic value of a dynamically changing signal system.

[Means for solving the problem]

 FIG. 1 is a diagram illustrating the principle of the present invention.

In the figure, 10 is a signal system characteristic measuring device equipped with the present invention, 20
Is a signal system to be measured, 30 is a learning processing device, and 40 is a learning signal storage device.

The signal system characteristic measuring device 10 includes a storage unit 11, a data conversion unit 12, and an internal state value storage unit 13.

The storage unit 11 performs processing to hold time-series data of signal data transmitted from the signal system 20.

The data conversion unit 12 calculates the signal data held in the storage unit 11 as an input signal, and calculates an output signal corresponding to the input signal according to a data conversion function of a data conversion structure such as a network structure to which an internal state value is allocated. Then, the signal distortion characteristic value of the signal system 20 is measured and output. Since the data conversion means 12 measures and outputs the signal distortion characteristic value of the signal system 20, the data conversion means 12 adopts a configuration of outputting an output signal corresponding to the type of the signal distortion characteristic value. However, in the case of realizing with a single data conversion structure, output signals corresponding to all types of signal distortion characteristic values are output from the data conversion structure. Data conversion structure for the number of types (types and structures may be different)
In this case, an output signal corresponding to the kind of signal distortion characteristic value assigned from each data conversion structure is output.

The internal state value storage means 13 performs processing to store the internal state value allocated to the data conversion structure of the data conversion means 12. This internal state value adjusts the data conversion function of the data conversion means 12 by, for example, modulating a signal value which is allocated to an internal connection between the processing units constituting the data conversion structure and output to the internal connection destination. Will be.

The learning processing device 30 controls the internal of the data conversion means 12 according to a predetermined algorithm so that the output signal group from the data conversion means 12 output in response to the presentation of the learning input signal group becomes a desired teacher signal group. The state value is learned, and the learned value is registered in the internal state value storage means 13. Here, the learning processing device 30 does not necessarily perform the learning by using the data conversion unit 12 of the signal system characteristic measuring device 10.
It is not necessary to use a simulator. For example, a simulator of the data conversion unit 12 constructed on a computer may be used.

The learning signal storage device 40 stores the specific test data output from the signal system 20 as a group of learning input signals used by the learning processing device 30, and stores the signal distortion characteristic value of the signal system 20 that provides the test data. The processing is performed so as to be stored as a teacher signal group for learning used by the learning processing device 30. It is preferable that the data state of the signal located before the test data used at this time is specified to a specific value such as “0” in order to stabilize the data state of the test data.

[Action]

In the present invention, first, it is assumed that the operator inputs predetermined input test data to the signal system 20 to be measured, and various signal distortion characteristic values (for example, , Amplitude distortion, delay distortion, phase distortion, etc.), and collects output information (inspection data) of input inspection data from the signal system 20 output by being distorted by the assumed signal distortion characteristic value. . This collection process is executed, for example, by constructing a mathematical model of the signal system 20 and using the constructed mathematical model by computer simulation. Then, the operator sends the collected inspection data information to the learning processing device.
A learning signal storage device 40 as an input signal for learning used by 30
In addition, the corresponding signal distortion characteristic value assumed at that time is registered in the learning signal storage device 40 as a learning teacher signal used by the learning processing device 30.

When the learning signal is stored in the learning signal storage device 40,
The operator activates the learning processing device 30. When activated, the learning processing device 30 starts the registered learning signal storage device 40
The learning value of the internal state value of the data conversion means 12 is obtained by using the learning signal of (1), and the learned value is stored in the internal state value storage means 13. The internal state value obtained by this learning process is
When a signal of test data is input from the signal system 20, the data conversion means 12 has a characteristic of operating so as to output a signal distortion characteristic value resulting from the test data.

When the processing of setting the internal state value in the internal state value storage means 13 is completed, the operator subsequently operates the signal system characteristic measuring device.
Start 10 When started, the storage unit 11 of the signal system characteristic measuring device 10 operates to hold time-series data of signal data transmitted from the signal system 20. The input inspection data used to collect the learning signal
With the configuration in which the test data is input to 20, it is possible to adopt a configuration in which the test data used for learning is periodically included in the signal data transmitted in this manner. From this, the storage unit 11 operates to periodically hold the test data used for learning, for example, and in response to this holding operation, the data conversion unit 12 sets the signal distortion characteristic value of the signal system 20 to have. Will be output in real time.

As described above, by providing the signal system characteristic measuring apparatus 10 of the present invention, the signal distortion characteristic value of the dynamically changing signal system 20 can be accurately and automatically measured.

〔Example〕

Hereinafter, the present invention will be described in detail according to an embodiment to which a process of measuring characteristics of a transmission path is applied.

FIG. 2 shows an embodiment of the present invention. In the figure, the first
The same components as those described in the figure are indicated by the same signals.

Reference numeral 50 denotes a demodulator, which performs demodulation processing of signal data transmitted from the transmission path. This demodulator 50
Is used to perform demodulation processing, a band-pass filter 51 for band-limiting the signal data transmitted from the transmission path with its carrier frequency, and when the output signal of the band-pass filter 51 is larger than a zero value, A limiter 52 that amplifies to a + HI level and amplifies to a −HI level when smaller than a zero value. An I-channel signal and a Q-channel signal quadrature-modulated by delay detection of an output signal of the limiter 52. A low-pass filter 54 for removing harmonic components of the I-channel signal demodulated by the delay detector 53, and an A / D converter 55 for converting an output signal of the low-pass filter 54 into a digital signal. A low-pass filter 56 for removing harmonic components of the Q-channel signal demodulated by the delay detector 53, and a digital signal And an A / D converter 57 for converting the signal into a signal.

11a is a tapped delay line, which is an A / D on the I channel side.
12a is a hierarchical network configuration data conversion means that receives data held in the tapped delay line 11a as input, and executes data conversion processing according to the hierarchical network structure. By doing so, processing is performed to measure the characteristic value of the distortion of the transmission path. Here, in this embodiment, since the characteristic value of the distortion of the transmission line to be measured is assumed to be one type, the output of the hierarchical network configuration data conversion means 12a is shown in one output format.

FIG. 3 shows this hierarchical network configuration data conversion means.
The basic configuration of the basic unit 1 that constitutes 12a is illustrated. As shown in this figure, a basic unit 1 is a multi-input one-output system, and a multiplication processing unit 2 for multiplying a plurality of inputs by an internal state value of each internal connection, and a total multiplication result thereof. It is configured to include an accumulation processing unit 3 for adding, and a function processing unit 4 that performs processing such as non-linear threshold processing on the accumulated value and outputs one final output.

Then, the hierarchical network configuration data conversion means 12a
As shown in FIG. 4, a basic unit 1 having such a configuration and an input unit 1 'for distributing an input signal value held by a tapped delay line 11a are constituted as a unit. An input layer constituted by units 1'-h, an intermediate layer constituted by one or a plurality of basic units 1-i and provided in one or more stages (one stage in this embodiment), It has an output layer (one unit in this embodiment) composed of a plurality of basic units 1-j, and has an input unit 1'-h and a basic unit 1-j.
i, between the basic units 1-i of the intermediate layer,
The basic unit 1-i and the basic unit 1-j are configured to have a hierarchical network structure formed by mutually interconnecting the basic units.

In this embodiment, the input layer is composed of seven input units 1'-h and the intermediate layer is composed of fifteen basic units 1-i having a one-stage configuration for the sake of convenience in the following description. It is assumed that the output layer is constituted by one basic unit 1-j, assuming that the characteristic value of the road distortion is one type. Here, since it is assumed that the characteristic value of the distortion of the transmission path to be measured is one type, the number of the basic units 1-j in the output layer is one unit. , The number of the basic units 1-j in the output layer is set to 2 units, or the number of the basic units 1-j in the output layer is 1
Hierarchical network configuration data conversion means 12 as a unit
Such a configuration that two a are provided is adopted. When a plurality of hierarchical network configuration data converters 12a are provided, one tap delay line 11a may be commonly used, or may be provided corresponding to each. Further, the hierarchical network structure of each hierarchical network configuration data conversion means 12a does not necessarily have to be the same.

The hierarchical network configuration data conversion means 12a configured as described above responds to an input signal input according to a data conversion function defined by a hierarchical network structure and an internal state value assigned to an internal connection of the hierarchical network structure. The function of converting to an output signal is exhibited. This hierarchical network configuration data conversion means
12a can be constituted by either program means or hardware means. However, when constituted by hardware means, the present invention is applied to the method disclosed in Japanese Patent Application No. 63-21, filed by the present applicant.
No. 6865 (filed on Aug. 31, 1988, "Network Configuration Data Processing Apparatus").

As described with reference to FIG. 1, in order to construct the signal system characteristic measuring apparatus 10 as an apparatus capable of measuring the distortion characteristic of a transmission path to be measured, first, the hierarchical network configuration data conversion means 12a is used to measure the distortion characteristics of the transmission path. It is necessary to obtain a learning signal for learning the internal state value of. The acquisition of the learning signal is realized by, for example, a mathematical model of a transmission path.

In the case of digital mobile communication, for example, the transmission path can be modeled by multipath. For example, as shown in FIG. 5, a direct wave from a transmitter modulator and an amplitude A transmission path can be modeled by a model in which a reflected wave subjected to distortion, delay distortion, and phase distortion is input to the demodulator 50. That is, the orthogonal-modulated waveform from the modulator, when it is _{I (t) cosω c t +} Q (t) sinω c t, the I channel, A (I (t-τ ) cosω c (t- φ) + Q (t−τ) sinω _c (t−φ)) where A: amplitude distortion τ: delay distortion (normalized to 0 ≦ τ ≦ 1) φ: phase distortion (normalized to 0 ≦ τ ≦ 1) The transmission path is modeled by a model in which reflected waves are added.

When a model of such a transmission path is established, the operator assumes that, for example, the modulator on the transmission side inputs an I-channel signal “010” to the transmission path to be measured.
For example, by using a computer simulation method, while simulating the signal of “010” that is distorted according to the transmission path model and simulating the processing of the demodulator 50, the distorted “ By collecting the demodulated signal of "010", "010"
The demodulated signals of “10” among the demodulated signals of “1” are collected. This collection process is executed by setting various values of A defining the magnitude of the amplitude distortion, values of τ defining the magnitude of the delay distortion, and values of φ defining the magnitude of the phase distortion. Will be.
Here, the demodulated signal of “10” of the demodulated signal of “010” is collected. If the demodulated signal of “10” is simply collected, the bit state of the signal located before that is collected. The reason for this is that the demodulated signal does not become stable.

FIG. 6 shows an example of the demodulated signal of “10” of “010” collected by the computer simulation method. Here, the demodulated signal assumes various magnitudes of delay distortion values τ in the model of the transmission path in FIG.
Is set to “1.0” and the phase distortion value φ is set to “0”, and it is assumed that demodulation is performed with the inverted format “101”. The lower right axis in the figure represents the sampling time, and the vertical axis represents the signal amplitude. This demodulated signal is to be input to the tapped delay line 11a of the signal system characteristic measuring device 10, and as shown in FIG.
The data for seven sampling times obtained by oversampling the output of 50 at four times the original period is input to the tapped delay line 11a. That is, the “10” demodulated signal sampled at 7 points is a tapped delay line.
11a.

The operator, with the demodulated signal collected in this way,
The distortion value used to generate the demodulated signal (the value of the delay distortion value τ in this embodiment because delay distortion is assumed as a measurement target) is determined by the internal state of the hierarchical network configuration data conversion means 12a. It is registered in the learning signal storage device 40 described with reference to FIG. 1 as a learning signal for learning a value. Then, the operator subsequently activates the learning processing device 30 described with reference to FIG.

When the demodulated signal of the learning signal stored in the learning signal storage device 40 is input to the tapped delay line 11a, the learning processing device 30
The hierarchical network configuration data converting means 12 outputs the delay distortion value of the learning signal associated with the demodulated signal from the output layer basic unit 1-j.
The learning of the internal state value of a is executed. In addition,
As described in the section of "Means for Solving the Problems", the learning processing device 30 uses the hierarchical network configuration data conversion means 12a which is always used as a measuring device when executing the learning. No need.

The learning processing device 30 executes this learning process by, for example, the back propagation method. That is, the learning processing device 30 has a three-layer hierarchical network structure of h layer-i layer-j layer shown in FIG. 4 according to the back propagation method, and the function processing unit 4 of the basic unit 1 has a sigmoid function. In this case, the output signal y from the output layer is output when an input signal for learning (demodulated signal) is presented.
_{When pj} and a learning teacher signal d _pj (delay distortion value) which is a signal to be taken by the output signal y _pj are determined, first, the difference value [d between the output signal Y _pj and the teacher signal d _pj [d _pj −y _pj )
And then calculate α _pj = y _dj (1−y _pj ) (d _pj −y _pj ), , The update amount ΔW _ji of the internal state value W _ji between the i-th layer and the j-th layer
(T) is calculated. Here, t is the number of times of learning, and then, using the calculated α _pj , , Then The update amount ΔW _ih of the internal state value W _ih between the h-th layer and the i-th layer
(T) is calculated. Then, the internal state value _{W ji (t) = W ji} (t-1) + ΔW ji (t) W ih (t) = W ih (t-1) for the next update cycle according to the update amount calculated as described above + [Delta] W By repeating the method of determining _ih (t), when the demodulated signal of the learning signal is input to the tapped delay line 11a,
The internal state value at which the delay distortion value of the learning signal associated with the demodulated signal is output from the basic unit 1-j of the output layer of the hierarchical network configuration data conversion means 12a.

The operator registers the learning value of the internal state value obtained by the learning processing device 30 in the internal state value storage means 13 to complete the construction processing of the signal system characteristic measuring device 10.

In order to measure the delay distortion value τ given by the transmission line, the transmitter-side modulator transmits the signal “010” of the I channel used when generating the demodulation signal for learning. Take a configuration. In the signal transmission processing, for example, when the modulator performs transmission signal transmission processing using a packet as shown in FIG. 7, the signal "010" is inserted into the training sequence of the packet. It can be realized by going. in this way,
When a signal for detecting the delay distortion value τ is inserted into the training sequence, means for generating a frame synchronization clock indicating the start of a packet from the demodulated I-channel signal is inserted into the training sequence. Means for generating a bit synchronization clock for detecting a signal position of “010”, and the clock signal generated by these means is used to demodulate the I-channel “010” signal of the I channel. It is necessary to detect when the “10” signal is held in the tapped delay line 11a.

"01" of the I channel demodulated by the tapped delay line 11a
When the "10" signal of the "0" signal is held, the seven input units 1'-h of the input layer of the hierarchical network configuration data conversion means 12a send the held data held by the tapped delay line 11a to the intermediate layer. Distribute to 15 basic units 1-i.
When receiving the signal value from the input unit 1'-h,
The basic unit 1-i of the intermediate layer first calculates a multiplication value of those input values and the corresponding internal state value stored in the internal state value storage means 13, and then calculates the sum of the calculated values. The output value is obtained by performing a calculation and subsequently performing a function conversion process assigned to the total value, and outputs the output value to one basic unit 1-j of the output layer. Upon receiving the signal values from this intermediate layer basic unit 1-i, the output layer basic unit 1-j likewise firstly receives those input values and the corresponding values stored in the internal state value storage means 13. An output value is obtained by calculating a multiplication value with the internal state value, then calculating a total value of the calculated value, and subsequently performing a function conversion process assigned to the total value. Output values. The output value from the hierarchical network configuration data conversion means 12a indicates the delay distortion value τ given on the transmission path to be measured, corresponding to the registered internal state value being registered.

In this way, every time the "10" signal of the I-channel "010" signal demodulated by the tapped delay line 11a is held, the hierarchical network configuration data conversion means 12a transmits the signal on the transmission path to be measured. The given delay distortion value τ is output.

Next, a result of a simulation performed to verify the effectiveness of the present invention will be described.

In this simulation, as the transmission distortion state based on the transmission line model shown in FIG. 5, seven values of the amplitude distortion value A are set in steps of “0.1” from “0.4” to “1.0”, and the delay distortion value τ By setting five points in the range of “0.4” to “0.8” in increments of “0.1”, a total of 35 types are assumed. Then, the demodulated signal of the above-mentioned “010” signal generated by computer simulation for generating the learning signal is divided into six types of bit states of the signal before and after the “010” signal for each assumed transmission distortion state. Assuming that a total of 210 points are generated, the generated 210-point “010” “10” demodulated signal is used as an input signal for learning, and the delay distortion value τ resulting in the demodulated signal is used for learning. , The corresponding internal state value is learned by the simulator of the hierarchical network configuration data conversion means 12a constructed on the computer.

Next, the learning value of the internal state value is set in the simulator of the hierarchical network configuration data conversion means 12a constructed on the computer, and the 210 points “1” generated as the learning signal are set.
By inputting the demodulated signal “0” to the simulator, it is determined whether or not a desired delay distortion value τ is output from the hierarchical network configuration data conversion means 12a. And then, "010" different from the one generated for learning
By assuming three types of bit states of the signal before and after the signal, a demodulated signal of 105 “010” signals different from the 210 points generated for learning is generated, and the generated 105 “ By inputting the demodulated signal “10” of “010” to the simulator, the hierarchical network configuration data conversion means 12
This was performed by determining whether or not a desired delay distortion value τ was output from a. Here, since it is assumed that the function processing unit 4 of the basic unit 1 of the hierarchical network configuration data conversion means 12a executes threshold processing using a sigmoid function, the output from the hierarchical network configuration data conversion means 12a is "0". The analog level is between "1" and "1".

FIG. 8 illustrates the results of this simulation. As shown in this figure, when the demodulated signal waveform used for learning is input, the correct answer rate of the delay distortion value τ output from the hierarchical network configuration data conversion means 12a is “95.24%” when the allowable error is 0.05, When the tolerance was 0.1, it was "100%". When an unknown demodulated signal waveform other than for learning is input, the correct answer rate of the delay distortion value τ output from the hierarchical network configuration data converter 12a is “97.14%” when the allowable error is 0.05%, But
When it was 0.1%, it was "100%". in this way,
From this simulation result, it is confirmed that the use of the present invention makes it possible to detect the distortion value of the transmission path with high accuracy.

Although the illustrated embodiment has been described above, the present invention is not limited to this. For example, in the embodiment, the delay unit 11a with a tap is disclosed as the storage unit 11 described with reference to FIG. 1. However, the storage unit 11 is not limited to this and may use a storage element such as a ring register or a FIFO element. Good. Also, the data conversion means 12 of FIG. 1 discloses a data conversion means 12a having a hierarchical network structure employing a hierarchical network structure. However, the present invention is not limited to this. It may have a data conversion structure.

In the embodiment, a signal waveform output from the quadrature modulation system has been described as an example, but a signal waveform output from another modulation system such as phase modulation or frequency modulation may be used.
Also, the disclosed transmission signal demodulator 50 is merely an example, and various other demodulator configurations can be employed. Further, in the embodiment, an example using the I channel has been described. However, it is also possible to use the Q channel or both the I channel and the Q channel.

Further, to be more specific, in the embodiments, the transmission path (including the demodulator) has been disclosed as the signal system to be measured. However, the present invention is not limited to this, and any signal system that generates signal distortion is not limited to this. Can be applied as is.

〔The invention's effect〕

As described above, according to the present invention, it is possible to realize a signal system characteristic measuring device capable of accurately and automatically measuring a signal distortion characteristic value of a dynamically changing signal system. This provides a way to enable real-time control of the equalizer according to the signal distortion characteristic value detected by the signal system characteristic measuring device of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the principle of the present invention, FIG. 2 is an embodiment of the present invention, FIG. 3 is a basic block diagram of a basic unit, FIG. FIG. 5 is an explanatory diagram of a transmission path model, FIG. 6 is an explanatory diagram of a demodulated signal used as a learning signal, FIG. 7 is an explanatory diagram of a transmission signal, and FIG. 8 is an explanatory diagram of a simulation result It is. In the figure, 10 is a signal system characteristic measuring device, 11 is storage means, 12 is data conversion means, 13 is internal state value storage means, 20 is a signal system,
Reference numeral 30 denotes a learning processing device, and reference numeral 40 denotes a learning signal storage device.

Continuing from the front page (72) Inventor Yasuyuki Oishi 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Co., Ltd. Document JP-A-52-128037 (JP, A) JP-A-51-7810 (JP, A) JP-A-51-108506 (JP, A) JP-A-1-184472 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G01D 21/00 G06F 15/18 G01R 31/00

Claims (4)

(57) [Claims] An apparatus for measuring a signal characteristic of a signal system to measure a signal distortion characteristic value of the signal system, wherein the apparatus stores time-series data of signal data transmitted from a signal system to be measured. Storage means (11) for holding test data for inspection included in the signal data; and data of a data conversion structure to which an internal state value is assigned by using the signal data held by the storage means (11) as an input signal. Data conversion means (12) for calculating and outputting an output signal corresponding to the input signal according to the conversion function, wherein the storage means (11) stores the test data as an internal state value of the data conversion means (12). When the data conversion means (12) is held, the data conversion means (12) is configured to set a value at which a signal distortion characteristic value that brings the data state of the inspection data is output. Signal characteristic measuring device. 2. The signal characteristic measuring device according to claim 1, wherein the data converting means (12) are prepared by the number of types of the signal distortion characteristic values, and each of the prepared data converting means (1) is provided.
The data conversion structure of 2) is configured to output one output signal, and as the internal state value of each data conversion means (12), a signal distortion characteristic value of a type assigned from each data conversion means (12) A signal system characteristic measuring device, characterized in that a value to be output is set. 3. The signal characteristic measuring device according to claim 1, wherein the data conversion means is constituted by a network structure of a plurality of processing units, and the internal state value is set between the processing units. A signal value to be output to an internal connection destination in accordance with the allocated internal state value, thereby realizing a data conversion function. apparatus. 4. The signal system characteristic measuring apparatus according to claim 1, wherein the data state of the signal located before the inspection data held by the storage means (11) is a specific state. A signal system characteristic measuring apparatus characterized in that it is configured as specified in an object.