JPH0636238B2 - Signal transmission line monitoring device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission line monitoring device used in a home automation system.

2. Description of the Related Art Conventionally, in home automation, a so-called power line carrier communication system is used in which an electric power line of 100 V AC is used together with a signal transmission path. The form of the communication signal is, as shown in FIG. 7 (a), data "1" when the high frequency signal is superposed on the intermediate point of the first half of each half cycle of AC 100V, and the high frequency signal is on the intermediate point of the second half. This is a kind of digital signal transmission method in which the state of superposition is regarded as data "0" and is called pulse position modulation. For example, as data '10
When trying to transmit 010 ', there is a relationship between AC 100V and a high frequency signal as shown in FIG. 7 (b). As shown in FIG. 6, as a signal transmission line monitoring device which is a simple means for pursuing the cause of defects in this type of system, as shown in FIG. 6, a receiving means 2 which is connected to the signal transmission line 1 and constantly receives a signal, and the reception result is notified. It was a combination with the notification means 3.

Problems to be Solved by the Invention In such a conventional configuration, periodical fluctuations on the signal transmission path, for example, fluctuations in impedance, communication failure due to distortion or loss of the signal waveform due to noise, etc., cannot be detected.

The present invention solves the problems as described above, and makes it possible to extremely easily investigate the cause of the above-mentioned failure in the communication system.

Means for Solving the Problems The present invention newly provides phase detecting means for generating a certain phase relationship with respect to a specific reference signal relating to communication on a signal transmission path. The phase detecting means operates the receiving means or the notifying means only at a specific phase.

Function The phase detecting means operates the receiving means or the notifying means only in a specific phase to detect a communication failure such as noise or impedance drop.

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

In FIG. 1, reference numeral 1 is a signal transmission path, to which a receiving means 2 and a phase detecting means 4 are connected together. Reference numeral 3 is an informing means for emitting sound, emitting light, shaking a pointer, etc., depending on the presence or absence of the received signal of the receiving means 2 or its intensity. The phase detecting means 4 generates a phase filter signal with respect to a specific reference signal related to communication on the signal transmission path 1, and limits the operation of the receiving means 2 only to the time period when the phase relationship is established. Is.
Then, the notification means 3 emits light according to the reception result of the reception means 2.
A notification operation is performed by sound or shaking of the pointer.

Although FIG. 2 shows another embodiment, it differs from FIG. 1 only in that the phase filter signal generated by the phase detection means 4 is added to the notification means 3 and the notification operation is performed only during the phase filter signal generation period. Others are the same. In the embodiment shown in FIGS. 1 and 2, the phase detecting means 4 can arbitrarily change the phase position with respect to the reference signal. The phase detecting means 4 can be realized by, for example, the configuration shown in FIG. In FIG. 8, 41 is a full-wave rectifier that full-wave rectifies the AC power supply voltage of the signal transmission line 1, 42 and 43 are first and second resistors that divide the output of the full-wave rectifier 41, and 44 is a divided voltage. Comparing the rectified voltage and the reference DC voltage to determine the 0V point of the AC power supply voltage, 45 starts by receiving the output of the comparator 44, and the operation time changes according to the delay amount data input from the outside. Variable timer,
Reference numeral 46 denotes a delay device that receives the output of the variable timer 45 and further adds a delay amount of a fixed time width, and 47 performs an exclusive OR operation of the output of the variable timer 45 and the output of the delay device 46 and outputs a phase filter signal. It is an exclusive OR.

The operation of the phase detection means 4 will be described with reference to the time waveforms of the signals of the respective parts in FIG. 9. The reference DC voltage Vr is applied to one of the input terminals of the comparator 44, and the divided AC voltage is applied to the other. A power supply rectified voltage is applied and an output pulse shown in FIG. 9B is obtained when the reference DC voltage Vr is higher. This pulse signal indicates the 0V point of the AC power supply voltage. The variable timer 45 outputs the pulse shown in FIG. 9C, which starts from the 0V point of the AC power supply voltage and stops after an arbitrarily set operation time. As a variable timer, for example, 1 MHz
If a 14-stage binary counter that can preset data is used as the clock input of
It is variable up to about 16 milliseconds in units of microseconds, and the position of the phase filter signal can be determined with such accuracy. The delay device 46 charges the capacitor 463 via the diode 461 immediately after the output pulse of the variable timer 45 is output, and discharges the capacitor 463 via the third resistor 462 when the output pulse of the variable timer 45 disappears. Shaper 464 of the potential change waveform of 463
The rectangular wave shown in FIG. 9 (e) is shaped by. The exclusive OR 47 performs an exclusive OR operation between the output of the variable timer 45 and the output of the delay device 46, and outputs the difference signal between them, that is, the output of the delay device 46 after the output of the variable timer 45 disappears. The phase-filtered signal that exists only until disappears is output as shown in FIG. The values of the third resistor 462 and the capacitor 463 are determined so that the time width of this phase filter signal is the same as or shorter than the time width of the data "1" and the data "0" of FIG. 7 (a). Has been.

Now, as shown in FIG. 3, the first device 1 is connected via the signal transmission path 1.
2 and the second device 13 constitute a communication system. At this time, the signal transmission path monitoring device 11 composed of the constituent elements shown in FIG. 1 or 2 is connected as shown in the figure to monitor the communication status between the devices 12 and 13. If noise is placed on the transmission line 1 or the line impedance is drastically reduced, communication cannot be performed.

For example, it is assumed that a noise generating device such as a discharge lamp is connected to the power line, that is, the signal transmission line, in the case of a power line carrier system in which the signal transmission line 1 and the power line are shared. If this system performs communication in synchronization with the power supply waveform, this power supply waveform becomes the reference signal of the system.

Then, as shown in FIG. 4, a noise waveform and a transmission signal c are generated in a specific phase portion with respect to the power supply waveform a. However, in some cases, both of them may be reception signals that cannot be distinguished on the reception side.

At this time, the phase detection means 4 on the signal transmission line monitoring device 11
Is adjusted to shift the phase filter signal e and monitor a portion where there is no original signal, only the noise can be captured and notified to the output of the signal transmission line monitoring device, and the cause of the communication failure can be investigated. That is, since the phase position where the communication signals of data "1" and "0" do not exist is monitored, if there is any notification at this time, the cause of the notification is noise.

Moreover, as shown in FIG.
If a device having a power supply block consisting of a capacitor 23 and a capacitor 23 is connected to the power line carrier system, voltage waveforms and current waveforms as shown in FIGS. Further, the impedance of the signal transmission line 1 decreases only in the specific phase portion as shown in FIG. As a result, a part of the transmitted signal e is greatly attenuated and transformed into a received signal, so that the signal cannot be received. At this time, since the portion where the communication signal can exist with respect to the power supply voltage waveform is originally known, it is possible to specify the position of the phase filter signal, and the transmission data “1” can be specified. It is not possible to say only "" or "0", and since "1" and "0" are always mixed, when the position of the phase filter signal is set at the position of data "1" or in the vicinity thereof. Even if there is only data "0" at one moment and there is nothing at the position to be observed, data "1" is always generated at another moment, so operate the device 12 or 13 to communicate. If there is no impedance failure, there should be a notification, but if there is a decrease in impedance, the phase detection means 4 on the signal transmission line monitoring device 11 is adjusted to shift the phase filter signal. As you, since the missing signal portions to a naturally if signal, as shown in FIG Ji, its output is eliminated. (Although it is originally reported, it is not reported.) Therefore, it is understood that the impedance is lowered in this phase part,
It is possible to take measures such as removing the obstacle.

EFFECTS OF THE INVENTION As described above, according to the present invention, by providing the phase detecting means, the cause of failure in the communication system can be extremely easily investigated, which is very useful in practice.

[Brief description of drawings]

1 and 2 are block diagrams showing different embodiments of the present invention, FIG. 3 is a block diagram showing an example of using the device of the present invention, and FIGS. 4 and 5 show the principle of pursuing the cause of communication failure. FIG. 6 is a block diagram showing a conventional example, FIG. 7 is a communication signal form diagram of a conventional home automation, FIG. 8 is a circuit diagram of a phase detecting means of the present invention, and FIG. 9 is a diagram of the present invention. It is a timing diagram of each part of the phase detection means. 1 ... Signal transmission path, 2 ... Receiving means, 3 ... Notification means,
4 ... Phase detection means.

Claims (2)

[Claims] 1. Receiving means connected to a signal transmission line for receiving a signal, notifying means for emitting sound, emitting light, shaking a pointer, etc. according to the presence or absence of a received signal of the receiving means or intensity, and a signal. A signal transmission path comprising a phase detection means for giving a certain phase relationship to a specific reference signal related to communication on the transmission path and limiting the operation of the reception means or the notification means only to the time period when the phase relationship is established. Monitoring equipment. 2. The signal transmission line monitoring apparatus according to claim 1, wherein the phase detecting means can arbitrarily change the phase position with respect to the reference signal.