JPH0120573B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a phase pulse signal transmission method for transmitting information between a terminal device and a repeater using a phase pulse signal injected into a carrier AC voltage wave of a low-voltage distribution line or the like. It is about improvement.

This phase pulse signal transmission method is suitable for automatically reading electricity meters installed at each customer and centrally controlling loads.
In the conventional phase pulse signal transmission method, as shown in FIG.
When the terminal device receives the terminal selection phase pulse signal 2 that matches its own address code, it injects the return phase pulse signal in the second cycle of the AC voltage wave 1. Alternatively, as shown in FIG. 2, the terminal device would inject a return phase pulse signal 3 into a different channel within the same cycle as the terminal selection phase pulse signal 2. That is, the first to second
As shown by the dotted arrow in the figure, the terminal device always returned one return phase pulse signal 3 in response to one terminal selection phase pulse signal 2.
Therefore, if the condition of the low-voltage distribution line is poor, such as when there is a lot of randomly generated noise or stationary noise, the terminal device cannot receive the terminal selection phase pulse signal 2 due to the cycle. As a result, there are scattered cycles in which the return phase pulse signal 3 is not returned, causing a problem of transmission errors.

An object of the present invention is to solve the above-mentioned problems, and to ensure and relatively easily communicate phase pulse signals between a repeater and a terminal even when there is a lot of noise in the carrier AC voltage wave. It is an object of the present invention to provide a phase pulse signal conveying method that can be carried out.

In order to achieve this object, the present invention detects noise in the carrier AC voltage wave at the latest before the repeater receives the return phase pulse signal and at the latest before the terminal device receives the terminal selection phase pulse signal. A predetermined number of cycles are performed to obtain the average noise level for the predetermined number of cycles, and the repeater injects a phase pulse signal for terminal selection over a predetermined number of cycles, and the terminal device injects a phase pulse signal for terminal selection that matches its own address. When a predetermined number of cycles are detected by comparing the signal with the average noise level, a return phase pulse signal is injected over a predetermined number of cycles, and the repeater compares the return phase pulse signal from the terminal with the average noise level. This feature is characterized in that both the repeater and the terminal perform time axis error testing.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 3 shows an embodiment of the present invention, in which a repeater and a terminal monitor the state of an AC voltage wave 1 prior to communicating phase pulse signals, and transmit information such as noise for a predetermined number of consecutive cycles S. to find the average noise level. Thereafter, the repeater injects the pilot signal 4 and the terminal selection phase pulse signal 2 over a predetermined number of cycles S. As shown in Fig. 4, the phase pulse signal carrying range 5 is defined in the low noise region near the zero cross, and 11 channels are provided.
Assuming that it is divided into CH1 to CH11, a pilot signal 4 with code "1" is injected into pilot channel CH1, and a terminal selection phase pulse signal 2 representing a coded address is injected into channels CH2 to CH9, respectively.

The terminal device monitors channels CH1 to CH9 over a predetermined number of cycles S, performs time axis error testing by comparing it with the average noise level, and selects a terminal that matches the pilot signal 4 and its own address code. When the phase pulse signal 2 is detected, a decimal code return phase pulse signal 3 is injected into the channels CH2 to CH11 over a predetermined number of cycles S. The repeater detects the returned phase pulse signal 3 by monitoring it over a predetermined number of cycles S and checking for errors on the time axis by comparing it with the average noise level.

FIG. 5 shows an example of a terminal device for implementing the present invention. Figure 6 is the time chart.

Prior to communication of the phase pulse signal, the repeater and the terminal monitor the AC voltage wave 1, but in the terminal, the filter 7 detects the AC voltage wave 1 input to the input terminal 6 from the AC voltage wave 1 in the same frequency band as the phase pulse signal. Separate the nozzle. The A/D converter 8 converts the noise level into a digital value for each phase unit obtained by further subdividing one channel according to a command from the control circuit 9.
Memory 10 stores these digital values.
After this, when the repeater injects the pilot signal 4 and the phase pulse signal 2 for terminal selection over a predetermined number of cycles S, the filter 7 separates these signals 4 and 2, including noise, from the AC voltage wave 1,
The A/D converter 8 converts each phase unit into digital values, and the memory 10 stores these values. The arithmetic circuit 11 first averages the noise level and reception level stored in the memory 10 over a predetermined number of cycles S. As a result, the random noise component in the noise (not synchronized with the phase) converges to zero, so the average noise level becomes that of the stationary noise component (synchronized with the phase), and the average received level becomes the stationary noise component (that is synchronized with the phase). The image contains only natural noise components. Next, the arithmetic circuit 11 subtracts the average noise level from the average reception level. This removes the stationary noise component and extracts only the phase pulse signal component. Note that the noise level may be subtracted from the reception level and then averaged.

By detecting pilot signal 4 on pilot channel CH1, the following channel
The phase pulse signal detected by CH2 to CH9 is determined to be the terminal selection phase pulse signal 2, and the address code determination circuit 12 determines whether the address code of the terminal selection phase pulse signal 2 matches its own address code. determine whether When they match, the phase pulse signal generating circuit 13 injects a return phase pulse signal 3 corresponding to the data into the AC voltage wave 1 over a predetermined number of cycles S.

The receiving section of the repeater is also similar to the circuit shown in FIG. 5, and detects the return phase pulse signal 3 through similar storage and calculation.

Note that, as shown in FIG. 7, monitoring of the AC voltage wave 1 of the repeater may be performed between the transmission of the relay and the transmission of the terminal. In the example of FIG. 4, channels CH2 to CH9 are used for terminal selection and return, but the number of channels may be increased and separate channels may be set. In that case, it is also possible to omit the pilot channel and pilot signal 4. If the arithmetic circuit 11 is of an analog type, the A/D converter 8 is unnecessary. The predetermined number of cycles S is preferably 10 to 100, but is not limited to this number.

As explained above, according to the present invention, the repeater detects noise in the carrier AC voltage wave at the latest before receiving the return phase pulse signal, and the terminal device detects noise in the carrier AC voltage wave at the latest before receiving the terminal selection phase pulse signal. A predetermined number of cycles are performed to obtain the average noise level for the predetermined number of cycles, and the repeater injects a phase pulse signal for terminal selection over a predetermined number of cycles, and the terminal device injects a phase pulse signal for terminal selection that matches its own address. When a predetermined number of cycles are detected by comparing the signal with the average noise level, a return phase pulse signal is injected over a predetermined number of cycles, and the repeater compares the return phase pulse signal from the terminal with the average noise level. Since both the repeater and the terminal perform error verification on the time axis, even if there is a lot of noise in the carrier AC voltage wave, the repeater and the terminal It is possible to reliably communicate phase pulse signals between the two. Also,
Compared to constantly detecting the average noise level when there is no signal, it is easy to detect the average noise level only in a predetermined number of cycles, so it is relatively easy to communicate phase pulse signals when there is a lot of noise. It can be carried out.

[Brief explanation of drawings]

Figures 1 and 2 are waveform diagrams showing a conventional phase pulse signal transport method, Figure 3 is a waveform diagram showing a phase pulse signal transport method of the present invention, and Figure 4 shows an example of channel settings in the present invention. 5 is a block diagram showing an example of a terminal device in which the present invention is implemented, and FIGS. 6 and 7 are time charts showing two examples of its operation. 1... AC voltage wave, 2... Phase pulse signal for terminal selection, 3... Phase pulse signal for return, 7... Filter, 8... A/D converter, 10... Memory,
11... Arithmetic circuit, 12... Address code discrimination circuit, 13... Phase pulse transmission circuit, S... Predetermined number of cycles, CH1 to CH11... Channel.

Claims (1)

[Claims] 1 A phase pulse signal in which a repeater injects a terminal selection phase pulse signal into a carrier AC voltage wave, and a terminal device injects a return phase pulse signal into the carrier AC voltage wave in response to the terminal selection phase pulse signal. In the carrier method, the repeater detects noise in the carrier AC voltage wave for a predetermined number of cycles at the latest before receiving the return phase pulse signal, and the terminal device detects the noise in the carrier AC voltage wave for a predetermined number of cycles before receiving the terminal selection phase pulse signal. After obtaining the average noise level for several cycles, the repeater injects the phase pulse signal for terminal selection over a predetermined number of cycles, and the terminal device injects the phase pulse signal for terminal selection that matches its own address to the average noise level. When a predetermined number of cycles are detected by comparison, a return phase pulse signal is injected over a predetermined number of cycles, and the repeater detects the return phase pulse signal from the terminal by comparing it with the average noise level. A phase pulse signal transport method characterized by: