JPH0226424B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention provides information processing using a phase pulse signal or a continuous frequency signal (for example, a ripple control signal) injected into a carrier AC voltage wave of a low-voltage power distribution line or dedicated line. This invention relates to improvements in signal transport methods for transmission.

(Background of the Invention) FIG. 10 shows a conventional phase pulse signal communication format. A repeater (terminal information collection device) connected to the central device injects a terminal selection signal 1 into the carrier AC voltage wave, and when the terminal detects the terminal selection signal 1, it sends a return signal 2 in response. Inject into the carrier alternating current voltage wave. When the repeater cannot receive the return signal 2 due to noise, the repeater retransmits the terminal selection signal 1, and the terminal also retransmits the return signal 2 accordingly. In this method, since the signals to be communicated are independent, signals that cannot be communicated are treated as unnecessary signals and are not subject to treatment.

In order to eliminate noise that causes communication failure,
The applicant has already proposed a signal detection method in which signals are averaged over a predetermined cycle. The communication format is shown in FIG. The repeater injects a terminal selection signal 3 containing a repeated address signal (terminal) over a predetermined number of cycles, and the terminal device responds to the terminal selection signal 3 by repeatedly injecting a return signal 4 containing a data signal a predetermined number of times. do. The number of times the return signal 4 is repeated is three times in FIG. 11, but in reality it is about several dozen times. This is because the injection circuit of the terminal has a small capacity that can only emit one phase pulse in one cycle.
This is because the return signal 4 is particularly susceptible to noise. The repeater performs signal detection by averaging the returned signals 4 to remove noise. In this method, the number of repetitions is determined based on the assumption of the worst-case transmission condition, so there is a problem in that the communication time becomes long.

(Objective of the Invention) An object of the present invention is to provide a signal transmission method capable of solving the above-mentioned problems and shortening the communication time under noisy conditions.

(Features of the Invention) In order to achieve this object, the terminal information collection device stores the undetectable return signal when the return signal from the terminal is undetectable, and
By injecting the same terminal selection signal again and averaging the return signal in response to the reinjected terminal selection signal with the previously stored transmission signal, the return signal is detected, thereby eliminating undetectable returns. The present invention is characterized in that signals are also effectively used for signal detection.

(Embodiments of the Invention) FIG. 1 is a diagram illustrating a signal transmission method of the present invention. A repeater corresponding to a terminal information collection device injects a terminal selection signal 5, and the terminal device injects a return signal 6 in response to this terminal selection signal 5. The repeater receives this return signal 6, and if it is able to detect the return signal 6 at this point, it injects a terminal selection signal for the next terminal. However, if the return signal 6 cannot be detected due to noise, the undetectable return signal 6 is stored and at the same time the same terminal selection signal 5 is injected again. When the return signal 6 in response is received, the stored previous return signal 6 and the current return signal 6 are added and averaged to detect the signal. Since random noise components are reduced by averaging, signal detection becomes easier.

If the signal cannot be detected even after averaging twice, the communication is repeated further. Even if the return signals 6 obtained through a predetermined number of communications, for example, five times, are added and averaged, if the signal cannot be detected, the stored return signal 6 is cleared and the process is restarted from the beginning.

In this way, when the S/N ratio is good, the return signal 6 is detected in one communication, and when the S/N ratio is poor, multiple communications are performed and multiple return signals 6 are detected. Since the return signal 6 is detected by the averaging of
Signals can be detected in the minimum necessary communication time even on noisy distribution lines.

An embodiment of the present invention in which a phase pulse signal is used as a signal will be described with reference to FIGS. 2 to 9.

FIG. 2 is a diagram illustrating channels set for the carrier AC voltage wave 7. FIG. Channels CH ₁ to CH ₁₂ having a predetermined phase angle width are set in a low noise region 8 which is a predetermined phase angle range around the zero point (0° or 180°) of the carrier AC voltage wave 7.
In the terminal selection signal sent from the repeater to the terminal, channel CH ₁ is the pilot channel, channel CH ₂ is the space channel, and channels CH ₃ to _{CH 12} are addresses representing binary codes 2 ⁰ to 2 ⁹ . assigned to each channel. In the return signal sent from the terminal to the repeater,
Channel CH ₁ becomes Space Channel, Channel CH ₂ becomes Pilot Channel, Channel
CH ₃ to _{CH 12} are assigned to data channels representing decimal codes 0 to 9, respectively.

FIG. 3 shows the configuration of the terminal selection signal Sa and the return signal Sb.

The terminal selection signal Sa is a carrier AC voltage wave 7 of 10.
cycles are used. The first cycle, the third
The cycle and the fifth cycle are space cycles in which no phase pulse signal is injected into channels CH ₁ to CH ₁₂ . The second cycle and the fourth cycle are synchronization cycles, and as shown in FIG. 4, the synchronization signal Sa ₁ is formed by injecting the phase pulse signal 9 into all address channels CH ₃ to _{CH 12} . be done. The 6th to 10th cycles are address cycles, in which the pilot channel CH ₁ and the address channel corresponding to the address code of the terminal (for example, in the case of a terminal at address 5 as shown in Fig. 4, address channels CH ₃ and
_{The address signal Sa 2 formed} by injecting the phase pulse signal 9 into the 6th to 10th
Sent repeatedly in cycles.

As the return signal Sb, 11 cycles of the carrier AC voltage wave 7 are used. The first and third cycles are space cycles, and channels CH ₁ ~
No phase pulse signal is injected into CH ₁₂ .
The second and fourth cycles are pilot cycles, and as shown in FIG. 5, the pilot signal Sb ₁ is formed by injecting the phase pulse signal 9 into the pilot channel CH ₂ . The 5th to 7th cycles are address cycles, which are formed by injecting the phase pulse signal 9 into the data channels corresponding to the ^102nd , ^101st , and ^100th positions of the terminal device's address code, respectively. Address signal Sb ₂ is sent out. The 8th to 11th cycles are data cycles, in which a phase pulse signal 9 is sent to the data channel corresponding to the 10 ^3rd , 10 ^2nd , 10 ^1st , and ¹⁰⁰ digits of the 4-digit data stored in the terminal.
The address signal Sb ₃ formed by injecting is sent out.

FIG. 6 shows a transmitting/receiving device in a repeater. The operation will be explained with reference to the flowcharts of FIGS. 7 and 8.

In step 1, the control circuit 10 controls the cycles and channels CH 1 to CH ₁₂ of the carrier AC voltage wave ₇ input from the input/output terminal 11 connected to the power distribution line.
is detected, and the injection circuit 12 is controlled to inject the terminal selection signal Sa over 10 cycles.

In step 2, the return signal Sb is received over 11 cycles. The return signal Sb is separated from the carrier AC voltage wave 7 by a filter 13, and the A/D
It is digitized by converter 14 and stored in memory 15. Digitization is performed, for example, by converting the level of each phase unit, which is obtained by subdividing one channel into a large number of units, into a digital value.

In step 3, it is determined whether the return signal Sb has been received a predetermined number of times (for example, five times).
If this is the first time, proceed to step 4.

In step 4, the control circuit 10 causes the arithmetic unit 16 to perform averaging, but since the previous return signal Sb is not stored in the first reception, the process proceeds to step 5 without performing averaging.

The signal detection routine of step 5 is shown in detail in FIG. In step 51, the value of the same channel of the space cycle is subtracted from the value of the channels CH ₁ to CH ₁₂ of the address cycle. This removes standing noise from address signal _Sb2 . Similarly, step 52 channels the data cycle.
Subtract the value of the same channel of the space cycle from the value of CH ₁ to CH ₁₂ . This allows the data signal
Stationary noise is removed from Sb ₃ . In step 53, it is determined whether the address signal Sb ₂ and data signal Sb ₃ from which standing noise has been removed contain only one phase pulse signal 9 in one cycle. If there is only one phase pulse signal 9 in one cycle, the process advances to step 54, and if there is zero or two or more phase pulse signals 9 in one cycle, it is determined that the signal cannot be detected and the process returns to step 1. Step 54 selects channels CH ₁ to _{CH 12} of the pilot cycle.
Subtract the value of the same channel of the space cycle from the value of . This removes standing noise from the pilot signal _Sb1 . In step 55, the waveform of the pilot signal Sb1 is subtracted from the waveform of the address signal _Sb2 , and in step 56 _, the waveform of the pilot signal _Sb1 is subtracted from the waveform of the data signal _Sb3 .
This subtraction can be a peak level subtraction,
It can also be done by subtracting the area. If the waveform difference is less than a predetermined value, a signal is determined to have been detected and is output from the output terminal 17 to a signal processing circuit (not shown) in step 6. If the waveform difference is greater than a predetermined value, it is determined that the signal cannot be detected and the process returns to step 1.

If the signal cannot be detected, return to step 1.
The routine repeats again. In step 4, the current return signal Sb and the previously stored return signal Sb are
are averaged, thereby reducing random noise. This averaging is repeated up to five times. If the return signal Sb is still not detected, the process proceeds to step 7 and it is determined that the signal cannot be detected. In step 6 and step 7, memory 1
The memory contents of 5 are cleared.

The transmitting and receiving device of the terminal device is similar to the transmitting and receiving device of the repeater shown in FIG. However, the injection circuit is 1
Only one phase pulse signal 9 is injected in a cycle.

FIG. 9 shows the operation of the transmitter/receiver of the terminal. In step 11, the difference between the synchronous cycle, which is the second cycle, and the space cycle, which is the first or third cycle, of the terminal selection signal Sa is calculated, and the difference between the synchronous cycle, which is the fourth cycle, and the third or fifth cycle, is calculated. Calculate the difference between the space cycle and the space cycle. In step 12, channel CH ₃ ~
Calculates the average of CH ₁₂ . This results in
Stationary noise and random noise are removed.
In step 13, the previous inter-channel addition average value stored in memory is compared with the current inter-channel addition average value, and if the current value is larger, the synchronization signal is
The process proceeds to step 14 assuming that Sa ₁ has been detected; otherwise, the process returns to step 11, assuming that the synchronizing signal Sa ₁ has not been detected. When proceeding to step 14, the memory as the previous inter-channel arithmetic average value is retained as is, and when returning to step 11, the previous inter-channel arithmetic average value is updated to the current inter-channel arithmetic average value.

In step 14, the average of the address cycles received and stored over five cycles is calculated. Then, in step 15, the difference between the average address cycle and space cycle is calculated.
In step 16, the address signal _Sa2 is detected by level verification or waveform verification. If detected, the process proceeds to step 17; if not detected, the process proceeds to step 11.
Return to In step 17, it is determined whether or not the address indicated by the address signal _Sa2 matches the address of the terminal device. If they match, the return signal Sb is sent out in step 18, and then the process returns to step 11.
If the addresses do not match, proceed immediately.
Return to 11.

(Modification) When using a leased line with relatively low noise, the terminal selection signal may consist of only an address signal, and the return signal may consist of an address signal and a data signal, or only a data signal. good. Alternatively, a digit designation signal may be added. In this case, the data signal of the return signal is only the data signal of the designated digit.

The return signal is not limited to one having only one pulse per cycle.

The number of cycles of the terminal selection signal and the number of cycles of the return signal are not limited to 10 cycles and 11 cycles, for example, each may be 1 cycle, or if it is possible to set a large number of channels in 1 cycle. Alternatively, the terminal selection signal and the return signal may be placed in the same cycle.

Storage and calculation are not limited to digital values, but may also be performed using analog values.

(Effects of the Invention) As explained above, according to the present invention, when the return signal from the terminal device is undetectable, the terminal information collection device stores the undetectable return signal, and
By injecting the same terminal selection signal again and averaging the return signal in response to the reinjected terminal selection signal with the previously stored transmission signal, the return signal is detected, thereby eliminating undetectable returns. Since signals are also effectively used for signal detection, communication time can be shortened under noisy conditions.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the signal transmission method of the present invention,
FIG. 2 is a diagram showing channel settings in an embodiment of the present invention, FIG. 3 is a diagram showing the configuration of a terminal selection signal and a return signal in an embodiment of the invention, and FIG. 4 is a diagram showing the configuration of a terminal selection signal and a return signal included in the terminal selection signal. A diagram showing the various signals that are
Fig. 5 is a diagram showing various signals included in the return signal, Fig. 6 is a block diagram showing the transmitting/receiving device of the repeater, Figs. 7 and 8 are flowcharts showing the operation of the repeater, and Fig. 9 is a FIGS. 10 and 11 are flowcharts showing the operation of the terminal, and are diagrams illustrating two examples of conventional signal transmission methods. 5...terminal selection signal, 6...return signal, 7...
Carrier AC voltage wave, 8...Low noise area, 9...
Phase pulse signal, 10... Control circuit, 11... Input/output terminal, 12... Injection circuit, 13... Filter, 14... A/D converter, 15... Memory, 1
6... Arithmetic unit, 17... Output terminal, CH ₁ to _{CH 12}
...Channel, Sa...Terminal selection signal, Sb...
Return number.

Claims (1)

[Claims] 1. In a signal transport method in which a terminal information collection device injects a terminal selection signal into a carrier AC voltage wave, and a terminal device injects a return signal in response to the terminal selection signal, the terminal information collection device If the return signal is undetectable, the undetectable return signal is stored, the same terminal selection signal is reinjected, and the return signal in response to the reinjected terminal selection signal is averaged with the previously stored return signal. By the way,
A signal transmission method characterized by detecting a returned signal.