JPS6256697B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for noise separation of a phase pulse signal, which separates a phase pulse signal injected onto an AC voltage wave of an AC distribution line or dedicated line from noise that is not synchronized with the phase such as white noise. It is about the method.

Conventionally, when receiving a phase pulse signal carried by an alternating current voltage wave on a distribution line or dedicated line, it is necessary to separate the white noise present in the alternating voltage wave from the necessary phase pulse signal. First, as shown in FIG. 1, noise levels 3 and 4 are measured prior to separation of phase pulse signals 1 and 2, and an average noise level is detected from these noise levels 3 and 4. A reception threshold level 5, which is higher than the average noise level, is set, and anything exceeding the reception threshold level 5 is determined to be a phase pulse signal. Noise that occurs randomly and exceeds the reception threshold level is separated from the phase pulse signal by determining whether it is a phase pulse signal or not by an integral test that counts the number of receptions within a unit time.

However, since the minimum value of reception threshold level 5 as described above cannot be set below the average noise level, the noise level may become equal to or higher than the level of the phase pulse signal, or When the phase pulse signal 2 is present in the following signal dead zone 6, there is a problem that the white noise and the phase pulse signal cannot be separated, and the phase pulse signal cannot be extracted.

An object of the present invention is to solve the above-mentioned problems, and also to provide a low-level phase pulse signal below the noise level.
It is an object of the present invention to provide a noise separation method for a phase pulse signal that can separate noise that is not synchronized with the phase.

To achieve this objective, the present invention subdivides each channel on an alternating voltage wave into which a phase pulse signal is to be injected into a plurality of phase units, and divides the received level in each phase unit over a predetermined number of cycles. If the added reception level value is greater than a predetermined value, it is determined that the reception level is due to the phase pulse signal,
The feature is that in each channel, a phase pulse signal that is synchronized with the phase and noise that is not synchronized are separated.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 2 shows an example of a phase unit according to the present invention.

The phase pulse signal carrying range 8 of the alternating current voltage wave 7 includes a channel into which the phase pulse signal is to be injected.
CH1 to CH20 are set. Each channel CH
1 to CH20 are further subdivided into phase units U1 to U10 that test the level of the phase pulse signal or white noise per unit time. Although one channel is subdivided into 10 phase units in FIG. 2, it is actually desirable to subdivide it into about 20 to 100 phase units (2 to 10 μs).

During reception, each channel CH1 to CH20
The phase pulse signal or white noise present in the phase pulse signal is separated from the AC voltage wave 7 by a receiving circuit described later, and the level in each phase unit U1 to U10 is repeatedly detected for n cycles.

For example, when a phase pulse signal exists in channel CH4, the first cycle phase pulse signal 9 shown by the solid line is detected, and each phase unit U
The level of the phase pulse signal 9 from 1 to U10 is collected as analog data _D1 of the first cycle. Analog data collection similar to the above is performed using the n-th cycle phase pulse signal 1 shown by the broken line.
This is repeated until 0 analog data D _o is collected. Phase pulse signals 9-10 are triggered synchronously with respect to channel CH4, so that the analog data collected as described above
The values of D ₁ to _{D o} for each phase unit U1 to U10 are always approximately equal. For example, -2 analog data is always collected in phase unit U3. On the other hand, white noise exists in all phases. For example, when detecting the white noise of channel CH17, in the same way as above, white noise 11 of the first cycle shown by the solid line (to avoid confusion in the drawing) Analog data D ₁ ′ to D _o ′ in each phase unit U1 to U10 from (schematically illustrated) to the n-th cycle of white noise 12 shown by a broken line are collected. The white noises 11 and 12 are distorted waves whose waveforms and levels always fluctuate randomly and are not synchronized with the phase.

Collected analog data _D1 ~ _Do , D1 _' ~D
_o ' for each phase unit U1 to U10 and divided by the number of cycles n, each phase unit U1 to U10 of analog data D ₁ to D _o of phase pulse signals 9 to 10 is obtained.
The average value in each phase unit _U1 -U10 of the analog data D1'- _Do ' of the white noises 11-12 ultimately converges to zero, whereas the average value in each phase unit U1-U10 of the white noises 11-12 remains constant. This is because the phase pulse signals 9 to 10 are repetitive and synchronized with the phase, whereas the white noises 11 and 12 are random and not synchronized with the phase.

FIG. 3 shows the same phase units U1 to U1 as in FIG.
0 shows an example in which a phase pulse signal and white noise are mixed.

Channel CH9 receives phase pulse signal 9' and white noise 11' in the first channel, and phase pulse signal 10' and white noise 1 in the nth cycle.
2', the levels in each phase unit U1 to U10 are detected for n cycles in the same way as the explanation in FIG.
Analog data D ₁ ″ to D _o ″ for each zero are collected.
When the values of the analog data C ₁ '' to C _o '' are added in each phase unit U1 to U10 and divided by the number of cycles n, the ratio of the phase pulse signal to the white noise (S/ N ratio)
data for each phase unit U1-U10 that is close to phase pulse signals 9'-10' synchronized with channel CH9 is obtained, and white noises 11'-12' are removed.

FIG. 4 shows an example of a noise separation circuit implementing the present invention.

The noise separation circuit is provided with a receiving circuit 14 and a control circuit 15, each connected to a connection terminal 13 with an AC power distribution line, and the receiving circuit 14 separates the phase pulse signal and white noise carried by the AC voltage wave 7. Receive. Control circuit 15 detects the phase angle of AC voltage wave 7 and controls other circuits accordingly.

The receiving circuit 14 is connected to a phase pulse signal output terminal 20 via an A/D conversion circuit 16, a memory circuit 17, an adder circuit 18, and a buffer memory circuit 19.

The operation will be explained below with reference to FIGS. 3 and 4.

Phase pulse signals 9'-10' carried by alternating voltage waves 7 and white noise 11'-12'
is noise-separated from the AC voltage wave 7 by the receiving circuit 14, and level detection is repeatedly performed from the first cycle to the nth cycle for each phase unit U1 to U10.

The values of the analog data C ₁ ″ to _{C o} ″ collected as a result of the level detection described above are converted into digital values by the A/D conversion circuit 16, and are converted into digital values as quantized data in the respective phase units U1 to U10.
It is stored in the memory circuit 17.

When level detection in each phase unit U1 to U10, collection of analog data _C1 '' to _C0 '', conversion to quantized data, and accumulation thereof from the first cycle to the nth cycle are completed, the control circuit 15 In response to the command, the adder circuit 18 operates to add the quantized data in each phase unit U1 to U10. Due to this addition, the quantized data based on the phase pulse signals 9' to 10' that are synchronized with channel CH9 becomes a value that exceeds a predetermined value regarding the number of cycles n, but it becomes a white noise that is not synchronized with channel CH9. Since the value of the quantized data based on this does not exceed a predetermined value, the phase pulse signals 9' to 1
The data of each phase unit U1-U10 of 0' can be noise-separated from the data of white noise mixed in the same phase unit U1-U10.

As described above, each phase unit U1-U10 of the phase pulse signals 9'-10' is separated from the white noise 11'-12' for each phase unit U1-U10.
The data is outputted via the buffer memory circuit 19 and the phase pulse signal output terminal 20 as phase pulse signals 9' to 10' of channel CH9. In each channel CH1 to CH20, the phase pulse signal and white noise are separated from each other in the same way as in channel CH9, and the phase pulse signal synchronized with each channel CH1 to CH20 is extracted regardless of the level. .

In addition, in FIG. 4, only addition is performed and division by the number of cycles n is not performed, but since the number of cycles n is predetermined to be a large number, the added value regarding the phase pulse signal is a predetermined value related to the number of cycles n. On the other hand, the added value for white noise becomes a value close to zero, and does not exceed a predetermined value.
This makes it possible to separate phase pulse signal data and white noise data.

FIGS. 5 to 7 show the results of experiments. White noise having the same frequency as the phase pulse signal is a distorted wave as shown in FIG. 5, and its waveform and level change randomly. Figure 6 is 0-200
The received waveform is shown when a phase pulse signal is injected in a time range of μs (the width of one channel is often set to 200 μs). Although this waveform is a combination of a phase pulse signal and white noise, the existence of a phase pulse signal cannot be detected from this waveform. FIG. 7 shows a waveform that has been averaged 250 times according to the present invention. The white noise has almost converged to zero, and the phase pulse signal is clearly visible.

The set numbers of channels CH1 to CH20 and phase units U1 to U10 for subdividing each channel CH1 to CH20 shown in FIGS. 2 and 3 are not limited to those shown in the figures. The number of times the level of each phase unit U1 to U10 is detected is set to w, and the greater the number of times, the more the noise separation accuracy between the phase pulse signal and white noise can be improved. It is also possible to add the analog data using an analog adder without converting it into quantized data, and extract the phase pulse signal based on the difference between the phase pulse signal and white noise.

As explained above, according to the present invention, each channel on an AC voltage wave into which a phase pulse signal is to be injected is subdivided into a plurality of phase units, and the reception level in each phase unit is adjusted over a predetermined number of cycles. Since the received level is determined to be the received level due to the phase pulse signal when the value of the added received level is equal to or higher than a predetermined value, even if the phase pulse signal has a low level below the noise level, it will also be considered to be a noise with out-of-phase synchronization. and can be separated.

[Brief explanation of the drawing]

FIG. 1 is a waveform diagram showing a general phase pulse signal and white noise, FIGS. 2 and 3 are diagrams showing phase units and reception levels for subdividing channels in the present invention, and FIG. 4 is a diagram showing the reception level for implementing the present invention. FIG. 5 is a waveform diagram of actual white noise, FIG. 6 is a composite waveform diagram of a phase pulse signal and white noise, and FIG. FIG. 2 is a waveform diagram of a phase pulse signal from which noise has been separated from FIG. 1, 2... Phase pulse signal, 3, 4... White noise, 7... AC voltage wave, 8... Phase pulse signal carrier range, 9, 9', 10, 10'... Phase pulse signal,
11, 11', 12, 12'...white noise, 1
4...Reception circuit, 18...Addition circuit, CH1 to CH20
... Channel, U1 to U10 ... Phase unit, D ₁ ,
D ₁ ′, D ₁ ″, D _o , D _o ′, D _o ″…Analog data.

Claims (1)

[Claims] 1 In a phase pulse signal noise separation method that separates noise that is not synchronized with the phase of an AC voltage wave, each channel on an AC voltage wave into which a phase pulse signal is to be injected is subdivided into multiple phase units, and each phase A phase pulse signal, characterized in that reception levels in units are added over a predetermined number of cycles, and when the value of the added reception level is equal to or greater than a predetermined value, it is determined to be a reception level due to the phase pulse signal. Noise separation method.