JPH0247645Y2 - - Google Patents

Description

[Detailed description of the invention] This invention transmits ultrasonic waves toward the sea surface from a transducer installed on the ocean floor, and measures the time it takes for the ultrasonic waves to reflect on the sea surface and return to the transducer. However, when determining the wave height value by detecting the distance from the transducer to the sea surface, and therefore changes in the sea surface,
The wave height curve obtained by continuously recording the received signals of reflected waves records noise that includes frequency components that deviate from normal frequency components, in other words, the frequency components transmitted by the transducer. In some cases, the waveform does not exhibit a normal waveform pattern, but instead takes on an abnormal shape that includes fluctuations, resulting in the inconvenience of not being able to obtain accurate measurement results. , it is an object of the present invention to provide a noise removal device that deals with fluctuations that deviate from the normal pattern and performs a complementary operation to reduce errors as much as possible.

Next, embodiments will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of the embodiment, in which 1 is a waveguide, 2 is an analog multiplexer, 3 is an analog-to-digital converter, and 4 is a digital processing device.

Here, the type of wave device 1 does not matter. That is, either a low-frequency or high-frequency wave device may be used, and a band wave device may also be used.

Further, the digital processing device 4 uses a microcomputer or the like, and is used by incorporating a program necessary for data processing.

Figure 2 A shows the received waveform assuming that the received signal contains noise, etc., and N ₁ and N ₂
is noise with a relatively higher frequency component than the normal frequency, and N ₃ is noise close to the normal frequency component.
The dotted line shows the waveform when passed through a corrugator, and FIG. 2B shows the result of processing using the apparatus of the present invention.

In FIG. 1, when an analog signal A containing noise as shown by the solid line in _FIG . Noise N ₂
), and the envelope 〇a′ of the noise N ₃ is suppressed to become 〇b′.

Both the noise-suppressed signal B and the as-arrived signal A are applied to the analog multiplexer 2, where A and B are alternately switched and sent to the analog-to-digital converter 3. converted into a digital signal.

When the two types of signals converted into digital values by the analog-to-digital converter 3 are sent to the digital processing device 4, the digital processing device 4 samples the two signals almost simultaneously and generates a signal corresponding to the aforementioned signals A and B. Obtain digital values A' and B' and compare A' and B' to check whether they are substantially equal.

As a result of checking, if the data are of the same level, A′ is accepted as correct data and is imported. If the difference between the two is larger than the preset value, it is ignored and linear interpolation is performed to the next normal value. do.

In other words, when looking at N ₁ and N ₂ shown in Figure 2 A, the sampled value that includes noise (the shaded area) is compared with the sampled value that has been passed through a wave generator and the noise has been suppressed. Since the difference is large, N ₁
and N ₂ are treated as noise, and are eventually interpolated with a straight line as shown in Figure 2 (b).

Also, regarding N ₃ , the waveform b′ after passing through the waveform has a different phase and amplitude compared to the original waveform 〇a′, and the sampled values at the same time are different, so Linear interpolation is performed as shown in 〇c′ shown in Figure 2 (b).

As is clear from the above explanation, when noise is included in the received waveform that continuously tracks received signals, the present invention suppresses the amplitude of the noise through a waveform in the first stage, and suppresses the amplitude of the noise in the second stage. At the stage, the signal that has passed through the transducer,
Sample the signal that does not pass through the wave transmitter, compare both signals, and compare the difference with a preset value. If it deviates from the set value, it is treated as noise, and the value of the next arriving signal is Since it is configured to perform linear interpolation until it reaches a normal value, it is possible to correctly detect the desired signal value by eliminating the influence of noise.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment. FIG. 2 is an explanatory diagram of the operation. 1... Wave device, 2... Analog multiplexer, 3... Analog-to-digital converter, 4... Digital processing device.

Claims (1)

[Scope of utility model registration request] a waver to which an incoming analog received signal is applied; an analog multiplexer to which both the signal passed through the waver and the original analog signal are applied; and the two signals alternately switched by the multiplexer. and a digital processing device to which the two signals digitized by the analog-to-digital converter are applied, and in the digital processing device,
Sample the two applied signals separately and compare them, and if the difference is large beyond a preset value, treat it as noise and exclude it, and then draw a straight line until it becomes a normal signal. A device for removing noise contained in a recorded figure of a received signal.