JPH0718710B2 - Signal correction circuit - Google Patents

Description

The present invention relates to a correction circuit for an input signal, and more particularly to a correction circuit for an input signal regardless of the magnitude of the input signal, that is, the rise and fall inclination angle of the input signal. The present invention relates to a signal correction circuit that detects a width accurately and quickly.

[Prior Art] As an example of a conventional input signal rise width detection circuit, a high level is output when an input signal, which is an oversaturation signal, reaches a predetermined threshold level, and this is used as a rise position. When the voltage falls below the threshold level, the high level is stopped, this is used as the falling position, and the interval between the rising position and the falling position is detected as the rising width, or a fixed correction is added to this measured value. The circuit is known.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, for example, when the input signal of the supersaturation signal is a width signal in the measurement of the steel plate width during hot rolling, the supersaturation signal has a large value depending on the temperature of the steel plate and the like. Well,
That is, the rising inclination angle and the falling inclination angle change. Therefore, even if the supersaturation signal rises from the same position, the position triggered by a predetermined threshold level changes due to the temperature of the steel sheet and the like, which causes a measurement error.

There is also a circuit that automatically corrects the rising and falling slopes in an analog manner, but this has a problem that the response speed is slow.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problem of the conventional input signal rise width detection circuit, and is a signal correction for accurately and quickly detecting the rise width regardless of the size of the input signal. The purpose is to provide a circuit.

[Means for Solving Problems] The present invention has the following structural features for solving the above problems. That is, according to the present invention, as shown in FIG. 6, a first threshold circuit A for waveform-shaping an input signal at a threshold level VT ₁ and a second threshold circuit A for waveform-shaping an input signal at a threshold level VT ₂ higher than the threshold level VT ₁ . A threshold circuit B, a gate circuit C that outputs the difference between the output of the first threshold circuit A and the output of the second threshold circuit B, a clock pulse generation circuit D that generates a clock pulse, and the clock pulse. A first counting circuit E that counts the output of either the first or second threshold circuit, a second counting circuit F that counts the output of the gate circuit C by the clock pulse, and a second counting circuit F. The second counting circuit by multiplying the count value of 1 by the ratio between the first threshold level and the difference between the first and second threshold levels. Obtain a correction count value of the count value, and consists of a calculation processing unit G for adding the count value of the corrected count a first counting circuit E.

Therefore, according to the present invention, the count value of the second counting circuit F corresponding to the period from the reaching of the first threshold level to the reaching of the second threshold level includes the first threshold level and the first and second threshold levels. Multiplying the ratio with the difference, the count value of the second counting circuit corresponding to the output of the difference between the first and second threshold circuits corresponds to the count value from the rising point to the first or second threshold level. By obtaining the corrected count value and adding the corrected count value and the count value of the first counting circuit corresponding to the range exceeding the first or second threshold level, the rising or falling position of the input signal is calculated. Can be accurately detected.

[Embodiment] As shown in FIG. 1, an embodiment of the present invention is adopted in a steel plate width detection device 2 for measuring a width L1 of a strip steel plate 1 moving in a direction perpendicular to the drawing. Is. The steel plate width detection device 2 scans the steel plate 1 by swinging the measurement optical axis 4 in the direction of the arrow in FIG. Then, the front end portion 6 and the rear end portion 8 are detected, and the clock pulse output within the scanning time from the front end portion 6 to the rear end portion 8 is counted, whereby the width L1 of the steel plate 1 is
Is calculated.

A block diagram of the circuit of this embodiment is shown in FIG. 2, and a waveform diagram is shown in FIG. In FIG. 2, the input signal input to the amplifier circuit 100 is amplified into a supersaturated signal, which is output to the first threshold circuit 102 and the second threshold circuit 104.

The second threshold circuit 104 converts the amplified oversaturated signal into a square wave by the threshold level VT ₂ , which is then converted into a square wave by the first AND gate circuit 106 and the exclusive OR circuit 1.
Output to 08. The clock pulse generator 112 generates a clock pulse having a frequency high enough to measure the output pulse width of the first AND gate circuit 106 and the second AND gate circuit 114, and outputs the clock pulse to the first AND gate circuit 106 and the second AND gate circuit. 1
Output to 14.

The first AND gate circuit 106 performs a logical product operation of the square wave output of the second threshold circuit 104 and the clock pulse output of the clock pulse generator 112, and the number corresponding to the period T ₀ during which the oversaturation signal exceeds the threshold level VT _2. And outputs the clock pulse to the first counting circuit 118.

The first counting circuit 118 counts the output pulse of the first AND gate circuit 106 and outputs the result to the arithmetic processing circuit 116.
The first counting circuit 118 clears the count value each time one scan is completed by the input of a reset signal from a scan detector (not shown).

The first threshold circuit 102 converts the amplified oversaturated signal into a square wave according to the threshold level VT ₁ and outputs it to the exclusive OR circuit 108 and the fall detection circuit 110. Threshold level VT1 is set lower than the threshold level VT _2.

The exclusive OR circuit or EXOR gate circuit 108 is
The output of the threshold circuit 102 and the output of the second threshold circuit 104 are logically ANDed to form a pulse corresponding to the period ΔTu, ΔTd while the oversaturation signal is between the first threshold level VT ₁ and the second threshold level VT _2. Then, this is output to the second AND gate circuit 114.

The second AND gate circuit 114 takes the logical product of the output of the exclusive OR circuit 108 and the clock pulse output from the clock pulse generator 112, and outputs the pulse corresponding to the periods ΔTu and ΔTd to the second counting circuit 120.

The second counting circuit 120 counts the output pulse of the second AND gate circuit 114, that is, the one corresponding to the sum of the pulses input in the periods ΔTu and ΔTd, and outputs the counted value.
Output to 116.

The fall detection circuit 110 detects the fall of the output of the first threshold circuit 102 and outputs it to the arithmetic processing circuit 116.

The arithmetic processing circuit 116 includes a first counting circuit 118 and a second counting circuit 120.
The period from the output to the rising point to the falling point of the oversaturation signal is obtained by arithmetic processing, which will be described in detail later.

The output of the arithmetic processing circuit 116 is output to the display 122 and displayed as the width value of the strip steel plate. The output of the arithmetic processing circuit 116 is used as a width control signal by feeding back to the steel plate manufacturing section as desired.

As shown in FIG. 4, in the flowchart of the arithmetic processing circuit 116, the presence or absence of the fall detection pulse is detected in the first step to determine whether or not the arithmetic processing is performed. If there is no fall detection pulse, the detection routine is repeated, and if there is a fall detection pulse, the process proceeds to the next step.

The second step is the output of the first counter circuit 118, i.e. read pulse count T0 supersaturation signal corresponds to the threshold level VT ₂ greater than the period.

The third step is the output of the second counting circuit 120, that is, the period ΔTu during which the oversaturation signal rises from the threshold level VT ₁ to VT ₂ and the threshold level VT ₂ when falling.
Read the sum (ΔTu + ΔTd) of the period ΔTd from reaching to VT ₁ .

The fourth step was read in the third step (ΔTu + ΔT
Multiply d) by a constant K to be described later, and the period in which the threshold level VT ₁ is reached from the rising point when the oversaturation signal rises, and the threshold level when falling.
The sum K (ΔTu + ΔTd) of the period from VT ₁ to the falling point is calculated.

In the fifth step, the sum {T ₀ + K (ΔTu + ΔTd)} of the count value T ₀ read in the second step and the calculation in the fourth step is calculated.

The sixth step is the calculation result of the fifth step {T ₀ + K
(ΔTu + ΔTd)} is output.

In the seventh step, it is judged whether or not the measurement is completed. If the measurement is not completed, the procedure returns to the first step, and if it is completed, END is set.

The constant K in the fourth step of the arithmetic processing circuit 116 will be described below. In FIG. 5, the horizontal axis represents the period T and the vertical axis represents the voltage level V, and supersaturation signals A and A'and threshold levels VT ₁ and VT ₂ are shown. Oversaturation signal A, A ′
Is the detection signal of the tip of the same steel sheet, and the magnitudes of the supersaturation signals, that is, the rising inclination angles differ depending on the temperature difference between the steel sheets, but their estimated rising points 0 are constant. The present invention detects the estimated rising point 0 as the end portion of the steel sheet or the like.

The period until the supersaturation signals A and A ′ reach the threshold level VT ₁ to VT ₂ is ΔTu and ΔTu ′ as described above. Here, let Tu, Tu 'be the period until the oversaturation signal A, A' reaches the threshold level VT ₁ from the rising point 0. For the oversaturation signal A, VT ₂ / (Tu + ΔTu) = (VT ₂ −VT ₁ ) / DerutaTu That _{Tu + ΔTu = {VT 2 /} (VT 2 -VT 1)} becomes × ΔTu. Supersaturation signal A 'For, VT ₂ / (Tu' The _{+ ΔTu ') = (VT 2} -VT 1) / ΔTu' and That Tu '+ ΔTu' = {VT 2 / (VT 2 -VT 1)} × ΔTu ' Become. Therefore, from the rising point 0 to the threshold level
The period to reach VT ₂ is
A constant determined only by the threshold level {VT ₂ /
(VT ₂ −VT ₁ )} and the period ΔTu from the threshold level VT ₁ to reaching VT ₂ can be obtained, and K = VT ₂ / (VT ₂ −VT ₁ ). Although the above description is made for the rising edge, it is needless to say that the same consideration can be made for the falling edge. Thus, the constant K in the fourth step of the arithmetic processing circuit 116 becomes _{[VT 2 / (VT 2 -VT} 1)].

In the present embodiment, the output of the second threshold circuit 104, in other words, the signal corresponding to the width of the supersaturation signal exceeding the threshold level VT ₂ is counted by the second counting circuit 120, and the difference between the first and second threshold circuits is calculated. Multiply the count value of the second counting circuit corresponding to the output by the ratio of the difference between the threshold level VT ₁ and the threshold level VT ₁ and the threshold level VT ₂ , until the threshold level VT ₁ or VT ₂ is reached from the rising point. The correction count value corresponding to the count value of the
Since you are adding a 120 count value, the constant K as described above becomes _{VT 2 / (VT 2 -VT 1} ). Here, the count value of the second counting circuit 120 is the period T between the times when the oversaturation signal crosses the threshold level VT ₂ in FIG.
_The correction count value obtained by the constant K corresponds to Tu + ΔTu or Td + ΔTd during the period until the rising or falling point and the oversaturation signal cross the threshold level VT ₂ .

However, when the first counting circuit 118 is configured to count the signal corresponding to the output of the first threshold circuit 102, in other words, the width of the supersaturated signal exceeding the threshold level VT ₁ , it is clear from FIG. , T
u and Tu ′ correspond to the corrected count value. The relationship between Tu and ΔTu is Tu = {VT ₁ / (VT ₂ −VT ₁ )} × ΔTu, and the constant K is VT ₁ / (VT ₂ −VT ₁ ), as in the above embodiment. Become.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, the count value of the second counting circuit corresponding to the period from reaching the first threshold level to reaching the second threshold level is Alternatively, the correction count value corresponding to the period from the rising point or the falling point to the first or second threshold level is obtained by multiplying the ratio of the second threshold level and the difference between the first and second threshold levels. By adding the corrected count value and the count value of the first counting circuit corresponding to the range exceeding the first or second threshold level, accurate detection of the input signal from the rising position or the falling position can be performed. It has the effect that it can be done.

[Brief description of drawings]

FIG. 1 is an explanatory view of a steel plate width detecting device incorporating an embodiment of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, FIG. 3 is a waveform diagram of each point in the flowchart of FIG. FIG. 4 is a flow chart of the arithmetic processing circuit 116, FIG. 5 is an explanatory diagram for calculating the constant K used in the arithmetic processing circuit 116, and FIG. 6 is a configuration explanatory diagram of the present invention. 1 ... Steel plate 2 ... Steel plate width detecting device 4 ... Measuring optical axis 100 ... Amplifying circuit 102 ... First threshold circuit 104 ... Second threshold circuit 106 ... First AND gate circuit 108 ... Exclusive OR circuit 112 ... Clock pulse generator 116 ... Arithmetic processing circuit

Claims (3)

[Claims] 1. An input signal is fed to a first threshold level VT ₁
A first threshold circuit for shaping the waveform of the input signal, a second threshold circuit for shaping the waveform of the input signal at a second threshold level VT ₂ higher than the first threshold level VT _1, and an output of the first threshold circuit and the second threshold. A gate circuit that outputs a difference from the output of the circuit, a clock pulse generation circuit that generates a clock pulse, a first counting circuit that counts the output of the first or second threshold circuit by the clock pulse, and a clock pulse by the clock pulse. A second counting circuit for counting the output of the gate circuit, and a count value of the second counting circuit corresponding to a period from reaching the first threshold level to reaching the second threshold level, the first or second threshold level. And the difference between the first and second threshold levels are multiplied to obtain the From Ri point or falling point first
Alternatively, the correction count value corresponding to the period until the second threshold level is reached is converted into the correction count value and the first correction count value.
Alternatively, a signal processing circuit including: an arithmetic processing unit that adds a count value of the first counting circuit corresponding to a range exceeding the second threshold level. 2. The signal correction circuit according to claim 1, wherein the first counting circuit is configured to count the output of the first threshold circuit, and the corrected count value is the second counting circuit. The ratio of the first threshold level to the difference between the first and second threshold levels {VT
₁ / (VT ₂ −VT ₁ )} is multiplied and converted so as to correspond to the period from the rising point or the falling point until the first threshold level is reached, and the arithmetic processing unit has the corrected count value. And a count value of the first counting circuit corresponding to a range exceeding the first threshold level, the signal correcting circuit being configured to be added. 3. The signal correction circuit according to claim 1, wherein the first counting circuit is configured to count the output of the second threshold circuit, and the corrected count value is the second counting circuit. The ratio of the difference between the second threshold level and the difference between the first and second threshold levels {VT
₂ / (VT ₂ −VT ₁ )} is multiplied and converted so as to correspond to the period from the rising point or the falling point until the second threshold level is reached, and the arithmetic processing unit calculates the corrected count value. And a count value of the first counting circuit corresponding to a range exceeding the second threshold level.