JP3007774B2 - Spike noise determination device and spike noise determination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spike noise judging device and a spike noise judging method.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional judgment method of this kind. That is, in FIG. 5, assuming that the concentration of the NO gas contained in the sample gas changes in an arbitrary pattern (not shown), such a sample gas is used as a CLA (Chemical Lumin-escence Analyzer).
: Chemiluminescent analyzer), a predetermined reaction is performed in the reaction cell together with the ozone gas, and light is emitted in proportion to the concentration of the NO gas. This light is received by the photo sensor 32,
The photocurrent emitted from this photosensor is supplied to the preamplifier 3
After passing through No. 3, a preamplifier output B as shown in FIG. It is assumed that spike noise SP is included in the preamplifier output.

Subsequently, the preamplifier output B is applied to the filter 3
4 and 35, and the filter 35 outputs an output F to the comparator 36 as shown in FIG. In this comparator, the output F is compared with a comparator level R. At this time, when the output F is smaller than the comparator level R, the comparator 3
Nothing is output from No. 6, and therefore, the NO gas concentration output from the filter 34 is continuously taken in. On the other hand, when the spike noise SP is mixed into the output F and the output F is larger than the comparator level R, the comparator 36
From the comparator output G as shown in FIG.
Is output. Thus, it has been determined that the preamplifier output B contains the spike noise SP. Reference numeral 37 denotes a reference power supply that defines the comparator level R.

FIG. 7 shows another determination method. That is, in FIG. 7, light proportional to the concentration of NO gas from the reaction cell 31
The photo sensors 41, 4
The outputs a and b of the same level are simultaneously output from the preamplifier 43,
When the spike noise SP is not generated, the subtraction output from the subtractor 45 is zero. By the way, if one of the outputs a and b of the photo sensors 41 and 42 changes, the subtraction output a−b
Is not zero, and this is compared by the comparator 46, whereby it is determined that the spike noise SP has occurred when the level becomes equal to or higher than the comparator level specified by the reference power supply 47.

[0005]

However, in the former spike noise determination method, the N contained in the sample gas is not included.
When the high-concentration NO gas is rapidly introduced into the reaction cell 31 together with the ozone gas depending on the change in the concentration of the O gas, and the rise becomes steep like the spike noise preamplifier output ((E) in FIG. 3, ( F)), it is difficult to distinguish between the preamplifier output of spike noise and that of NO gas concentration, and there is a possibility that spike noise is erroneously determined. In addition, since the comparator 36, the reference power supply 37, or a circuit for judging spike noise at the subsequent stage is required, the cost is reduced.

The latter is expensive since two sets of photosensors 41 and 42 and two preamplifiers 43 and 44 are used for the spike noise determination method.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to eliminate the influence of spike noise included in an amplifier output without erroneous determination and at a low cost. An object of the present invention is to obtain a spike noise determination device and a spike noise determination method.

[0008]

In order to achieve the above object, a spike noise determining apparatus according to the present invention comprises:
A photosensor that receives light in proportion to the concentration of the component gas to be measured that emits light when the sample gas is introduced into the reaction cell of the chemiluminescence gas analyzer together with the ozone gas, and amplifies the photocurrent emitted from the photosensor And an A / D converter for A / D converting the output of the amplifier.
D / D converter and calculates / processes the A / D converted value to spy
Start of Kunoizu generation and termination Ri Na <br/> from a processing unit to determine, further, the determination of the start time _{t n-1, t n,} t
A / D conversion value I at _{n + 1} (t _n-1 <t _n <t _{n + 1} )
(T _n−1 ), I (t _n ), I (t _{n + 1} )
On the other hand, the end determination is made at times t ′ _n−1 , t ′ _n (t _{n + 1
<T 'n-1 <t} ' n) in the A / D converted value I (t '
_{n-1), I (t} 'n) and the spike noise generation before the A
/ D conversion value I (t _n-1 ) .

The present invention also provides a method for determining spike noise using the above-described spike noise determination apparatus, wherein a component gas to be measured which emits light when a sample gas is introduced together with ozone gas into a reaction cell of a chemiluminescence gas analyzer. Amplifies the photocurrent emitted from the photosensor that receives light proportional to the density of the light, outputs the amplified current, and then A / D converts the signal to start and end spike noise generation according to the following criteria by the program of the arithmetic processing unit. And a spike noise determination method for determining the spike noise.

That is, time t _n−1 , t _n , t _{n + 1} (t
_{n-1 <t n <t} n + 1) , respectively A / D conversion value at _{I (t n-1),} I (t n), and I (t _{n + 1),} the determination level of the spike noise I _{Assuming d} , a. I (t _n )
If −I (t _n−1 ) <I _d , it is determined that the noise is not spike noise. If I (t _n ) −I (t _n−1 )> I _d , the following b. Column, b. If I (t _{n + 1} )> I (t _n ), it is determined that the noise is not spike noise, and I (t _{n + 1} ) <I
At (t _n ), it is determined that spike noise has started. On the other hand, the spike noise ends at times t ′ _n−1 , t ′ _n (t _{n + 1} <t ′ _n−1 <t ′ _n ). The A / D converted values are I (t ' _n-1 ) and I (t' _n-1 ), respectively.
(T _'n) and to, when the determination level of the spike noise and I _d, c. _{I (t 'n-1)} <I (t' n), or,
A spike noise determination method consisting in determining the case of _{I (t 'n) -I (} t n-1) <I d.

[0011] The present invention provides also for a you determine start and end of the spike noise generated by a program of the CPU what the amplifier output is at a concentration output of the measurement gas components converted A / D (processing unit) , or calculated each a / D conversion value with each other at different times, with or added to determine the level I _d of the a / D converter in an operation process, by determining whether or start and end of the spike noise Conventionally, it is difficult to distinguish the preamplifier output of spike noise from that of NO gas concentration, and there is a possibility that spike noise is erroneously determined. In order to avoid the problem that two sets of photosensors and preamplifiers are used for the spike noise determination method, the amplifier output is reduced. The effect of spike noise included in the image data can be removed at a low cost without any erroneous determination using an easy program and with a simple configuration including a photosensor, an amplifier, an A / D converter, and a CPU. Things.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited thereby. In FIG. 1, a spike noise determination device J is a component gas to be measured (NO in this embodiment) which emits light when a sample gas is introduced together with an ozone gas P into a reaction cell of a chemiluminescence gas analyzer (not shown). Photo sensor 1 for receiving light proportional to the concentration of gas (S)
And an amplifier 2 for amplifying and outputting a photocurrent emitted from the photosensor, an A / D converter 3 for A / D converting the amplifier output B ' , and calculating and processing the A / D converted value. And an arithmetic processing unit (CPU) 4.

Further, the component gas S to be measured is NO gas, the amplifier 2 is an amplifier having a time constant T of RC (R is a resistance value, C is a capacitance of a capacitor), and the A / D converter 3 is itself. , A / D conversion values I (t _n−1 ), I (t _n ), I (t _{n + 1} ) corresponding to the respective times t _n−1 , t _n , t _{n + 1.}
The presence of spike noise from having a determination level I _d which is determined by the arithmetic processing unit 4 with the desired program. In this embodiment, the integrated value within the sample time is used as the A / D conversion value.

Hereinafter, a spike noise determination method will be described. As shown in FIG. 2A, it is assumed that an amplifier output B 'due to a spike noise at a rising portion 2a as shown in FIG.

The result of the A / D conversion is processed by an arithmetic processing unit 4.
The start and end of the spike noise occurrence are determined by the following program based on the following criteria.

That is, in FIGS. 2C and 2D, times t _n−1 , t _n , t _{n + 1} (t _n−1 <t _n <
t _{n + 1} ), the A / D conversion values are
(T _n-1 ), I (t _n ), I (t _{n + 1} ), and the spike noise determination level is I _d , a. If I (t _n ) −I (t _n−1 )> I _d , it exceeds the decision level I _d , so it is determined that the noise is not spike noise, and I (t _n ) −I (t _n−1 ) < If I _d, below b.
Column, b. If I (t _{n + 1} )> I (t _n-1 ), it is determined that the noise is not spike noise. If I (t _{n + 1} ) <I (t _n ), A
Since the / D conversion value has decreased immediately after the increase, it is determined that spike noise has started.

Next, regarding termination of spike noise,
The A / D converted values at times t ' _n-1 and t' _n (t _{n + 1} <t ' _n-1 <t' _n ) are represented by I (t ' _n-1 ) and I (t' _n-1 ), respectively.
(T _'n) and to, when the determination level of the spike noise and I _d, c. In the case of _{I (t 'n-1)} <I (t' n) is, A / D
Since the conversion value has started to increase, it is determined that the spike noise has ended. Also, when the judgment level _Id is used,
Even if I (t ′ _n ) −I (t _n−1 ) <I _d, it is determined that the spike noise has ended because the difference between the A / D converted values has fallen below the determination level I _d .

As described above, in the present embodiment, the NO gas S emits light when mixed with the ozone gas P, and the light is received by the photosensor 1, and the time constant T is RC (R is the resistance value, C is the capacitance of the capacitor). After A / D conversion through amplifier 2, CP
At U4, the presence / absence of spike noise is determined by arithmetic processing. Since the amplifier output B ′ due to spike noise has a steep rise, a. And I (t _n ) −I
As (t _n-1 )> _Id , the increase in the A / D conversion value exceeds the spike noise determination criterion, but on the other hand, the high concentration NO gas is rapidly introduced into the reaction cell together with the ozone gas to emit light [ 3 (E)], the rise 5a of the amplifier output B ″ due to the change in the NO gas concentration is also the same as in FIG. 3 (F).
As shown in FIG. 3, since the spike noise becomes steep similarly to the amplifier output B ′, the A / D conversion value due to the change in the NO gas concentration becomes I ′ (t _{n + 1} )> I ′ from FIG. (T _n )
[I ′ (t _{n + 1} ) and I ′ (t _n ) are at time t
A / D conversion value of the NO gas concentration at _{n + 1} , t _n ], while the spike noise shows a subsequent change in the A / D conversion value from FIG. I
(T _{n + 1} ) <I (t _n ), it can be seen that the amplifier output B ′ of spike noise and NO
The gas concentration can be distinguished from the amplifier output B ″, and it can be easily determined that spike noise has started without erroneous determination.

Further, the end of the spike noise, A / D conversion value after the start spike noise spike noise before the start A / D conversion value to the added value obtained by adding the determined level I _d spike noise, I (t ' _n ) -I (t _n-1 ) <I _d , or the A / D converted value after the start of spike noise is I (t' _n-1 ) <I (t ' _n ) It can be easily determined as when the ascent starts.

As described above, the program as described above is relatively easy, and not only the start but also the end of spike noise can be accurately determined, so that the time for holding the output for removing spike noise can be shortened. In addition, the influence of spike noise included in the amplifier output is
With a simple configuration including the amplifier 2, the A / D converter 3, and the CPU 4, it can be eliminated at a low cost without erroneous determination.

The A / D converter for amplifying and outputting the amplifier output of the photocurrent amplifying and outputting the photocurrent emitted from the photosensor is provided by the A / D conversion method.
Although the type in which the / D conversion value indicates the value at the sample time is shown, the present invention can also be applied to a case where the / D conversion value is an average value type displayed by an average value. In other words, the average value type is difficult to accurately capture the rise of spike noise, but as a countermeasure,
Performing every other spike noise determination can prevent erroneous determinations. In other words, when the spike noise at the amplifier output B ′ as shown in FIG. 4H shows the A / D conversion value as an average value within the sample time as shown in FIG. In the time zone indicated by Δ in (I) of FIG. 4, the converted value is increasing, so that it is difficult to judge it as spike noise at first glance. On the other hand, as shown in (J) and (K) in FIG. 4, if every other conversion value is determined from each conversion value in (I) in FIG. 4, it is determined only that the conversion value has increased. Is found to be going from rising to falling, and the spike noise can be determined without error.

[0022]

As described above, according to the present invention,
Or it calculates the A / D conversion value with each other at different times, respectively, with or added to determine the level I _d of the A / D converter in an operation process, by determining whether or start and end of the spike noise, Conventionally, it is difficult to distinguish between the preamplifier output of spike noise and that of the concentration of the component gas to be measured, and there is a risk that spike noise is erroneously determined. Is to use two sets of photosensors and preamplifiers each for the spike noise determination method to avoid the problem of being expensive and to use a simple program to determine the effect of spike noise contained in the amplifier output. Moreover, with a simple configuration including a photo sensor, an amplifier, an A / D converter, and a CPU, no erroneous determination is made and the cost is low. There is a removal can effect.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an entire configuration showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining determination of spike noise in the embodiment.

FIG. 3 is a diagram illustrating processing of a signal component in the embodiment.

FIG. 4 is a diagram illustrating that erroneous determination of spike noise can be avoided by a change in NO gas concentration in the embodiment.

FIG. 5 is an explanatory diagram of the entire configuration showing a conventional example.

FIG. 6 is a diagram showing an output of a conventional example.

FIG. 7 is an explanatory diagram of the entire configuration showing another conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photo sensor, 2 ... Amplifier, 3 ... A / D converter, 4
... Arithmetic processing unit (CPU), J: spike noise determination device, S: NO gas (component gas to be measured), P: ozone gas, B ': amplifier output , A / D conversion value: I (t _n-1 ),
I (t _n ), I (t _{n + 1} ), I (t ′ _n−1 ), I (t ′)
_n ) .

Claims (3)

(57) [Claims] 1. A photosensor for receiving light in proportion to the concentration of a component gas to be measured, which is emitted when a sample gas is introduced together with ozone gas into a reaction cell of a chemiluminescence gas analyzer, and emitted from the photosensor. And an amplifier for amplifying and outputting a photocurrent to be supplied to the A / D converter.
An A / D converter for converting its A / D Ri Do a conversion value from an arithmetic processing unit for calculating and processing to determine the start and end of the spike noise generation, further, the determination of the start time t
_n-1, t _n, at _{t n + 1 (t n-} 1 <t n <t n + 1)
A / D conversion values I (t _n-1 ), I (t _n ), I (t _{n + 1} )
While the end is determined at time t ′ _n−1 ,
A / D conversion at t ' _n (t _{n + 1} <t' _n-1 <t ' _n )
I (t ' _n-1 ), I (t' _n ) and spike noise
It is performed using the A / D conversion value I (t _n-1 ) before birth .
Cormorants configured spike noise determination device and wherein the Ru tare. 2. The component gas to be measured is NO gas, the amplifier is an amplifier having a time constant T of RC (R is a resistor, C is a capacitor), and the A / D converter itself is at each time t _{n. -1} , t _n , and t / _{n + 1} A / D conversion values I (t
_{n-1), I (t} n), spike noise according to claim 1 having a determined level I _d which is determined by the arithmetic processing unit the presence of spike noise from the I (t n + ₁₎ with the desired program Judgment device. 3. A photocurrent emitted from a photosensor which receives light proportional to the concentration of a component gas to be emitted when a sample gas is introduced together with ozone gas into a reaction cell of a chemiluminescence gas analysis unit is amplified. The output of the amplifier is then output, and the result of the A / D conversion is used to start spike noise generation according to the following criteria by the program of the arithmetic processing unit.
A spike noise judging method comprising judging termination.
That is, time t _n−1 , t _n , t _{n + 1} (t _n−1 <t _n <
t _{n + 1} ), the A / D conversion values are
(T _n-1 ), I (t _n ), I (t _{n + 1} ), and the spike noise determination level is I _d , a. _{I (t n) -I (t} n-1) < If I _d, is determined not to be a spike _{noise, I (t n) -I (} t n-1)>
If I _d, below b. Column, b. If I (t _{n + 1} )> I (t _n ), it is determined that the noise is not spike noise. If I (t _{n + 1} ) <I (t _n ), it is determined that the spike noise has started. The end of the noise is determined at times t ′ _n−1 , t ′ _n (t _{n + 1} <
The A / D conversion values at t ' _n-1 <t' _n ) are represented by I
(T ' _n-1 ), I (t' _n ) and the spike noise determination level is I _d , c. _{I (t 'n-1)} <I (t' n), or, I (t '
_n ) A spike noise determination method which includes determining that the case of -I (t _n-1 ) < _Id is satisfied.