JP2012149976A - Measurement apparatus and measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a highly accurate high-speed measurement of the average value of the physical amount of continuously input pulses.SOLUTION: A measurement apparatus includes a process part for executing a measurement process for measuring an average cycle of continuously input pulses (P1 through P4). The process part executes the measurement process including: a time-measurement process of measuring elapsed time Tp from starting time Ts1, which corresponds to the input time of one pulse (P1); a counting process for counting the number of pulses input after the starting time Ts1; and a process of measuring an average value of a physical amount at process target time Ti on the basis of the process target time Ti and the number of pulses counted until the elapsed time Tp reaches specified time Tr, where the process target time Ti is the elapsed time Tp until the input time of a pulse (P) that has been counted at the end during a period until the elapsed time Tp reaches a pre-specified time Tr.

Description

  The present invention relates to a measuring apparatus and a measuring method for measuring a physical quantity of pulses that are continuously input.

  As a measuring device for measuring a physical quantity (for example, frequency) of an input signal and obtaining an average value thereof, for example, a frequency change measuring device disclosed in JP-A-7-55554 is known. This frequency change measuring device includes a counter, a storage circuit, a subtracting circuit, an adding circuit, a dividing circuit, a microprocessor, and the like, measures the frequency of an input signal (resonance frequency), and performs a moving average of n measurement values to obtain a frequency. It is possible to obtain the average value of. In this frequency change measuring apparatus, the counter measures the frequency of the input signal, and the storage circuit stores n measurement values. In this case, when a new measurement value is measured, the storage circuit outputs the oldest measurement value (n previous measurement values) out of the stored n measurement values to the subtraction circuit to generate a new measurement value. Memorize the measured value. The subtracting circuit outputs a difference value obtained by subtracting the n-th previous measured value output from the storage circuit from the new measured value to the adding circuit. Further, the adder circuit adds the accumulated value stored in the memory circuit and the output signal of the subtractor circuit, and stores the sum in the memory circuit again. Further, the division circuit divides the accumulated value stored in the storage circuit by n. As a result, the n measured values are moving averaged to obtain the average value of the frequencies.

Japanese Unexamined Patent Publication No. 7-55554 (page 3, FIG. 1-2)

  However, the above-described frequency change measuring apparatus has the following problems to be solved. That is, in this frequency change measuring apparatus, every time the frequency is measured by the counter, the measured value is transferred between the memory circuit, the subtracting circuit, the adding circuit, and the dividing circuit. When the number n of measured values is set to be large, the number of times the measured values are transferred between the circuits increases, and accordingly, high-speed processing becomes difficult. On the other hand, the following method is known as a method of performing an average value of measured values at high speed. In this method, for example, when calculating the average value of the frequency of continuously input pulses as the physical quantity of the input signal, the number of pulses input within a predetermined specified time is counted, and the specified time is calculated. The reciprocal of the value divided by the number of counts is taken as the average value of the frequency over the specified time. However, in this method, a time interval of about one cycle of the pulse occurs at the maximum from the input time of the last input pulse within the specified time to the end time of the specified time. There is a risk that the average value of the frequencies calculated in this way will be inaccurate.

  The present invention has been made to solve such a problem, and a main object of the present invention is to provide a measuring apparatus and a measuring method capable of accurately and rapidly measuring an average value of physical quantities of continuously input pulses. .

  In order to achieve the above object, the measurement apparatus according to claim 1 is a measurement apparatus including a processing unit that executes a measurement process for measuring a physical quantity of pulses that are continuously input. A time counting process for measuring an elapsed time from the start time with the input time of the pulse as a start time; a count process for counting the number of pulses input after the start time; and the elapsed time Counting the number of pulses counted until the elapsed time reaches the specified time, with the elapsed time until the input time of the pulse counted last as the processing target time until the predetermined time is reached And a process of measuring an average value of the physical quantities at the process target time based on the process target time as the measurement process.

  The measuring device according to claim 2 is provided with an operation unit capable of performing an operation of setting the specified time to an arbitrary value in the measuring device according to claim 1, and the processing unit is configured by an operation on the operation unit. The measurement process is executed based on the set specified time.

  The measurement method according to claim 3 is a measurement method for executing a measurement process for measuring a physical quantity of pulses that are continuously input. The measurement is performed from an input time point of one pulse as a start time point. A time measuring process for measuring the elapsed time and a counting process for counting the number of the pulses input after the start time are executed, and finally, until the elapsed time reaches a predetermined specified time. Based on the count number of the pulses counted until the elapsed time reaches the specified time and the processing target time, the elapsed time until the counted pulse input time is the processing target time. A process for measuring the average value of the physical quantities is executed as the measurement process.

  According to the measuring apparatus according to claim 1 and the measuring method according to claim 3, a time measuring process for measuring an elapsed time from an input time point of one pulse as a start time point, and a pulse input after the start time point By executing the counting process that counts the number, the processing target time that is the elapsed time up to the input point of the last counted pulse and the elapsed time reach the specified time until the elapsed time reaches the specified time It is possible to accurately specify the count number of pulses counted up to now. Therefore, according to this measurement apparatus and measurement method, as a physical quantity for a pulse, based on the processing target time and the count number (for example, by calculating the reciprocal of the average period obtained by dividing the processing target time by the count number) It is possible to accurately measure the average value of the frequencies. Further, according to this measuring apparatus and measuring method, it is not necessary to measure the frequency each time a pulse is newly input and store the data in the storage unit, and when the elapsed time reaches the specified time, the processing target time Since the average value of the frequencies can be measured by performing the calculation based on the count number, the measurement can be performed at high speed.

  According to the measurement device of claim 2, by performing the measurement process based on the specified time set to an arbitrary value by an operation on the operation unit, for example, a graph showing a change in the average value of the frequency is displayed on the display unit Since the specified time can be set according to the length of the time axis that can be displayed in the display area of the display unit, the graph can be displayed in an easy-to-view manner.

1 is a configuration diagram of a measuring device 1. FIG. 4 is a waveform diagram of an AC voltage signal Sv and a pulse P. FIG. 5 is a flowchart of a frequency measurement process 50. It is the 1st explanatory view explaining a measuring method. It is the 2nd explanatory view explaining a measuring method. It is the 3rd explanatory view explaining a measuring method.

  Hereinafter, embodiments of a measurement apparatus and a measurement method will be described with reference to the accompanying drawings.

  First, the configuration of the measuring apparatus 1 will be described with reference to the drawings. A measuring apparatus 1 shown in FIG. 1 is an example of a measuring apparatus, and includes a pulse output unit 11, a processing unit 12, an operation unit 13, a storage unit 14, and a display unit 15.

  The pulse output unit 11 performs a pulse output process according to the control of the processing unit 12. In this case, as shown in FIG. 2, the pulse output unit 11 receives an analog signal (an AC voltage signal Sv as an example) in the pulse output process, and the voltage value V of the AC voltage signal Sv is compared with the comparison value Vr ( As an example, when the voltage exceeds 0 V), a pulse P having a predetermined time length is output.

  The processing unit 12 controls each unit in accordance with the operation signal output from the operation unit 13. Further, the processing unit 12 inputs the pulses P continuously output by the pulse output unit 11 by executing the frequency measurement processing 50 (an example of the measurement processing) shown in FIG. The average value (average period Tc and average frequency fa) of physical quantities (as an example, the period and frequency of each pulse P) is measured. In this case, the processing unit 12 includes an internal timer (not shown). In the frequency measurement process 50, the time measurement process and the integration process to be described later are performed using the time data output from the internal timer, and will be described later. Execute count processing.

  The operation unit 13 includes a power switch, various operation keys, and the like, and outputs an operation signal when these are operated. In addition, the operation unit 13 is configured to be capable of performing an operation of setting a prescribed time Tr used in the frequency measurement process 50 executed by the processing unit 12 to an arbitrary value. The storage unit 14 stores a specified time Tr input by an operation on the operation unit 13. The storage unit 14 also stores the average frequency fa of the pulse P measured by the processing unit 12. The display unit 15 displays a graph showing a change in the average frequency fa according to the control of the processing unit 12.

  Next, a measurement method for measuring the frequency (an example of a physical quantity of a pulse) of pulses P that are continuously input using the measurement apparatus 1 and the operation of the measurement apparatus 1 at that time will be described with reference to the drawings.

  Prior to the measurement, a specified time Tr used in the frequency measurement process 50 executed by the processing unit 12 is input. In this case, as an example, it is assumed that the specified time Tr is set to 0.85 seconds (850 ms) (see FIG. 4). At this time, the processing unit 12 stores the specified time Tr in the storage unit 14 in accordance with the operation signal output from the operation unit 13.

  Next, the operation unit 13 is operated to instruct the start of measurement. At this time, the processing unit 12 causes the pulse output unit 11 to start pulse output processing according to the operation signal. In this pulse output process, as shown in FIG. 2, the pulse output unit 11 receives an AC voltage signal Sv (analog signal), and the voltage value V of the AC voltage signal Sv becomes a comparison value Vr (0 V as an example). When it exceeds, pulse P is output.

  Subsequently, the processing unit 12 executes a frequency measurement process 50 shown in FIG. In the frequency measurement process 50, the processing unit 12 reads the specified time Tr from the storage unit 14 (step 51). Next, the processing unit 12 executes a reset process for resetting an elapsed time Tp, a processing target time Ti, and a count number N, which will be described later (step 52).

  Subsequently, the processing unit 12 determines whether or not the first pulse P from the pulse output unit 11 after execution of the reset process has been input (step 53). In this case, when the processing unit 12 determines that the first pulse P (corresponding to one pulse, for example, the pulse P0 shown in FIG. 4) is input, the processing unit 12 starts a time counting process, a count process, and an integration process (Step S1). 54).

  The processing unit 12 measures the elapsed time Tp from the start time Ts1 using the time data output from the internal timer, with the input time of the pulse P0 as the start time Ts1 (see FIG. 4) in the above-described time measurement process. To do. Further, the processing unit 12 determines whether or not a new pulse P is input after the start time Ts1 in the time measurement process (step 55). In this case, when determining that the new pulse P is not input, the processing unit 12 determines whether or not the elapsed time Tp has reached the specified time Tr (step 56), and the new pulse P is input. Is determined, the count number N, which will be described later, is incremented (step 57) and the cycle is integrated (step 58), and then step 56 is executed.

  Further, when the processing unit 12 determines that the elapsed time Tp has not reached the specified time Tr in Step 56 described above, the processing unit 12 executes Step 55. That is, the processing unit 12 repeatedly executes Steps 55 and 56 (or 55, 57, 58, and 56) until it is determined that the elapsed time Tp has reached the specified time Tr.

  Further, the processing unit 12 counts the number of input pulses P in the above-described counting process. Specifically, when determining that a new pulse P (for example, pulse P1 shown in FIG. 4) is input in step 55 described above, the processing unit 12 increments the count number N by “1”. (Step 57). In this case, as described above, the processing unit 12 repeatedly executes steps 55 and 56 (or 55, 57, 58, and 56) until it is determined that the elapsed time Tp has reached the specified time Tr. Accordingly, the processing unit 12 increments the count number N by “1” every time a new pulse P is input until it is determined that the elapsed time Tp has reached the specified time Tr in this counting process. To count the number of pulses P input within the specified time Tr.

  Further, the processing unit 12 integrates the period of the input pulse P in the above-described integration process. Specifically, when the processing unit 12 determines that a new pulse P (for example, the pulse P1 shown in FIG. 4) is input in step 55 described above, the processing unit 12 inputs the pulse P0 input immediately before the pulse P1. The period from the time point to the input time point of the newly input pulse P1 is specified using the time data output from the internal timer, and the specified period is integrated (step 58). In this case, as described above, the processing unit 12 repeatedly executes steps 55 and 56 (or 55, 57, 58, and 56) until it is determined that the elapsed time Tp has reached the specified time Tr. Therefore, the processing unit 12 integrates the period of the pulse P every time a new pulse P is input until it is determined that the elapsed time Tp has reached the specified time Tr in this integration process, and thereby the specified time is reached. The period of all the pulses P input in Tr is integrated.

  Next, when it is determined in step 56 that the elapsed time Tp has reached the specified time Tr, the processing unit 12 stops the time measurement process, the count process, and the integration process (step 59), and then continues at that time. The elapsed time Tp (see the figure) until the input time of the last pulse P (for example, the pulse P3 shown in FIG. 4) counted until the accumulated time of the cycle (that is, the elapsed time Tp) reaches the specified time Tr. The processing target time Ti is set (step 60). Next, the processing unit 12 measures an average value of the frequency of the pulse P in the processing target time Ti (hereinafter, this average value is also referred to as “average frequency fa”) (step 61). Specifically, the processing unit 12 first divides the processing target time Ti by the count number N to thereby obtain an average value of periods in the processing target time Ti (hereinafter, this average value is also referred to as “average period Tc”). Is measured (calculated) (Tc = Ti / N). Subsequently, the processing unit 12 measures (calculates) the reciprocal of the average period Tc as the average frequency fa (fa = 1 / Tc).

  In this case, as an example, as shown in FIG. 4, three pulses P1 to P3 are input after the start time Ts1 until the specified time Tr elapses after the start time Ts1 (the count number N is 3). ) When the elapsed time Tp from the start time Ts1 to the input time of the pulse P3 is 750 ms, the processing unit 12 sets the processing target time Ti to 750 ms, and the processing unit 12 250 ms obtained by dividing 750 ms by 3. Is measured as an average period Tc. Further, the processing unit 12 measures 4 Hz that is the reciprocal of 250 ms as the average frequency fa.

  Next, the processing unit 12 stores the measured average frequency fa in the storage unit 14. Subsequently, the processing unit 12 executes a reset process to reset the elapsed time Tp, the processing target time Ti, and the count number N (step 62). Thus, the first measurement of the average frequency fa is completed.

  Here, in the conventional configuration and method in which the inverse of the value obtained by dividing the specified time Tr by the count number N is measured as the average frequency fa, the average frequency fa may be inaccurate. Specifically, as shown in FIGS. 5 and 6, for example, when the prescribed time Tr is set to 850 ms and three pulses P1 to P3 are input during the time from the start time Ts1 until the prescribed time Tr elapses ( A value obtained by dividing the specified time Tr by the count number N (hereinafter, this value is also referred to as “time Td”) when the count number N is 3 is approximately 283 ms.

  On the other hand, in this case, for example, as shown in FIG. 5, when the elapsed time Tp from the start time Ts1 to the input time of the pulse P3 is 810 ms, the average period Tc of the pulses P1 to P3 is 270 ms. That is, since the time Td (283 ms) obtained by dividing the specified time Tr by the count N is different from the average period Tc, the average frequency fa measured as the reciprocal of the time Td and the original average frequency fa that is the reciprocal of the average period Tc Have different values. As shown in FIG. 6, when the elapsed time Tp from the start time Ts1 to the input time of the pulse P3 is 650 ms, the average period Tc of the pulses P1 to P3 is about 216 ms, and the difference from the time Td is further increased. Therefore, the average frequency fa measured as the reciprocal of the time Td and the original average frequency fa are different from each other.

  On the other hand, in the measurement apparatus 1 and the measurement method, the processing target time Ti and the count number N can be accurately specified by executing the above-described time measurement process, count process, and integration process. Based on the time Ti and the count number N (by calculating the reciprocal of the value obtained by dividing the processing target time Ti by the count number N), the average frequency fa that is the reciprocal of the average period Tc can be accurately measured. ing.

  Further, in this measuring apparatus 1 and measuring method, unlike the conventional configuration and method in which the average value of the frequency is measured by the processing by the moving average method, the frequency is measured each time a pulse P is newly input and the data is obtained. The average frequency fa can be measured by performing calculation based on the processing target time Ti and the count number N when it is determined that the elapsed time Tp has reached the specified time Tr without being stored in the storage unit 14. For this reason, in this measuring apparatus 1 and the measuring method, it is possible to perform measurement at high speed.

  Next, the processing unit 12 performs the above-described steps 54 to 62 to measure the average frequency fa for the second time. In this case, the processing unit 12 sets the input time point of the last input pulse P (pulse P3 in the example of FIG. 4) within the specified time Tr in the first measurement of the average frequency fa as a new start time point Ts2 (same figure). The time counting process is executed by setting as a reference), and the counting process and the integrating process are executed with the pulse P input after the pulse P3 as a new pulse P.

  Thereafter, the processing unit 12 repeatedly performs steps 54 to 61 to repeatedly measure the average frequency fa. Further, the processing unit 12 causes the display unit 15 to display a graph indicating the change in the measured average frequency fa.

  As described above, according to the measurement apparatus 1 and the measurement method, the time counting process for measuring the elapsed time Tp from the start time points Ts1 and Ts2, and the count for counting the number of pulses P input after the start time points Ts1 and Ts2. By executing the processing, the processing target time Ti, which is the elapsed time Tp until the input time point of the last pulse P counted until the elapsed time Tp reaches the specified time Tr, and the elapsed time Tp are the specified time Tr. It is possible to accurately specify the count number N of the pulses P counted until reaching. Therefore, according to the measurement apparatus 1 and the measurement method, based on the processing target time Ti and the count number N (for example, by calculating the reciprocal number of the average period Tc obtained by dividing the processing target time Ti by the count number N). ) It is possible to accurately measure the average frequency fa, which is an average value of frequencies as physical quantities of the pulse P. Further, according to the measuring apparatus 1 and the measuring method, it is not necessary to measure the frequency each time the pulse P is newly input and store the data in the storage unit 14, and the elapsed time Tp reaches the specified time Tr. Since the average frequency fa can be measured by performing calculation based on the processing target time Ti and the count number N, the measurement can be performed at high speed.

  In addition, according to the measurement apparatus 1 and the measurement method, by executing the frequency measurement process 50 based on the specified time Tr set to an arbitrary value by the operation on the operation unit 13, for example, a change in the average frequency fa is performed. When the graph to be displayed is displayed on the display unit 15, the specified time Tr can be set according to the length of the time axis that can be displayed in the display area of the display unit 15, so that the graph can be displayed easily. .

  Note that the measurement apparatus and the measurement method are not limited to the above configuration and method. For example, an average value (average period Tc) as a physical quantity for the pulse P is measured (calculated), and an average value (average frequency fa) as a physical quantity for the pulse P is measured (calculated) from the average period Tc. ), The configuration and method of measuring the average value of the duty ratio as another example of the physical quantity of the pulse P can also be adopted. In the above configuration and method, the average period Tc is measured and the reciprocal number of the average period Tc is measured as the average frequency fa. However, the average frequency fa is measured by dividing the count number N by the processing target time Ti. Also good.

DESCRIPTION OF SYMBOLS 1 Measuring apparatus 12 Processing part 13 Operation part fa Average frequency N Count number P Pulse Tc Average period Ti Process target time Tp Elapsed time Tr Specified time Ts1 Start time Ts2 Start time

Claims (3)

A measurement apparatus including a processing unit that executes a measurement process for measuring a physical quantity of pulses that are continuously input,
The processing unit performs a time measurement process that measures an elapsed time from the start time point with an input time point of one pulse as a start time point, and a count process that counts the number of pulses input after the start time point In addition, the elapsed time until the last pulse input time counted until the elapsed time reaches a predetermined specified time is set as the processing target time until the elapsed time reaches the specified time. A measurement apparatus that executes, as the measurement process, a process of measuring an average value of the physical quantities in the processing target time based on the counted number of pulses counted and the processing target time. An operation unit capable of setting the prescribed time to an arbitrary value;
The measurement apparatus according to claim 1, wherein the processing unit performs the measurement process based on a specified time set by an operation on the operation unit. A measurement method for executing a measurement process for measuring a physical quantity of pulses that are continuously input,
A time counting process for measuring an elapsed time from the start time point with an input time point of one of the pulses as a start time point and a count process for counting the number of pulses input after the start time point are performed. The elapsed time until the input time point of the pulse counted last until the time reaches a predetermined specified time is set as the processing target time, and the pulse counted before the elapsed time reaches the specified time. A measurement method for executing, as the measurement process, a process of measuring an average value of the physical quantities in the process target time based on a count number and the process target time.

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