KR101203041B1 - Method of measuring an amplitude of a sinusoidal wave using a phase difference and apparatus thereof - Google Patents

Abstract

PURPOSE: A sine wave amplitude measuring method using a phase difference and a device thereof are provided to optimize multi-channel measurement composition for accurate measurement of sine wave amplitude outputted in a plurality of parts of an object at the same time. CONSTITUTION: A signal sensing unit(120) receives a sine wave signal applied from an external. A reference signal generating unit generates a reference signal. The reference signal is outputted as a sine wave having a phase difference between the sine wave signal and a known quantity and having the same period of the sine wave signal and the known quantity. The reference signal is generated as the sine wave. A first comparing unit(140) generates a synchronized reference square wave according to comparison between the reference signal and a reference level. A second comparing unit(150) generates a synchronized comparison square wave according to the comparison between the reference signal and the sine wave signal. A reference detecting unit(160) detects reference edge time corresponding to a case that the reference signal and the reference level are identical in the reference square wave. A cross detecting unit(170) detects a first cross time corresponding to the case that the sine wave signal and the reference signal are identical in the comparison square wave. An amplitude calculating unit(180) calculates an amplitude of the sine wave signal based on a period and the phase difference of the known quantity and the first cross time. [Reference numerals] (120) Signal sensing unit; (130) Phase lag unit; (160) Reference detecting unit; (170) Cross detecting unit; (180) Amplitude calculating unit

Description

Method of measuring sinusoidal amplitude using phase difference and its device {Method of measuring an amplitude of a sinusoidal wave using a phase difference and apparatus}

The present invention relates to a sinusoidal amplitude measurement method and apparatus, and more particularly to a sinusoidal amplitude measurement method and apparatus using a phase difference between the output sinusoidal signal and the reference signal.

In order to grasp the characteristics or the physical properties of the object, electrical, mechanical, and chemical methods may be used, and as an electrical method, a method of analyzing a characteristic from an amount of change of the signal by applying an electrical signal to the object may be applied. Such objects may be biological tissues, machines, civil structures, and the like.

On the other hand, as a measurement method of a biological signal in a living tissue, a method of externally detecting a signal generated from a signal source in a living body (electrocardiogram, electrocardiogram, electromyography, etc.) and an electrical signal that does not exist in the living body are applied to the biological physiological phenomenon. And a method of measuring a modified signal by being modulated by deformation or change of tissue. In the former case, the signal is small (about 1 mV or less), and there are so many signal sources in vivo that it is very difficult to separate them. Therefore, the latter method, that is, the method described above can be used to increase the strength of the electrical signal and to remove noise from the signal source in vivo.

In addition, in the case of mechanical or civil engineering structures, vibration measurement or displacement measurement may be performed from the amount of change in the electrical signal applied thereto. The method may also be applied to a displacement variable magnetic sensor (LVDT) for measuring dimension changes due to expansion and contraction of a sample.

The above-listed methods can apply a sinusoidal wave of a specific frequency and detect and use the modified signal thereof. Accordingly, the characteristics of the object can be understood by measuring the change in the amplitude of the sinusoidal wave passing through the object.

The measurement of sinusoidal amplitude change is mainly using a phase-sensitive demodulation technique, and the measurement of sinusoidal amplitude change is mainly using a conventional phase sensitive demodulation method. ADC (Analog to Digital Converter) is used. However, all of the ADCs of the Successive Approximation Register or the ADCs of the Sigma Delta method are sensitive to temperature change, and in particular, have limitations in minimizing DNL (Differential Nonlinearity) errors, which is a limitation of the phase sensitive demodulation method. Accordingly, such a phase sensitive demodulation method has a low accuracy in measuring sinusoidal amplitude.

In addition, in the case of the measurement of each sinusoidal amplitude simultaneously outputted from a plurality of parts of an object, that is, a multichannel measurement configuration, the phase sensitive demodulation method requires more computation, which is extremely unsuitable for multichannel measurement. Moreover, the phase sensitive demodulation method requires trigonometric multiplication and trigonometric integration, which requires a large amount of computation when implementing a system of hundreds of channels or more. In addition, when implementing a system of more than a few hundred channels, there is a problem of deviation between ADCs.

Therefore, there is a continuous study on the method and apparatus for measuring sinusoidal amplitude, which is sensitive to temperature and is more suitable for a multichannel measurement configuration. Moreover, as the concept and development of the ubiquitous healthcare system has recently spread, attempts to monitor and analyze various biological signals in daily life are increasing. Acquiring a multi-channel bio signal is required, and there is a demand for the implementation of a measurement method that can be measured during prolonged movement.

The technical problem to be solved by the present invention is sine wave amplitude measurement, which is robust to temperature sensitivity, improves the accuracy of amplitude measurement, and is optimized for a multi-channel measurement configuration for the measurement of each sinusoidal amplitude simultaneously outputted in a plurality of parts of an object. A method and apparatus are provided.

More specifically, the present invention is simpler in structure than the conventional analog-to-digital conversion method, and the calculation amount is significantly reduced, which is suitable for implementing a multichannel, low power, and small biosignal measurement system.

The object of the present invention is not limited to the above-mentioned object, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention for achieving the above technical problem, the method for measuring sinusoidal amplitude using a phase difference has a step of receiving a sinusoidal signal applied from the outside, and having the same period known to the sinusoidal signal, Generating a reference signal output as a sinusoidal wave having a known phase difference from the sinusoidal signal, generating a reference square wave synchronized with the comparison between the reference signal and a reference level, and the sinusoidal signal and the Generating a comparison square wave in synchronization with the comparison between the reference signals; Detecting, at the reference square wave, a reference edge time corresponding to the case where the reference signal and the reference level are the same; and after the reference edge time, the sinusoidal signal and the reference signal are the same in the comparison square wave. Detecting a first cross time corresponding to a case and calculating an amplitude of the sinusoidal signal based on the period, the known phase difference, and the first cross time.

According to another aspect of the present invention for achieving the above technical problem, the sinusoidal wave amplitude measuring apparatus has a signal detection unit for receiving a sinusoidal signal applied from the outside, the sinusoidal signal and the same period known to the sinusoidal signal, A reference signal generator for generating a reference signal output as a sine wave having a known phase difference from the sine wave signal, a first comparator for generating a reference square wave synchronized with the comparison between the reference signal and a reference level, and the sine wave signal A second comparator for generating a comparison square wave synchronized according to the comparison between the reference signals, a reference detector for detecting a reference edge time corresponding to the case where the reference signal and the reference level are the same in the reference square wave; After the reference edge time, the sinusoidal signal and the reference signal are the same in the comparison square wave. If, based on the cross detection section for detecting a first cross-hour period, and the phase difference and the time the first cross of the base that corresponds to, and includes an amplitude calculation for calculating the amplitude of the sinusoidal signal.

Specific details of other embodiments are included in the detailed description and the drawings.

According to the present invention, the structure is simpler than the conventional analog-to-digital conversion method, and the calculation amount is significantly reduced, which is suitable for implementing a multichannel, low power, and small biosignal measurement system. Accordingly, by the present invention, the accuracy of the amplitude measurement is significantly improved due to the robustness of temperature sensitivity, and can be optimized for the multi-channel measurement configuration for the accurate measurement of each sinusoidal amplitude output at the same time in multiple parts of the object.

In addition, when the sinusoidal signal is output based on an excitation signal having the same frequency and phase, and the reference signal is output to have a different phase from the excitation signal based on the same excitation signal, the reference signal and the sinusoidal signal are identical. Since the signal is shared, noise immunity may have a strong noise characteristic.

1 is a block diagram of a sine wave amplitude measuring apparatus according to an embodiment of the present invention.
2 is a block diagram of a sine wave amplitude measuring apparatus according to another embodiment of the present invention. 3 and 4 are diagrams for explaining a sine wave amplitude measuring method according to an embodiment of the present invention.
5 is a diagram for describing a sine wave amplitude measuring method according to another exemplary embodiment of the present invention.
6 is a block diagram of a sine wave amplitude measuring apparatus according to still another embodiment of the present invention.
7 is a diagram for describing a sine wave amplitude measuring method according to still another embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described below. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments disclosed herein are being provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Like numbers refer to like elements throughout. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular forms also include the plural unless specifically stated otherwise in the text. &Quot; comprises "and / or" comprising ", as used herein, unless the recited element, step, operation, and / Or additions.

Hereinafter, a sinusoidal amplitude measuring apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 1, 3, and 4. 1 is a block diagram of a sine wave amplitude measuring apparatus according to an embodiment of the present invention, Figures 3 and 4 are diagrams for explaining a sine wave amplitude measuring method according to an embodiment of the present invention.

The sinusoidal amplitude measuring apparatus 100 is a device for receiving a sinusoidal signal applied from the outside and measuring the amplitude thereof. The sine wave signal applied from the outside may be a signal output from a sensor for sensing a characteristic of the object, and the object may be a biological tissue, a machine, a solid sample, a civil structure, or the like. When the object is a biological tissue, by using the sinusoidal amplitude measurement apparatus 100 including a sensor, the presence or absence of various cancers as a specific symptom in the biological tissue that can be regarded as a kind of resistive device may be determined. The sinusoidal amplitude measuring apparatus 100 may be applied to a linear variable differential transformer (LVDT) for measuring a change in size due to expansion and contraction of a sample.

In this embodiment, the excitation signal of the excitation power supply 110 is input to the signal detection unit 120, is applied to the object electrically connected to the signal detection unit 120, and then the signal detection unit transmits a signal passing through the object. The output through the 120 and measuring the amplitude of the output signal will be described as an example. That is, the signal detecting unit 120 in the present embodiment described below will be mainly described as functioning as a sensor. However, the present embodiment is not limited to the above-mentioned matters, and the equivalent technical idea derived from the claims. It can be extended and applied, for example, to amplitude measurements of sinusoidal signals received from the outside by various forms other than sensor outputs.

The sinusoidal amplitude measuring device 100 includes an excitation power supply 110 for generating an excitation signal of a sinusoidal wave, a signal detector 120 for applying an excitation signal to an object, and providing a sinusoidal signal output therefrom, and an excitation power supply 110. And a reference signal generator which is electrically connected to the second signal to generate a reference signal transitioned to another known phase.

The excitation power supply 110 may generate a sinusoidal excitation signal having a predetermined angular frequency (ω) and a phase, for example, sinωt (Vpp = 1), and apply the generated signal to the signal detector 120 and the phase delay unit 130. . The excitation signal is described as a sinusoidal voltage signal having a phase of 0 degrees for convenience of description, but may be a sinusoidal voltage signal having a different phase or a sinusoidal current signal having a predetermined phase.

The signal detector 120 may receive an excitation signal, apply the excitation signal to an object, and employ a sinusoidal wave signal (see 10 in FIGS. 3 and 4) output therefrom as an output signal. If the object is a biological tissue, the signal detector 120 may function as a biological signal sensor, and when a low frequency excitation sinusoidal signal is applied to the biological tissue, the biological tissue may ignore inductive and capacitive components. It may be regarded as having a small amount as small as possible, and may be regarded as having substantially no resistance, and generally has a resistive component. The output sinusoidal signal 10 may have an amplitude substantially equal to or smaller than the excitation signal, It may be output to have an angular frequency (ω) and a phase equal to. That is, since the output sinusoidal signal 10 has the same period and phase as the excitation signal, when the excitation signal is sinωt (Vpp = 1), the output sinusoidal signal 10 may be Xsinωt (0 <X≤1). have.

The reference signal generator is connected to the excitation power supply 110 to generate a reference signal (see 12 in FIGS. 3 and 4) that is shifted to a known phase different from the excitation signal. For example, the reference signal generator may use the phase delay unit 130 as shown in FIG. 1. If the excitation signal is sinωt (Vpp = 1), the reference signal 12 may be sin (ωt−φ) to have a delayed known phase difference (φ> 0, eg 45 degrees) with the excitation signal. Of course, the above-described reference signal generator may generate a reference signal having a known phase difference earlier than the excitation signal. In another embodiment, the phase delay unit 130 may be connected to an output terminal of the signal detector 120 to generate a reference signal having a delayed phase from the output sinusoidal signal. The reference signal 12 is a signal generated to serve as a reference signal for detecting the cross time.

In addition, the sinusoidal amplitude measuring apparatus 100 generates a reference square wave (see 14 of FIGS. 3 and 4) that is synchronized according to a comparison between the reference signal 12 output from the phase delay unit 130 and the reference level. A second generating square wave (see 16 in FIG. 4) that is synchronized according to the comparison between the generated sinusoidal signal 10 from the first comparator 140 and the signal detector 120 and the reference signal 12. Comparing unit 150 is included.

In detail, the first comparator 140 receives the reference signal 12 and a zero level that is a reference level, for example, a ground voltage, and has a constant first positive value when the reference signal 12 is greater than the zero level. Reference square wave 14 with a constant first negative value may be generated when signal 12 is less than zero level. The absolute value of the first positive value and the first negative value of the reference square wave may be output to have Vpp = 1. In addition, the first comparator 140 may be designed with a known circuit configuration.

The second comparator 150 receives the output sinusoidal wave signal 10 and the reference signal 12, has a constant second positive value when the output sinusoidal wave signal 10 is larger than the reference signal 12, and output sinusoidal wave signal. When (10) is smaller than the reference signal 12, it is possible to generate a comparison square wave 16 having a constant second negative value. The absolute value of the second positive value and the second negative value of the comparison square wave may be output to have Vpp = 1. In addition, the second comparator 150 may be designed in a known circuit configuration.

As such, the reason for changing the sine wave to the square wave 14 or 16 through the first and second comparators 140 and 150 is to use the time precision of the high speed digital microprocessor. For example, the digital signal time resolution of a 1 GHz clock rate microprocessor or field programmable gate array (FPGA) is 1/1 GHz = 1 nsec. Since the phase difference is a time difference, the sinusoidal wave is converted into a square wave to take advantage of a digital device having high time resolution.

In addition, the sinusoidal amplitude measuring apparatus 100 detects a reference edge time (see t _{r in} FIG. 4) corresponding to the case where the reference signal 12 and the zero level are the same in the reference square wave 14. 160, after the reference edge time t _r , a first cross time corresponding to the case where the output sinusoidal signal 10 and the reference signal 12 are the same in the comparison square wave 16 (see t _{c in} FIG. 4). From the signal detection unit 120 on the basis of the cross detection unit 170 for detecting a signal and the angular frequency ω of the excitation signal, the known phase φ of the reference signal 12 and the first cross time t _c . And an amplitude calculator 180 that calculates an amplitude of the output sinusoidal signal 10.

Specifically, the reference detector 160 may detect that the reference signal 12 is at a zero level by detecting a predetermined reference falling edge at the reference square wave 14, and may refer to the reference square wave 14. The reference edge time t _r , which is a time corresponding to the falling edge, may be calculated.

Further, the cross detecting section 170 detects the comparison falling edge of the reference edge time (t _r) with reference to, the time (t _r) comparing the square wave 16 is present in the predetermined period of the reference square wave 14 after the As a result, the output sinusoidal signal 10 and the reference signal 12 may be estimated to be the same as Vc, and the first square time t _c corresponding to the comparison falling edge may be calculated in the comparison square wave 16. When the reference detector 160 detects a reference rising edge from the reference square wave 14, the cross detector 170 refers to a time corresponding to the reference rising edge, and thus a predetermined period of the reference square wave 14. The first cross time t _c can be calculated by detecting the comparative rising edge of the comparison square wave 16 within.

The amplitude calculator 180 is output from the signal detector 120 based on the angular frequency ω of the excitation signal, the known phase φ of the reference signal 12 and the first cross time t _c . X, which is the amplitude of the sinusoidal signal 10, may be calculated, and a detailed algorithm thereof will be described later. Meanwhile, the reference detector 160, the cross detector 170, and the amplitude calculator 180 described in this embodiment may be implemented in software by a microprocessor or an FPGA.

The sinusoidal amplitude measuring device according to the present invention is designed to simplify the circuit structure, compared to the conventional phase-sensitive demodulation amplitude measuring device, and thus is robust to the temperature sensitivity caused in implementation. For this reason, accurate measurements can be made while optimizing multi-channel measurements for the measurement of each sinusoidal amplitude simultaneously output from multiple parts of the object. That is, the amplitude measuring device of the present invention has a simpler structure than the conventional analog-to-digital conversion method and significantly reduces the amount of calculation, and is suitable for implementing a multichannel, low power, and small biosignal measuring system.

In addition, since the output sinusoidal signal 10 and the reference signal 12 are output based on the excitation signal of the common excitation power supply 110, even if there is noise in the excitation signal, the output sinusoidal signal 10, or the like, the immunity to such noise is strong. Can have characteristics.

On the other hand, with reference to Figure 2, a sinusoidal wave amplitude measuring apparatus according to another embodiment of the present invention will be described. 2 is a block diagram of a sine wave amplitude measuring apparatus according to another embodiment of the present invention.

Another embodiment of the present invention includes a configuration substantially the same as the embodiment shown in FIG. 1, except for the configuration of generating the reference signal, and mainly describes a configuration different from the embodiment of FIG. Specifically, the excitation power source 210, the signal detector 220, the first and second comparators 240 and 250, the reference detector 260, the cross detector 270, and the amplitude calculator 280 are illustrated in FIG. 1. The excitation power source 110, the signal detector 120, the first and second comparators 140 and 150, the reference detector 160, the cross detector 170, and the amplitude calculator 180 described through FIG. Plays the same function. Another embodiment does not include the phase delay unit 130, which is the reference signal generator mentioned in the embodiment of FIG. 1, but instead the reference signal 22 outputs from the reference power source 230 independent of the excitation power source 210. The signal may be output to have the same angular frequency? As the power signal of the excitation power supply 210 and to have a known phase difference φ different from the excitation signal. In this case, the reference signal 22 may be generated to have a delayed phase than the excitation signal, for example, a delay phase of 45 degrees.

Hereinafter, referring to FIGS. 1, 3, and 4 again, a sine wave amplitude measuring method according to an exemplary embodiment of the present invention will be described using the sine wave amplitude measuring apparatus 100 shown in FIG. 1. An embodiment to be described later will be described mainly with respect to the sinusoidal amplitude measuring apparatus 100 of FIG. 1, but of course, the sinusoidal amplitude measuring apparatus 200 of FIG. 2 may also be applied by generating a reference signal independently of the excitation signal. For convenience of description, the signal detector 120 is a sensor described through the embodiment of FIG. 1, and an object detected by the sensor may be a living tissue having a resistive component, and the like, and an excitation signal and a signal detection of the excitation power supply 110. The output sinusoidal signal 10 of the unit 120 is a sinusoidal voltage signal and will be described with an example of sin ω t (Vpp = 1) and X sin ω t (0 <X ≦ 1).

The sine wave signal 10 applied by the excitation signal to an object, for example, a living tissue, is output from the signal detection unit 120, and the phase delay unit 130 is the same angular frequency ω as the excitation signal, but the excitation signal And a reference signal 12 with sin (ωt−φ) (Vpp = 1) having a known phase difference φ and.

Subsequently, the first comparator 140 receives the reference signal 12 and the zero level, which is a reference level, generates a reference square wave 14 that is synchronized according to a comparison therebetween, as shown in FIG. The comparator 150 may receive the output sinusoidal wave signal 10 and the reference signal 12 and generate a comparison square wave 16 according to a comparison therebetween, as shown in FIG. 4. In this case, the square waves 14 and 16 of the first and second comparators 140 and 150 may be output to have the same absolute value (Vpp = 1).

Next, the reference detection unit 160 receives the reference square wave 14 and detects a predetermined reference falling edge therefrom, whereby the reference signal 12 is estimated to have a zero level in the reference square wave 14. As a result, as shown in FIG. 3, the reference edge time t _r , which is a time corresponding to the reference falling edge, may be calculated. Subsequently, the cross detector 170 detects the comparison falling edge of the comparison square wave 16 existing within one period (see the arrow in FIG. 4) of the reference square wave 14 after the reference edge time t _r . The output sinusoidal signal 12 and the reference signal 12 are assumed to be equal to Vc, whereby the first cross time t _c corresponding to the comparison falling edge in the comparison square wave 16, as shown in FIG. Can be calculated.

Next, the amplitude calculating unit 180 based on the angular frequency ω of the excitation signal, the known phase φ of the reference signal 12 and the first cross time t _c , the signal detecting unit 120. X, which is the amplitude of the sinusoidal signal 10 outputted from the equation, can be calculated by the following expression (1). The amplitude X can be calculated from this because the angular frequency ω, the phase φ and the first cross time t _c are already known.

sin (ωt _c -φ) = Xsinωt _c = Vc (1)

Since the sine wave amplitude measuring method according to the present invention can be designed to be robust to the temperature sensitivity caused in a circuit implementing the simplification algorithm, compared to the amplitude measuring method by the conventional phase sensitive demodulation method, the accuracy of the sine wave amplitude measurement is improved. By improving and multiplying the multi-channel measurements, the measurement of the amplitude sensed in multiple parts of the object can be accurately derived.

In addition, since the output sinusoidal signal 10 and the reference signal 12 are output based on the excitation signal of the common excitation power supply 110, even if there is noise in the excitation signal, the output sinusoidal signal 10, or the like, the immunity to such noise is strong. Can have characteristics.

Meanwhile, referring to FIGS. 1 and 5, a sine wave amplitude measuring method according to another exemplary embodiment of the present invention will be described. 5 is a diagram for describing a sine wave amplitude measuring method according to another exemplary embodiment of the present invention. An embodiment to be described later will be described mainly with respect to the sinusoidal amplitude measuring apparatus 100 of FIG. 1, but of course, the sinusoidal amplitude measuring apparatus 200 of FIG. 2 may also be applied by generating a reference signal independently of the excitation signal.

Another embodiment of the present invention, in addition to the case of measuring the amplitude of the output sinusoidal signal 20 smaller than the output sinusoidal signal 10 shown in the embodiment of Figures 3 and 4, A case of detecting the first cross time from the comparative square wave using a different method will be described.

First, in the case of measuring the amplitude of the small output sinusoidal wave signal 20, the method proceeds in substantially the same manner as in the measuring methods of FIGS. 3 and 4, but compares the square wave of the output by the second comparator 150 of FIG. The production process of 26) is different. In detail, the second comparator 150 may receive the small output sinusoidal wave signal 20 and the reference signal 22, and generate the comparison square wave 26 according to the comparison therebetween, as illustrated in FIG. 5. have. In this case, the output square wave signal 20 is compared so that the comparison square wave 26 of the second comparator 150 has the same absolute value (Vpp = 1) as that of the reference square wave 24 of the first comparator 140. It can be amplified to a larger value and output.

Compared to the conventional sinusoidal amplitude measuring method, the algorithm is simplified, so that the embodiment related to the measuring method is designed to be robust to the temperature sensitivity caused by the circuit implementing the same, even when measuring the output sinusoid 20 having a small amplitude. Multichannel measurements can be calculated more simply and accurately.

Next, when the first cross time is detected by a method different from the measurement method mentioned in the above description, the process proceeds substantially the same as the method described with reference to FIGS. 3 and 4, but the cross detection unit 150 of FIG. The process of calculating the first cross time t _h is different. This process enables more accurate measurements when the output sinusoidal signal 20 and the reference signal 22 maintain the Wide Sense Stationary (WSS) as much as possible. The cross detector 150 detects the comparative falling edge of the comparison square wave 26 existing within two periods 30 or more of the reference square wave 24 after the reference edge time t _r , thereby outputting the sine wave signal. Assume that 20 and reference signal 22 are equal to Vc, thereby calculating the first cross time t _h corresponding to the comparison falling edge in comparison square wave 26, as shown in FIG. Can be. By substituting the calculated first cross time t _h into the above expression (1), the amplitude of the output sinusoidal wave signal 20 can be measured.

According to the embodiment related to the measurement method according to this, it is possible to prevent the comparison edge of the comparison square wave 26 from causing an error in the measurement such as the first cross time t _h due to noise. Furthermore, in a situation where the time invariant state (WSS) is maintained, a high signal to noise ratio (SNR) can be obtained by measuring the first cross time t _h and the like by being spaced apart from the reference edge time t _r by more periods. can do. Therefore, according to this embodiment, the amplitude of the output sinusoidal wave signal 20 having a small amplitude and a period of high frequency can also be measured accurately.

A sinusoidal amplitude measuring apparatus and a measuring method according to another embodiment of the present invention will be described with reference to FIGS. 6 and 7. 6 is a block diagram of a sinusoidal amplitude measuring apparatus according to another embodiment of the present invention, and FIG. 7 is a diagram for describing a sinusoidal amplitude measuring method according to another embodiment of the present invention.

First, referring to FIG. 6, the sine wave amplitude measuring apparatus according to the present exemplary embodiment includes substantially the same components as those illustrated in FIGS. 1 and 2 except for the configuration of detecting the cross time. In the example, a configuration different from the embodiment of FIG. 1 will be mainly described. Specifically, the excitation power source 110, the signal detector 120, the phase delay unit 130, the first and second comparators 140 and 150, the reference detector 160, and the amplitude calculation described with reference to FIG. 1 are described. Functioning substantially the same as the unit 180, the cross detector 170 may have a configuration as follows.

After the reference edge time (see t _{r in} FIG. 7), the cross detector 170 outputs the output sinusoidal signal (see 32 in FIG. 7) and the reference signal (see 34 in FIG. 7) in the comparison square wave (see 38 in FIG. 7). Corresponds to a case where the output sinusoidal signal 32 and the reference signal 34 are the same after the first cross time detector 172 and the reference edge time t _r that detect the first cross time corresponding to The second cross time detector 174 may detect a second cross time different from the first cross time.

In detail, when at least one of the output sinusoidal signal 32 and the reference signal 34 is an offset signal, the cross detector 170 including the first and second cross time detectors 172 and 174 may be used. The amplitude of the output sinusoidal wave signal 32 can be measured using. Here, the offset of the output sinusoidal signal 32 and the reference signal 34 may include, for example, a noise voltage and the like in response to an excitation signal of the excitation power supply 110 and a signal of the signal detection unit 120 output through the object. The same extra signal may be added. The offset signal V _offset is the case of the output sinusoidal wave signal 32 shown in FIG. 7, and may be reflected substantially the same as the maximum and minimum values of the output sinusoidal wave signal 32, for example. In summary, in order to accurately measure the amplitude of the output sinusoidal signal 32 regardless of the offset signal unintentionally added to the output sinusoidal signal 32 and the reference signal 34, the first and second cross time detectors ( 172, 174 are provided.

The first cross time detector 170 refers to the reference edge time t _r output from the reference detector 160, and after this time t _r , a comparison square wave existing within a predetermined period of the reference square wave 36. By detecting the comparative falling edge of (38), it is possible to estimate that the output sinusoidal signal 32 and the reference signal 34 are equal to Vc ₁ , and the first cross time detection section 172 is the same as the comparison square wave 38. The first cross time t _c1 corresponding to the comparison falling edge may be calculated.

The second cross time detector 174 is within a predetermined period of the reference square wave 36 after the reference edge time t _r , and compares the comparison square waves 38 present after the first cross time t _c1 . By detecting the rising edge, the second cross time detector 174 may calculate a second cross time t _c2 corresponding to the comparison rising edge in the comparison square wave 38.

The amplitude calculating unit 180 is based on the angular frequency ω of the excitation signal, the known phase φ of the reference signal 34, the first cross time t _c1 , and the second cross time t _c2 . The amplitude of the sinusoidal wave signal 32 output from the signal detector 120 may be calculated, and a detailed algorithm thereof will be described later.

Hereinafter, referring to FIGS. 1, 6, and 7 again, a sinusoidal amplitude measuring method according to another embodiment of the present invention will be described using the sinusoidal amplitude measuring apparatus 100 shown in FIGS. 1 and 6. Shall be. The sinusoidal amplitude measurement apparatus 200 of FIG. 2 is also applicable, of course, by generating the reference signal independently of the excitation signal. For convenience of description, the signal detecting unit 120 is a sensor described through the embodiment of FIG. 1, and the object detected by the sensor may be a living tissue having a resistive component, and the like, and the excitation signal of the excitation power supply 110 may be sinωt ( Vpp = 1), and the reference signal 34 of the phase delay unit 130 is sin with the same angular frequency ω as the excitation signal but with a known phase difference φ (for example, 45 degrees as φ> 0). (ωt-φ) (Vpp = 1), and the output sinusoidal signal 32 of the signal detector 120 has a V _offset. As an example of the sinusoidal voltage signal offset by this, Xsinωt + V _offset (0 <X≤1) will be described as an example. That is, the case where only the output sinusoidal signal 32 is offset will be described as an example.

The reference edge time t _r , which is the time corresponding to the output sinusoidal signal 32, the reference signal 34 and the reference square wave 36, the comparison square wave 38, and the reference falling edge, is the signal detector 120, the phase delay. The sinusoidal amplitude measuring method according to an exemplary embodiment of the present invention described with reference to FIGS. 1, 3, and 4 through the unit 130, the first and second comparators 140 and 150, and the reference detector 160. Since it can be generated and obtained by a practical process, a description thereof will be omitted.

Subsequently, the first cross time detector 172 refers to the reference edge time t _r output from the reference detector 160, and after this time t _r , a predetermined period of the reference square wave 36, for example, 2. By detecting the comparative falling edge of the comparison square wave 38 present in the period, it can be estimated that the output sinusoidal signal 32 and the reference signal 34 are equal to V _C1 , and as shown in FIG. The cross time detector 172 may calculate a first cross time t _c1 corresponding to the comparison falling edge in the comparison square wave 38.

Subsequently, the second cross time detector 174 compares the first cross time t _c1 after being present within a predetermined period of the reference square wave 36, for example, two or more periods after the reference edge time t _r . By detecting the comparison rising edge existing within one period of the square wave 38, the second cross time detector 174 sets the second cross time t _c2 corresponding to the comparison falling edge in the comparison square wave 38 in FIG. 7. As shown, it can be calculated.

Next, the amplitude calculating unit 180 at the angular frequency ω of the excitation signal, the known phase φ of the reference signal 34, the first cross time t _c1 and the second cross time t _c2 . Based on this, X, which is the amplitude of the sine wave signal 32 output from the signal detector 120, can be calculated by the following equations (2) to (4). The amplitude X can be calculated from this, even though the angular frequency ω, the phase φ, the first cross time t _c1 and the second cross time t _c2 are already known and the V _offset is unknown. This is because it is erased as in Equation (4).

sin (ωt _c1 -φ) = Xsinωt _c1 + V _offset = V _C1 (2)

sin (ωt _c2 -φ) = Xsinωt _c2 + V _offset = V _C2 (3)

X = [sin (ωt _c1 -φ)-sin (ωt _c2 -φ)] / [sinωt _c1 sinωt _c2 (4)

Although only the output sinusoidal signal 32 has been described as being an offset signal, in the present embodiment, even if the output sinusoidal signal 32 and the reference signal 34 are all offset to different values, the offset is typically each signal 32. Since the offsets present in both signals 32 and 34 can be eliminated according to Equations (2) to (4), as they are substantially equally included in the maximum and minimum values of (34), It is possible.

The sinusoidal amplitude measuring apparatus according to the present invention is designed to simplify the circuit structure, compared to the conventional amplitude measuring method, thereby making it possible to measure the sine wave amplitude which is robust to the temperature sensitivity caused at the time of implementation and is simultaneously output from multiple parts of the object. It is optimized for multi-channel measurements for high accuracy. Further, according to the present embodiment, even if an offset signal is inadvertently added to the output sinusoidal signal 32 and the reference signal 34, it is not affected by this and can accurately measure the amplitude of the output sinusoidal signal 32. Algorithms can be implemented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by all changes or modifications derived from the scope of the appended claims and the appended claims.

100: sine wave amplitude measurement device 110: excitation power
120: signal detector 130: phase delay unit
140: first comparator 150: second comparator
160: reference detection unit 170: cross detection unit
180: amplitude calculator 230: reference power supply

Claims (7)

Receiving a sinusoidal signal applied from the outside;
Generating a reference signal outputting a sinusoidal wave having a known same period as the sinusoidal signal and having a known phase difference from the sinusoidal signal;
Generating a reference square wave synchronized with the comparison between the reference signal and a reference level;
Generating a comparison square wave synchronized with the sinusoidal signal and the reference signal;
Detecting a reference edge time corresponding to the reference signal and the reference level in the reference square wave;
After the reference edge time, detecting a first cross time corresponding to the case where the sinusoidal signal and the reference signal are the same in the comparison square wave; And
Calculating an amplitude of the sinusoidal signal based on the period, the known phase difference and the first cross time. The method of claim 1,
When at least one of the sinusoidal signal and the reference signal is an offset signal,
Before the calculating of the amplitude of the sinusoidal signal, after the reference edge time, detecting the second cross time different from the first cross time while corresponding to the case where the sinusoidal signal and the reference signal are the same; and,
The calculating of the amplitude of the sinusoidal signal comprises calculating the amplitude based on the period, the known phase difference, the first cross time, and the second cross time. The method of claim 1,
The sinusoidal signal is output from a sensor that senses characteristics of an object, and the sensor receives the sinusoidal signal output by applying an excitation signal having the same frequency and phase as the sinusoidal signal to the object through the sensor. Sine wave amplitude measurement method. The method of claim 3, wherein
And the reference signal is derived from the excitation signal and has a phase delayed from the phase of the excitation signal, or is generated independently of the excitation signal and has a phase delayed from the phase of the excitation signal. The method of claim 3, wherein
The object is a sine wave amplitude measurement method of living tissue. The method of claim 1,
The detecting of the reference edge time may include detecting a reference rising edge or a falling reference edge. The detecting of the first cross time may include after the reference edge time, the reference square wave. A sinusoidal amplitude measuring method for detecting a comparative rising edge or a falling falling edge of a comparative square wave existing within one period of or present in two or more cycles of the reference square wave. A signal detector configured to receive a sinusoidal signal applied from the outside;
A reference signal generator having a known period equal to the sinusoidal signal and generating a reference signal output as a sinusoidal wave having a known phase difference from the sinusoidal signal;
A first comparator configured to generate a reference square wave synchronized with the comparison between the reference signal and a reference level;
A second comparator configured to generate a comparison square wave synchronized with the comparison between the sinusoidal signal and the reference signal;
A reference detector configured to detect a reference edge time corresponding to the case where the reference signal and the reference level are the same in the reference square wave;
A cross detector configured to detect a first cross time corresponding to a case where the sinusoidal signal and the reference signal are the same in the comparison square wave after the reference edge time; And
And an amplitude calculator configured to calculate an amplitude of the sinusoidal signal based on the period, the known phase difference, and a first cross time.

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