KR200295156Y1 - Distance Detecting Circuit Having Temperature Correction Function - Google Patents

Abstract

The distance sensing circuit according to the present invention is a distance sensing circuit of a device that performs a predetermined task when a wireless transmission / reception unit enters a predetermined sensing distance, the antenna receiving an electric wave transmitted by the wireless transmission / reception unit, and A demodulation circuit for demodulating a radio wave received by an antenna, a signal level input section for receiving a signal level demodulated by the demodulation circuit and subjected to a predetermined signal processing, a temperature signal input section for receiving a value corresponding to an external temperature signal; And correcting the value input to the signal level input unit by the value input to the temperature signal input unit, and comparing the corrected signal level value with a predetermined reference value when the corrected signal level value is equal to or greater than a predetermined reference value. It includes a calculation processing unit to perform the predetermined task.

In this way, if the reference voltage is varied according to the temperature, the device for detecting the distance of the radio wave transmitter based on the strength of the signal transmitted by the portable radio transmitter is always constant and accurate even if the receiver changes its characteristics depending on the temperature. The error in detecting distance is severe. However, the present invention provides an effect of maintaining a constant and accurate sensing distance even in the case of such a temperature change.

Description

Distance Detecting Circuit Having Temperature Correction Function

The present invention relates to a distance sensing circuit for performing a predetermined task when a person or an object approaching through wireless communication enters a predetermined distance. In particular, the present invention always maintains a constant sensing distance regardless of temperature. The present invention relates to a distance sensing circuit.

As described above, a representative device for performing a task when a person or an object enters a predetermined distance is a wireless door locking device. In such a device, when a person possesses a portable wireless transmission / reception means, for example, a card type or a remote control type and approaches the door, the transmission device and the locking device mounted on the door communicate with each other wirelessly, and the person enters a predetermined sensing distance. Once confirmed, the lock is released. Such doors can be used for various purposes such as general residential buildings, office buildings, and vehicle doors.

Not only the door but also a device for driving a display device or performing various tasks when a person or an object enters a predetermined sensing distance, the sensing distance needs to be kept constant.

In the case of determining by radio communication whether a person or an object has entered within a sensing distance, it is often determined by comparing the strength of radio waves transmitted by the mobile unit and received by the floating device by comparison with a reference value. In this way, however, when the external temperature changes, the intensity of the received signal is generally changed. In this case, the sensing distance is jagged and constant because the comparison value between the reference value and the intensity of the received signal is not output constantly. There is a problem that can not be maintained.

The present invention is to solve this problem in the distance sensing device for performing a predetermined task when performing a distance detection through wireless communication and the wireless transmission and reception unit enters within a predetermined detection distance, An object of the present invention is to provide a distance sensing device that maintains a constant sensing distance at all times without being affected by external temperature.

1 is a block diagram of a distance sensing circuit according to a first embodiment of the present invention;

2 is a block diagram of a distance sensing circuit according to a second embodiment of the present invention;

3 is a block diagram of a distance sensing circuit according to a third embodiment of the present invention;

4 is a flowchart of temperature correction according to the present invention.

5 is a correction table for temperature correction according to the present invention.

The distance sensing circuit according to the first aspect of the present invention for achieving the object of the present invention is a distance sensing circuit of a device for performing a predetermined operation when the wireless transmission and reception unit enters within a predetermined sensing distance, the wireless transmission and reception An antenna for receiving the radio wave transmitted by the unit, a demodulation circuit for demodulating the radio wave received by the antenna, a signal level input section for receiving a signal level demodulated by the demodulation circuit and subjected to predetermined signal processing, and an external temperature. A signal corrected by correcting a value input to the signal level input unit by a temperature signal input unit receiving a value corresponding to a signal and a value input to the temperature signal input unit, and comparing the corrected signal level value with a predetermined reference value An arithmetic processor configured to perform the predetermined task when the level value is equal to or greater than a predetermined reference value; .

In the distance sensing circuit according to the second aspect of the present invention, the distance sensing circuit according to the first aspect includes: an A / D for converting a value input to the signal level input unit and a value input to a temperature signal input unit into a digital value; It further includes a conversion unit.

The distance sensing circuit according to the third aspect of the present invention further includes a display portion for displaying the corrected signal level value converted by the A / D converter into a digital value in the distance sensing circuit of the second aspect.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. An embodiment of the distance sensing circuit according to the present invention is described as being applied to a floating device that receives radio waves transmitted by a wireless transmitting / receiving unit such as a wireless transmitting / receiving card carried by a user, but the present invention is not only a floating device but also a mobile device. Regardless of whether the device receives a radio wave and enters a predetermined distance, any device that performs a predetermined task is a distance sensing circuit applicable to any device.

[First Embodiment]

1 is a block diagram of a distance sensing circuit according to a first embodiment of the present invention. The distance sensing circuit includes a microwave receiving antenna 150, a first band pass filter 2, a first amplifier 3, a mixer 4, and a second band for receiving microwaves transmitted by a wireless transmission / reception unit. A pass filter 5, a second amplifier 6, a detector 7, a first comparator 8, a first buffer amplifier 9, a voltage controlled oscillator 10, A loop filter 11, a reference oscillator 18, a phase detector 12, and a temperature sensor 50 are included. Such a distance sensing circuit adopts an amplitude shift key (ASK) demodulation circuit. In this embodiment, the case where the radio wave received through the reception antenna 15 is an ultra-short wave is described, but the present invention is not limited thereto. The same applies to the second and third embodiments below.

The signal received by the microwave receiving antenna 150 passes only the band set to receive while passing through the first band pass filter 2, and the rest of the signal is attenuated. For example, a surface acoustic wave filter may be used as the first band pass filter 2. The signal passing through the first band pass filter 2 is first amplified by the first amplifier 3 and enters the mixer 4 and is mixed with the local signal.

The frequency of the local signal is divided by the frequency oscillated by the voltage regulating oscillator 10 by 68 and compares this frequency with the frequency oscillated by the reference oscillator 18 with the phase of the phase detector 12 and outputs the difference. It is made by varying the frequency of the voltage adjusting oscillator 10 by making it the average voltage from which phase noise is removed in the loop filter. The value dividing the frequency oscillated by the voltage controlled oscillator 10 can be changed depending on the designer or the type of semiconductor used. The frequency Fo of the local signal is determined by the frequency Fs and the intermediate frequency Fi of the received signal. That is Fo = Fs-Fi.

The frequency of the signal passed through the first amplifier 3 and the local signal mixed in the mixer 4 is Fs, Fo, Fs + Fo, Fs-Fo, etc., and the signal is the second band pass filter 5 ), Only the signal of Fs-Fo frequency passes and the signal of the rest of the frequency does not pass and is attenuated. The signal passing through the second band pass filter 5 is amplified while passing through the second amplifier 6 and passes through the detector 7, leaving only the audio signal, which passes through the first comparator 8 and the digital signal. Is converted to. Since the converted signal has high impedance, data may be damaged by the line. Therefore, this signal is output as data after changing the impedance via the first buffer amplifier 9.

Determining whether or not the wireless transmitting / receiving unit that has transmitted the microwave is within a predetermined sensing distance detects a signal from the detector 7, removes noise by the low pass filter 13, and then inputs an input signal of the CPU 100. The temperature value of the target to be applied by the temperature sensor 50 is input to the CPU 100 as a voltage value corresponding to the temperature by the reference voltage generator using various temperature sensors. do.

The signal from the detector 7 is detected by a voltage or a received signal strength indicator (RSSI) voltage that varies with the strength of the signal.

The signal level input to the CPU 100 and the signal of the sensor are changed into a digital value through an A / D converting process in the CPU 100, and these two values are used to calculate the process by an internal processing table. After that, specific data is calculated. When data is received while the data satisfies a specific value or more, a predetermined task is performed in advance.

4 is a flowchart of a task performed by the CPU 100.

The CPU 100 periodically checks the data input port and if there is data to be input, the data receiving step is started (S1). When the data is received, it is verified whether the received data is a signal normally input through the wireless transmission / reception unit or a noise signal or data transmitted from another wireless device (S2). If it is determined that it is an external signal, the process proceeds to data reception wait (S12). If it is determined that the signal normally input through the wireless transceiver unit receives the data processed through the signal processing, the signal level input port receives the strength of the analog signal, for example, a voltage and converts the input value into A / D conversion. Through the conversion of the input voltage value into a digital value that can be processed in the CPU (100) (S4).

On the other hand, the sensor level input port receives an analog value for the current temperature, for example, a voltage, the digital that can also be processed in the CPU 100 through the A / D conversion inside the CPU 100 Convert to a value (S5).

Next, the signal level value is corrected by the sensor input value, which is corrected based on the predetermined processing table (S6).

For example, when the maximum value of the voltage signal input to the sensor input port is 5V and the resolution of the A / D converter of the CPU 100 is 8 bits, the digital value to be A / D converted is a value of 0 to 255. Will be taken. When calculated with these digital values, the voltage corresponding to one level is 0.0196V, which is approximately 0.02V.

Based on the numerical value, the following table is generated to calculate the correction value. The correction table can define a desired predetermined control value or display value by varying the range between the input minimum and maximum values.

The correction table as shown in FIG. 5 is a correction table when the change is large, but in the general case, the change does not change significantly with temperature, and generally shows a linear characteristic, but a non-linear characteristic is shown. A calibration table like 5 is necessary.

In the correction table of FIG. 5, a sensor input value is converted to a digital value at the top of the horizontal axis, and a signal level value is converted to a digital value at the leftmost side of the vertical axis. Is defined.

Subsequently, when the reference value is greater than the signal level correction value by comparing the corrected signal level value and the reference value, the process proceeds to the step of waiting for data reception (S12). When the corrected signal level value is equal to or greater than the reference value, the process proceeds to the next step. For example, in an apparatus for releasing a door lock when a wireless transmission / reception unit enters a predetermined sensing distance, when the sensing distance is set to 5 m and the reference signal level is set to 150, the correction value If it is equal to or greater than 150 it is possible to unlock the door lock.

The signal level value corrected in step S6 may be displayed numerically or in a graph. (S7) In this way, even in an apparatus for displaying the intensity of radio waves received using the signal level, it is corrected to a value input from a temperature sensor. After the process, by displaying the intensity of radio waves, it is possible to always display a constant display value even when there is a change in temperature.

For example, in the bar-shaped display that displays the transmission and reception sensitivity on the mobile phone display, if there are four bars at the maximum transmission and reception sensitivity, if the correction value is 0 to 50, the reception cannot be displayed, 51 to 100 is one bar, and 101 to 150 is the bar. Two, 151-200 can be represented by three bars and 201-255 by four bars.

In step S9, the received data is verified once again (S9), and when the verification is confirmed, the CPU 100 is controlled to recognize that the wireless transmission / reception unit has entered within a predetermined distance and perform a predetermined task. (S11) After the predetermined work is performed, the process proceeds to the data reception wait step S12.

If there is no A / D conversion function inside the CPU 100, the sensor input port is connected to the Vin terminal of the external A / D converter, and the data output terminal of the A / D converter is connected to the sensor input of the CPU 100. Connect to the port. The signal level input port is also connected to the signal level input port of the CPU 100 via an external A / D converter as above.

In this case, it is preferable that the output method of the A / D converter to be used generally reduces the use of the input port of the CPU 100 by using a converter that is output as a serial binary value. In addition, although an 8-bit sampling converter is generally used, a converter capable of sampling from 10 to 12 bits or more may be used for more detailed analysis.

Second Embodiment

2 is a block diagram of a distance sensing circuit according to a second embodiment of the present invention.

The distance sensing circuit according to the second embodiment includes an antenna 150 for receiving microwaves transmitted by a wireless transmission / reception unit, a first band pass filter 2, a first amplifier 3, a mixer 4, Local oscillator 20, second band pass filter 5, second amplifier 6, detector 7, first comparator 8, first buffer amplifier 9, signal voltage detector 21, the second comparator 14, the second buffer amplifier 15, and the reference voltage generator 16 are included. The same reference numerals are given to the same components as the circuit of the first embodiment.

The distance sensing circuit diagram of the second embodiment employs an amplitude biasing demodulation circuit as in the first embodiment.

The signal received by the antenna 150 passes only the band set to be received by the first band pass filter 2 and attenuates the rest. A surface acoustic wave filter may be used for the first band pass filter 2 as in the first embodiment. The signal passing through the first band pass filter 2 is amplified in the first amplifier 3 and mixed with the local signal in the mixer. The frequency of the local signal is generated using an X-TAL oscillator circuit or an LC oscillator circuit. The frequency Fo of the local signal is determined by the frequency Fs and the intermediate frequency Fi of the received signal. That is, local frequency Fo = reception frequency Fs-intermediate frequency Fi.

The signal received in this way and mixed with the local signal and the local signal, and the signal from the mixer 4 has a frequency of Fs, Fo, Fs + Fo, Fs-Fo, etc. The second band pass filter 5 Passing) will leave only the signal with frequency Fs-Fo and will attenuate the signal with the remaining frequency. The signal from the second band pass filter 5 is amplified by the second amplifier 6 and passed through the detector 7, leaving only the audio signal, which is passed through the first comparator 8 to a digital signal. This signal is again output through the first buffer amplifier 9 in order to prevent the characteristic of the first comparator 8 from changing externally.

On the other hand, the audio signal from the detector 7 is converted into a DC signal that changes according to amplitude, and is then used by the signal voltage detector 21 for automatic gain control (AGC) of the primary and secondary amplifier stages. . This signal is input to the port for inputting the strength of the input signal to the CPU 100, the temperature value of the target to be applied by the temperature sensor 50 is a reference voltage generation circuit using the various temperature sensors in the CPU 100 It inputs by the voltage value corresponded to temperature.

4 is a flowchart of a task performed by the CPU 100.

The CPU 100 periodically checks the data input port and if there is data to be input, the data receiving step is started (S1). When the data is received, it is verified whether the received data is a signal normally input through the wireless transmitting / receiving unit or a noise signal or data transmitted from another wireless device (S2). If it is determined that it is an external signal, the process proceeds to data reception wait (S12). If it is determined that the signal normally input through the wireless transceiver unit receives the data processed through the signal processing, the signal level input port receives the strength of the analog signal, for example, a voltage and converts the input value into A / D conversion. Through the conversion of the input voltage value into a digital value that can be processed in the CPU (100) (S4).

On the other hand, the sensor level input port receives an analog value for the current temperature, for example, a voltage, the digital that can also be processed in the CPU 100 through the A / D conversion inside the CPU 100 Convert to a value (S5).

Next, the signal level value is corrected by the sensor input value, which is corrected based on the predetermined processing table (S6).

For example, when the maximum value of the voltage signal input to the sensor input port is 5V and the resolution of the A / D converter of the CPU 100 is 8 bits, the digital value to be A / D converted is a value of 0 to 255. Will be taken. When calculated with these digital values, the voltage corresponding to one level is 0.0196V, which is approximately 0.02V.

Based on the numerical value, the following table is generated to calculate the correction value. The correction table can define a desired predetermined control value or display value by varying the range between the input minimum and maximum values.

The correction table as shown in FIG. 5 is a correction table when the change is large, but in the general case, the change does not change significantly with temperature, and generally shows a linear characteristic, but a non-linear characteristic is shown. A calibration table like 5 is necessary.

In the correction table of FIG. 5, a sensor input value is converted to a digital value at the top of the horizontal axis, and a signal level value is converted to a digital value at the leftmost side of the vertical axis. Is defined.

Subsequently, when the reference value is greater than the signal level correction value by comparing the corrected signal level value and the reference value, the process proceeds to the step of waiting for data reception (S12). When the corrected signal level value is equal to or greater than the reference value, the process proceeds to the next step. For example, in an apparatus for releasing a door lock when a wireless transmission / reception unit enters a predetermined sensing distance, when the sensing distance is set to 5 m and the reference signal level is set to 150, the correction value If it is equal to or greater than 150 it is possible to unlock the door lock.

The signal level value corrected in step S6 may be displayed numerically or in a graph. (S7) In this way, even in an apparatus for displaying the intensity of radio waves received using the signal level, it is corrected to a value input from a temperature sensor. After the process, by displaying the intensity of radio waves, it is possible to always display a constant display value even when there is a change in temperature.

For example, in the bar-shaped display that displays the transmission and reception sensitivity on the mobile phone display, if there are four bars at the maximum transmission and reception sensitivity, if the correction value is 0 to 50, the reception cannot be displayed, 51 to 100 is one bar, and 101 to 150 is the bar. Two, 151-200 can be represented by three bars and 201-255 by four bars.

In step S9, the received data is verified once again (S9), and when the verification is confirmed, the CPU 100 is controlled to recognize that the wireless transmission / reception unit has entered within a predetermined distance and perform a predetermined task. (S11) After the predetermined work is performed, the process proceeds to the data reception wait step S12.

If there is no A / D conversion function inside the CPU 100, the sensor input port is connected to the Vin terminal of the external A / D converter, and the data output terminal of the A / D converter is connected to the sensor input of the CPU 100. Connect to the port. The signal level input port is also connected to the signal level input port of the CPU 100 via an external A / D converter as above.

In this case, it is preferable that the output method of the A / D converter to be used generally reduces the use of the input port of the CPU 100 by using a converter that is output as a serial binary value. In addition, although an 8-bit sampling converter is generally used, a converter capable of sampling from 10 to 12 bits or more may be used for more detailed analysis.

Third Embodiment

7 is a block diagram of a distance sensing circuit according to a third embodiment of the present invention.

The distance sensing circuit of the third embodiment includes a microwave receiving antenna 150, a first band pass filter 2, a first amplifier 3, a mixer 4, for receiving microwaves transmitted by a wireless transmission / reception unit, A second band pass filter 5, a voltage controlled oscillator 10, a loop filter 11, a reference oscillator 18, a phase detector 12, a temperature And a sensing sensor 50.

The signal received through the antenna 150 is mixed with the local signal in the mixer 4 and passed through the second band pass filter 5 as in the first embodiment. The third embodiment differs from the first embodiment in that the signal from the second band pass filter 5 enters an intermediate frequency demodulator 40 (IF Demodulator).

The signal entering the intermediate frequency demodulator 40 is amplified by an amplifier stage inside the demodulator 40 and mixed with the signal of the frequency generated by the local oscillator 21, which is then mixed with the third band pass filter. The signal is converted into a signal having a predetermined band frequency by 30, detected by a discriminator or a tuning circuit, and an audio signal is output. The signal is converted into a digital signal by an amplifier inside the demodulator 40 and output.

On the other hand, there is an RSSI signal in the output of the intermediate frequency demodulator 40, which is input to the port for inputting the strength of the input signal of the CPU 100, the temperature value of the object to be applied by the temperature sensor 50 is the CPU The reference voltage generation circuit using various temperature sensors is input to the voltage value corresponding to the temperature.

4 is a flowchart of a task performed by the CPU 100.

The CPU 100 periodically checks the data input port and if there is data to be input, the data receiving step is started (S1). When the data is received, it is verified whether the received data is a signal normally input through the wireless transmitting / receiving unit or a noise signal or data transmitted from another wireless device (S2). If it is determined that it is an external signal, the process proceeds to data reception wait (S12). If it is determined that the signal normally input through the wireless transceiver unit receives the data processed through the signal processing, the signal level input port receives the strength of the analog signal, for example, a voltage and converts the input value into A / D conversion. Through the conversion of the input voltage value into a digital value that can be processed in the CPU (100) (S4).

On the other hand, the sensor level input port receives an analog value for the current temperature, for example, a voltage, the digital that can also be processed in the CPU 100 through the A / D conversion inside the CPU 100 Convert to a value (S5).

Next, the signal level value is corrected by the sensor input value, which is corrected based on the predetermined processing table (S6).

For example, when the maximum value of the voltage signal input to the sensor input port is 5V and the resolution of the A / D converter of the CPU 100 is 8 bits, the digital value to be A / D converted is a value of 0 to 255. Will be taken. When calculated with these digital values, the voltage corresponding to one level is 0.0196V, which is approximately 0.02V.

Based on the numerical value, the following table is generated to calculate the correction value. The correction table can define a desired predetermined control value or display value by varying the range between the input minimum and maximum values.

The correction table as shown in FIG. 5 is a correction table when the change is large, but in the general case, the change does not change significantly with temperature, and generally shows a linear characteristic, but a non-linear characteristic is shown. A calibration table like 5 is necessary.

In the correction table of FIG. 5, a sensor input value is converted to a digital value at the top of the horizontal axis, and a signal level value is converted to a digital value at the leftmost side of the vertical axis. Is defined.

Subsequently, when the reference value is greater than the signal level correction value by comparing the corrected signal level value and the reference value, the process proceeds to the step of waiting for data reception (S12). When the corrected signal level value is equal to or greater than the reference value, the process proceeds to the next step. For example, in an apparatus for releasing a door lock when a wireless transmission / reception unit enters a predetermined sensing distance, when the sensing distance is set to 5 m and the reference signal level is set to 150, the correction value If it is equal to or greater than 150 it is possible to unlock the door lock.

The signal level value corrected in step S6 may be displayed numerically or in a graph. (S7) In this way, even in an apparatus for displaying the intensity of radio waves received using the signal level, it is corrected to a value input from a temperature sensor. After the process, by displaying the intensity of radio waves, it is possible to always display a constant display value even when there is a change in temperature.

For example, in the bar-shaped display that displays the transmission and reception sensitivity on the mobile phone display, if there are four bars at the maximum transmission and reception sensitivity, if the correction value is 0 to 50, the reception cannot be displayed, 51 to 100 is one bar, and 101 to 150 is the bar. Two, 151-200 can be represented by three bars and 201-255 by four bars.

In step S9, the received data is verified once again (S9), and when the verification is confirmed, the CPU 100 is controlled to recognize that the wireless transmission / reception unit has entered within a predetermined distance and perform a predetermined task. (S11) After the predetermined work is performed, the process proceeds to the data reception wait step S12.

If there is no A / D conversion function inside the CPU 100, the sensor input port is connected to the Vin terminal of the external A / D converter, and the data output terminal of the A / D converter is connected to the sensor input of the CPU 100. Connect to the port. The signal level input port is also connected to the signal level input port of the CPU 100 via an external A / D converter as above.

In this case, it is preferable that the output method of the A / D converter to be used generally reduces the use of the input port of the CPU 100 by using a converter that is output as a serial binary value. In addition, although an 8-bit sampling converter is generally used, a converter capable of sampling from 10 to 12 bits or more may be used for more detailed analysis.

The scope of the present invention is not limited to the configuration of the above-described embodiment, but is determined by the appended claims, and as long as it includes the technical idea of the present invention, the improvement or modification technology of the invention described in the claims is also It is obvious that it belongs to the scope of the invention.

According to the present invention, since it becomes possible to maintain a constant sensing distance at all times without being influenced by temperature, a sensing distance which becomes a threshold point at which the operation is performed in a device which performs a preset task when entering within a predetermined sensing distance. The effect is always kept constant.

Claims (3)

Of a device performing a predetermined task when the wireless transmission / reception unit enters within a predetermined sensing distance. In the distance sensing circuit, An antenna for receiving radio waves transmitted by the radio transceiver unit; A demodulation circuit for demodulating a radio wave received by the antenna; A signal level input unit for receiving a signal level demodulated by the demodulation circuit and subjected to predetermined signal processing; A temperature signal input unit for receiving a value corresponding to an external temperature signal; Correcting the value input to the signal level input unit by the value input to the temperature signal input unit, And a calculation processing unit for comparing the corrected signal level value with a predetermined reference value to perform the predetermined operation when the corrected signal level value is equal to or greater than the predetermined reference value. The distance sensing circuit of claim 1, further comprising an A / D converter configured to convert a value input to the signal level input unit and a value input to the temperature signal input unit into a digital value. The distance sensing circuit according to claim 2, further comprising a display unit for displaying a corrected signal level value converted into a digital value by the A / D converter.