JP2000124729A - Communication device and small-sized portable communication device provided with range finding means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform optimum communication by estimating an object for affecting antenna characteristics most among the objects positioned near an antenna and adjusting matching conditions corresponding to antenna characteristic change by the object. SOLUTION: A portable telephone set is provided with an antenna 1, a matching circuit 3 for matching impedance with the antenna 1, a distance measurement means 7 for measuring the distance between the antenna 1 and the object 10 by ultrasonic waves and a control means 5 as a circuit condition adjustment means for adjusting the matching circuit conditions of the matching circuit 3 corresponding to the distance measured in the distance measurement means 7, the size of reflected ultrasonic waves and a priority coefficient. That is, it is estimated that the one for which the multiplied result (judgement factor) of the distance, the size of the reflected ultrasonic waves and the priority coefficient is maximum is the object for most affecting the antenna 1. The control means 5 sets the matching conditions calculated beforehand to the antenna matching circuit 3 corresponding to the one of the maximum judgement factor. The ultrasonic waves reduce effect on the head part of a human body and measure the distance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus having an antenna for measuring a distance of an object located near an antenna and adjusting an antenna characteristic which changes according to the measured position. Further, the present invention relates to a small portable communication device having a distance measuring means.

[0002]

2. Description of the Related Art As a communication device, a small portable communication device, for example, a portable telephone will be described as an example. Since the mobile phone is used close to the head of the person who talks, the antenna provided on the mobile phone and the human head approach. As a result, in addition to radio wave absorption in the human head,
The reflected power at the antenna feed point increases or decreases due to the coupling relationship between the human head, the antenna, and the head, and the antenna characteristics change.

[0003]

SUMMARY OF THE INVENTION In a portable telephone,
It is assumed that the human head and the antenna are used close to each other, and a circuit design has been made in consideration of the change in antenna characteristics as described above.

However, a standard circuit design is made under the condition that the distance between the human head and the antenna is within a certain range, and the standard circuit design changes according to the change in the distance between the antenna and the human head. There is no design to operate the mobile phone under optimal circuit conditions taking into account the change in antenna characteristics.
Therefore, when making a call of better quality, it is desirable to adjust the circuit conditions in consideration of antenna characteristics according to the distance between the antenna and the human head.

[0005] In the above, a case where a telephone call is performed using a mobile phone has been described. However, a similar problem occurs when data communication is performed using a mobile phone. In that case, it is not limited to the antenna of the mobile phone and the human head. For example, the presence of a metal object that absorbs radio waves near the antenna affects communication quality. In such a case, it is desirable to adjust the circuit conditions of the mobile phone according to the change in the antenna characteristics.

In such an adjustment, it is necessary to measure the distance between the antenna and an object in the vicinity of the antenna and adjust circuit conditions according to the measured distance. There is no known distance measuring means that has little influence, is inexpensive, is small, can operate stably for a long period of time, and can mount (store) a mobile phone.

[0007] In the above example, a mobile phone is illustrated as a communication device. However, other fixed transmission devices that perform communication using an antenna also encounter the same problem as described above.

[0008] In order to overcome the above-mentioned problems, an object of the present invention is to provide a small-sized communication device such as a portable telephone, which has a small effect on the human body, is inexpensive, small in size, and can operate stably for a long period of time. In particular, it is an object of the present invention to provide a communication device which has a distance measuring means which can be mounted thereon, and in particular, detects an object which substantially affects antenna characteristics and adjusts circuit conditions based on the detection result. Another object of the present invention is to provide a small portable communication device having a distance measuring means and a means for adjusting circuit conditions.

[0009]

According to the present invention, an antenna, a matching circuit for impedance matching with the antenna, and a distance between the antenna and an object are measured by ultrasonic waves to estimate the size of the object. Then, the measured distance, the estimated size of the object, and, by multiplying the priority coefficient based on the receiving order of the ultrasonic reflected waves, to calculate an evaluation value affecting the antenna characteristics, according to the evaluation value A communication device having a circuit condition adjusting unit for adjusting a matching circuit condition of the matching circuit is provided.

Preferably, the circuit condition adjusting means estimates the size of the object from a time difference between a rise time and a fall time of the ultrasonic reflected wave and the measured distance. Also preferably, the circuit condition adjusting means includes:
The size of the object is estimated from the integration result of the envelope detection signal of the ultrasonic reflected wave and the measured distance.

Preferably, the circuit adjusting means includes a distance measuring means and a matching condition adjusting means, and the distance measuring means includes a transmitting ultrasonic sensor provided in the communication device, and a transmitting ultrasonic sensor provided in the communication device. An ultrasonic sensor for reception provided;
An excitation unit that excites the transmission ultrasonic sensor provided in the communication device, and the ultrasonic wave emitted from the transmission ultrasonic sensor provided in the communication device is reflected by the object and is reflected. The ultrasonic wave is received by the receiving ultrasonic sensor, and the time from transmission of the ultrasonic wave to reception of the ultrasonic wave is measured, and from the measurement time, the ultrasonic sensor for transmission or the ultrasonic sensor for reception to the object. Ultrasonic distance measuring means for measuring the distance of, the matching condition adjusting means, the measured distance, the estimated size of the object, and a priority coefficient based on the receiving order of ultrasonic reflected waves A computer that calculates an evaluation value that affects the antenna characteristics by multiplying the same and adjusts a matching circuit condition of the matching circuit according to the evaluation value.

Specifically, the communication device is a small portable communication device.

According to the present invention, the transmitting ultrasonic sensor, the receiving ultrasonic sensor, the exciting means for exciting the transmitting ultrasonic sensor, and the ultrasonic wave radiated from the transmitting ultrasonic sensor are provided. The ultrasonic wave reflected by the object is received by the ultrasonic sensor for reception, the time from transmission of ultrasonic wave to reception of ultrasonic wave is measured, and the ultrasonic sensor for transmission or the reception is measured from the measurement time. Ultrasonic distance measuring means for measuring the distance from the ultrasonic sensor for use to the object, and estimating the size of the object, receiving the measured distance, the estimated object size, and the ultrasonic reflected wave A small portable communication having circuit condition adjusting means for calculating an evaluation value affecting antenna characteristics by multiplying the priority coefficient based on the order and adjusting a matching circuit condition of the matching circuit according to the evaluation value; Device It is subjected.

Preferably, the transmitting ultrasonic sensor includes:
The ultrasonic sensor for reception is integrally formed.

In the communication device according to the present invention, the distance between an antenna mounted on the communication device and an object located near the antenna is measured using ultrasonic waves, and the size of the object is estimated. Considering the measured distance, the estimated size of the object and the reception order of the received ultrasonic reflected waves, the one that substantially changes the antenna characteristics or the one that changes the antenna characteristics the most is estimated, and the estimation is performed. Adjust circuit conditions according to the result.

Ultrasound has little effect on the human body. Therefore, for example, even if the communication device is a mobile phone and the object is the head of the human body used close to the mobile phone, the distance between the antenna and the head of the human body is measured with little effect on the human body. it can. Ultrasonic waves are also suitable for detecting objects in communication devices other than mobile phones.

The transmitting ultrasonic sensor, the receiving ultrasonic sensor, the exciting means for exciting the transmitting ultrasonic sensor, and the ultrasonic distance measuring means are small, and can be easily mounted (accommodated) in a small communication device such as a mobile phone. ). The use of an integrated transmission ultrasonic sensor and reception ultrasonic sensor further reduces the size and weight.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 shows a communication device according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a transmission portion of a small portable communication device, for example, a mobile phone. The mobile phone illustrated in FIG. 1 includes an antenna 1, a matching circuit 3 that performs impedance matching with the antenna, a control unit 5, and an ultrasonic distance measuring unit 7. Control means 5 and ultrasonic distance measuring means 7
Correspond to the circuit condition adjusting means of the present invention described later.

The portable telephone further has an input filter 11, a high-frequency amplifier circuit 13, a frequency conversion circuit 15, and a data reproduction circuit 17 as a reception system. The mobile phone also includes, as a transmission system, an output filter 21, a high-frequency amplification circuit 23, a frequency conversion circuit 25, and a data generation circuit 27.
Having. Although an actual mobile phone has various circuits and means in addition to the one illustrated in FIG. 1, FIG. 1 illustrates only parts related to the present invention.

The portable telephone is, for example, a widely used portable telephone 30 as illustrated in FIG. 2, and an antenna 1 mounted on the portable telephone 30 is telescopic and can be accommodated in the portable telephone 30. This is a transmission / reception rod antenna used for both transmission and reception.

The data reception operation of the circuit illustrated in FIG. 1 will be described. The high frequency signal received by the antenna 1 is matched (impedance matching) in the antenna matching circuit 3 and is input to the input filter 11 to remove a noise component. The output signal of the input filter 11 is amplified in the high-frequency amplifier circuit 13 and converted to an intermediate frequency signal in the frequency conversion circuit 15. Thereafter, the frequency may be further converted, but is omitted in the illustrated mobile phone. Thereafter, the data is demodulated by a demodulation circuit (not shown), and the data is reproduced by the data reproduction circuit 17.
The voice is output from the voice output unit of the mobile phone as voice.

The data transmission operation of the circuit illustrated in FIG. 1 will be described. After the audio signal from the microphone of the mobile phone is converted into an electric signal, the data generation circuit 27 generates a call signal. Further, the signal is modulated in a modulation circuit (not shown), converted into a high frequency signal in a frequency conversion circuit 25, and amplified to a transmittable power level in a high frequency amplifier circuit 23. Further, the noise component is removed by the output filter 21 and applied to the antenna 1 via the antenna matching circuit 3 and radiated into the air.

The present inventor has found that the distance between the portable telephone and the head of the human body and the ratio of the high frequency absorbed power of the human body can be represented as a graph illustrated in FIG. Further, as illustrated in FIG. 3, the inventor of the present invention differs in the power absorption ratio depending on the distance between the antenna 1 (mobile phone 30) and the head of the human body. It has been found that by appropriately adjusting the matching condition, it is possible to maintain high communication quality.

Then, as illustrated in FIG. 2, the inventor of the present invention measures the distance between the antenna 1 and the measured object (object) 10 such as a human body by the ultrasonic distance measuring means 7,
The control means 5 changes the matching condition of the antenna matching circuit 3 based on the distance measurement result by the ultrasonic distance measuring means 7 so that an appropriate matching condition can be adjusted according to the distance between the antenna 1 and the object 10 to be measured. And

For this reason, the inventor of the present application previously obtains the circuit conditions of the antenna matching circuit 3 according to the distance between the antenna 1 and the measured object (object) 10 based on the characteristic curve of FIG. The result was stored in the means 5. The control means 5 has a built-in computer, preferably a microcomputer, and stores the results in a ROM. The antenna matching circuit 3 includes a plurality of switches and a plurality of matching circuits. One matching circuit selected by operating a switch according to a switching command from the control unit 5 can be connected to the antenna 1. It is configured in. Control means 5
Determines which matching circuit in the antenna matching circuit 3 is to be selected according to the distance measurement result of the ultrasonic distance measuring means 7,
One of a plurality of switches in the antenna matching circuit 3 is selectively driven. As a result, the selected matching circuit and the antenna 1 are connected.

As illustrated in FIG. 2, the ultrasonic distance measuring means 7 is incorporated (mounted) in the mobile phone 30. FIG. 4 is a schematic configuration diagram of the ultrasonic distance measuring means 7 mounted on the mobile phone 30, and FIG. 5 is a configuration diagram of the receiver 72 illustrated in FIG.
(E) is a graph illustrating the operation of the ultrasonic distance measuring means 7 illustrated in FIGS. 4 and 5.

The ultrasonic distance measuring means 7 illustrated in FIG.
A transmitting side having an ultrasonic transmitter 71, a transmitting ultrasonic sensor 73, and a transmitting horn antenna 75; a receiving side having an ultrasonic receiver 72, a receiving ultrasonic sensor 73, and a receiving horn antenna 74; 77.

In the illustrated configuration, a transmission horn antenna 75 and a reception horn antenna 76 are used to minimize noise around the distance measurement environment. Further, the reflected ultrasonic waves are focused using the receiving horn antenna 76. However, since the distance between the mobile phone 30 and the head of the human body is short, the antennas 75 and 76 can be omitted.

Since the ultrasonic sensor can be used for both transmission and reception, the ultrasonic sensor 73 for reception and the horn antenna 74 for reception can be used as one ultrasonic sensor. In that case, the transmission mode and the reception mode may be used separately in time. However, in the following description, an example in which the receiving ultrasonic sensor 73 and the receiving horn antenna 74 are separately provided will be described. The center axis of the transmitting ultrasonic sensor 73 (or the central axis of the directivity of the transmitting horn antenna 75) and the central axis of the ultrasonic sensor 74 for receiving (or the central axis of the directivity of the receiving horn antenna 76) are aligned. Is preferably as close to 0 as possible.

As the transmission ultrasonic sensor 73, a piezoelectric ceramic type ultrasonic sensor, for example, a piezoelectric sensor such as lithium niobate can be used. Similarly to the transmission ultrasonic sensor 73, the reception ultrasonic sensor 74 can use a piezoelectric ceramic ultrasonic sensor, for example, a piezoelectric sensor such as lithium niobate.

The method of measuring the distance in the ultrasonic distance measuring means 7 illustrated in FIG. 4 will be described. The control unit 77 controls the transmission timing of the ultrasonic transmitter 71 and the reception timing of the ultrasonic receiver 72. The control unit 77 first sets the transmission mode. At the transmission timing, the ultrasonic transmitter 71 excites the transmission ultrasonic sensor 73 to generate ultrasonic waves from the transmission ultrasonic sensor 73. The ultrasonic wave from the transmission ultrasonic sensor 73 is transmitted to the transmission horn antenna 75.
Is directed toward the object (object) 10 to be measured, and hits the object (object) 10 to be measured. The control unit 77 sets the reception mode. At the reception timing, the ultrasonic wave reflected by the object to be measured (object) 10 is incident on the ultrasonic sensor for reception 74 via the horn antenna 76 for reception, and the ultrasonic sensor for reception 74 detects the level of the incident ultrasonic wave. And outputs an electric signal corresponding to. The ultrasonic receiver 72 includes a transmitting ultrasonic sensor 73 that emits ultrasonic waves and a receiving ultrasonic sensor 74.
The time until reception is measured in step (1), and the distance between the measured object (object) 10 and the transmission ultrasonic sensor 73 is calculated from the measurement time. The distance L1 to be measured can be calculated based on the following equation.

L1 = (V × S) / 2 (1) where V is the propagation speed of the ultrasonic wave in the air at the temperature t. V = 331.5 + 0.6t (m / sec) S is the time from the start of the oscillation of the transmitting ultrasonic sensor 73 to the time when the receiving ultrasonic sensor 74 receives the first reflected wave.

The temperature at the time of this measurement is measured with respect to a reference temperature, for example, the propagation speed of the ultrasonic wave at t = 20 ° C. The propagation velocity V of the ultrasonic wave at t = 20 ° C. is 3
32.7 (m / sec).

In the transmission / reception separated reflection type ultrasonic distance measuring apparatus illustrated in FIG. 4, the transmission ultrasonic sensor 73 and the reception ultrasonic sensor 74 are drip-proof ultrasonic sensors for withstanding outdoor wind and rain. It is preferable to use Since the drip-proof type ultrasonic sensor is provided with a cover, when passing through the cover, attenuation occurs to reduce the overall gain. Therefore, the transmission ultrasonic sensor 73
When a drip-proof ultrasonic sensor is used as the receiving ultrasonic sensor 74, the distance measurement range becomes short. However,
When the measured object (object) 10 is a human body, that is sufficient. Usually, the object to be measured (object) 10 and the mobile phone 3
This is because the distance from 0 is about several cm to about several tens cm. However, it is desirable to perform more accurate distance measurement, and it is preferable to perform sensitivity correction.

The ultrasonic receiver 72 which has also performed such sensitivity correction will be described. FIG. 5 is a diagram mainly illustrating the circuit configuration of the ultrasonic receiver 72 in the ultrasonic distance measuring means 7. The ultrasonic receiver 72 includes a preamplifier / buffer circuit 720, a high-frequency signal filtering circuit 722, a ranging sensitivity correction circuit 724, a low-frequency signal filtering circuit / buffer circuit 72.
6, detection circuit 728, buffer circuit / comparison circuit 730,
A distance measurement calculation control circuit 732 is provided.

Prior to the actual distance measurement operation, the distance measurement operation control circuit 732 generates ultrasonic sensor sensitivity correction data for sensitivity correction in the distance measurement sensitivity correction circuit 724, and based on the ultrasonic sensor sensitivity correction data. In the distance measurement sensitivity correction circuit 724, the sensitivity of the received ultrasonic signal is corrected. Therefore, ultrasonic sensor sensitivity correction data used in the distance measurement sensitivity correction circuit 724 is collected in advance. The method is described below. Driving the transmission ultrasonic sensor 73,
In a state where the sensitivity correction is not performed in the distance measurement sensitivity correction circuit 724, a temporary distance is measured in the distance measurement calculation control circuit 732 from the reception signal of the reception ultrasonic sensor 74. The distance measurement arithmetic control circuit 732 generates the obtained temporary distance and the ultrasonic sensor sensitivity correction data to be performed by the distance measurement sensitivity correction circuit 724, and sets the data in the distance measurement sensitivity correction circuit 724. The transmission ultrasonic sensor 73 is driven again. The signal received by the receiving ultrasonic sensor 74 is a distance measurement sensitivity correction circuit 724.
Is subjected to sensitivity correction. The reception signal whose sensitivity has been corrected is detected by a detection circuit 728, and the detection signal is passed through a buffer circuit / comparison circuit 730 to a distance measurement calculation control circuit 7.
32, and the distance measurement calculation control circuit 732 calculates the actual distance from the time from transmission of the ultrasonic wave from the transmission ultrasonic sensor 73 to reception of the reflected wave by the reception ultrasonic sensor 74 according to Equation 1.

The distance measurement operation control circuit 732 performs an operation control unit (CPU) 7320 to perform the above-described processing.
A crystal oscillation circuit 7321 as a clock oscillator of the arithmetic and control unit 7320;
, A NAND gate 7325, a reset pulse generation circuit 7327, a latch pulse generation circuit 7329, and a distance measurement pulse generation circuit 7331. Ultrasonic receiver 72
Further includes a carrier generation circuit 7242, a timing pulse generation circuit 7244, and a power amplification circuit 7246. In this example, the carrier generation circuit 7242
Generates a 40 KHz carrier.

FIGS. 6A to 6E are signal waveform diagrams for explaining operations related to the buffer circuit / comparison circuit 730, the distance measurement operation control circuit 732, and the ultrasonic transmitter 71.

The timing pulse generating circuit 7244 generates a timing pulse at a predetermined period as illustrated in FIG. 6A, and the carrier generating circuit 7242 generates a carrier of 40 KHz according to the timing pulse. This carrier is illustrated in FIG. However, FIG.
Is applied from the carrier generation circuit 7242 to the buffer circuit 7323, and the buffer circuit 732
3 shows a waveform gated by the gate signal from the buffer circuit / comparison circuit 730. The power amplification circuit 7246 amplifies the carrier from the carrier generation circuit 7242 to a level at which the transmission ultrasonic sensor 73 can be driven. The carrier amplified by the power amplification circuit 7246 drives the transmission ultrasonic sensor 73 and emits an ultrasonic wave toward the measured object (object) 10 (FIG. 6C).

The ultrasonic wave reflected by the measured object (object) 10 is received by the receiving ultrasonic sensor 74 via the receiving horn antenna 76 (FIG. 6C shows the waveform of the reflected wave). Are applied to the ultrasonic receiver 72. The preamplifier / buffer circuit 720 amplifies a weak electric signal from the receiving ultrasonic sensor 74 to a predetermined level at which signal processing can be performed by a subsequent circuit. The high-frequency signal filtering circuit 722 allows the high-frequency component of the signal corresponding to the reflected ultrasonic wave amplified by the pre-amplifier / buffer circuit 720 to pass, and removes the low-frequency component. Thereby, the measured object (object) 10
The low frequency noise included in the reflected ultrasonic wave from can be removed.
The ranging sensitivity correction circuit 724 has a variable gain amplifier circuit and corrects the sensitivity of the signal from the high frequency signal filtering circuit 722. This will be described in detail below. The low-frequency signal filtering circuit / buffer circuit 726 includes a detection circuit 7 in the subsequent stage.
The low frequency signal component of the output signal from the ranging sensitivity correction circuit 724 is passed so that detection can be performed at 28. The detection circuit 728 includes a low-frequency signal filtering circuit / buffer circuit 726.
The output signal from is detected. As detection in the detection circuit 728, for example, envelope detection is performed. In this example, double detection is performed. The buffer circuit / comparison circuit 730 sequentially stores the continuous signal detected by the detection circuit 728 as digital data, and compares it with a predetermined level signal, and when the received reflected wave is higher than a predetermined level, a desired reflected wave is output. It outputs a signal indicating that it has been received.

The distance measurement calculation control circuit 732 receives the ultrasonic oscillation from the transmission ultrasonic sensor 73,
The time until the reception of the reception wave by the comparison circuit 730 is measured, and the distance is calculated according to Equation 1. Further, the distance measurement calculation control circuit 732 performs the distance measurement sensitivity correction in cooperation with the distance measurement sensitivity correction circuit 724. The details are described below.

When the transmission ultrasonic sensor 73 oscillates, the reset pulse generation circuit 7327
The reset pulse Rp is output to the arithmetic and control unit 7320 based on the timing pulse from the H.323,
The counter in 320 is reset. The reset counter then starts counting the gated carrier pulse (FIG. 6B) obtained by logically operating the carrier output from the distance measuring pulse generation circuit 7331 with the timing pulse from the buffer circuit 7323 by the NAND gate 7325. I do. When the buffer circuit / comparison circuit 730 determines that the received wave is a valid reflected wave, the buffer circuit / comparison circuit 7
30 outputs the pulse signal illustrated in FIG. 6E to the arithmetic control unit 7320 and the buffer circuit 7323.
The latch pulse generation circuit 7329 includes a buffer circuit 7323.
The latch pulse Lp in response to the pulse signal from the CPU.
7320 to stop counting by the counter. The count value of this counter is the time required for the transmission ultrasonic sensor 73 to oscillate ultrasonic waves toward the measured object (object) 10 and for the reception ultrasonic sensor 74 to receive a reflected wave. Distance measurement is performed based on Equation 1 using the measurement time.
Note that the CPU 7320 performs a correction process in cooperation with the distance measurement sensitivity correction circuit 734 in addition to the above-described distance measurement process. Further, the CPU 7320 can be shared with the control means 5 illustrated in FIG.

The crystal oscillation circuit 7321 includes a CPU 7320
Is a signal source of the clock CLK. Therefore,
When the CPU 7320 is shared with the control means 5, an existing crystal oscillator of a microcomputer in the control means 5 can be used as the crystal oscillation circuit 7321.

The ultrasonic distance measuring means 7 illustrated with reference to FIGS. 4 and 5 can accurately measure the distance to the measured object (object) 10. In particular, since the ultrasonic distance measuring means 7 corrects the sensitivity, the distance can be accurately measured without increasing the power applied to the ultrasonic sensor 73 for reception. In particular, the inventor of the present application has found that changing the pulse width of the carrier substantially changes the power of the transmitting ultrasonic sensor. Therefore, it is possible to substantially change the applied power of the transmitting ultrasonic sensor without using a power amplifier circuit as a variable amplifier circuit or the like. In the present invention, optimally set the pulse width of the carrier according to the distance,
The transmission ultrasonic sensor is driven by the power according to the pulse width.

Preferably, the pulse width of the carrier is set up to the object to be measured (object) 10, for example, at a distance in the middle of the measurement range, and the transmission ultrasonic sensor is driven by the carrier to roughly Perform distance measurement. Next, from the result of the approximate distance measurement, a pulse width of a carrier most suitable for the distance measurement is determined, and the transmission ultrasonic sensor is driven by the carrier having the pulse width to perform the distance measurement. This second distance measurement is an accurate distance measurement.

Although the above-described processing of the ultrasonic distance measuring means 7 has been described for the case where accurate distance measurement is performed, as described with reference to FIG. 4, the antenna 1 and the object to be measured (object ) It is also possible to measure the distance to 10. In that case, the antenna 76, the sensitivity correction circuit 724, and the antenna 75 illustrated in FIG. 5 are removed, and the processing of the CPU 7220 is simplified. Further, the receiving ultrasonic sensor 73 and the receiving horn antenna 74 may be one ultrasonic sensor for both transmission and reception.

Referring again to the circuit illustrated in FIG.
As described above, based on the result of measuring the distance between the antenna 1 and the measured object (object) 10 by the ultrasonic distance measuring means 7, the control means 5 determines the matching condition of the antenna matching circuit 3,
In the above-described example, a matching circuit according to the distance measurement result is selected, and impedance matching between the antenna 1 and the antenna matching circuit 3 is performed under optimal conditions. If transmission and reception are performed under such optimal impedance matching conditions, the mobile phone 30 can always talk in a good state.

The adjustment of the antenna matching circuit 3 by the control means 5 is performed by adjusting the antenna 1 and the object to be measured (object) 10.
It is preferable to perform this only when the distance from the object is within a predetermined range. The reason for this is that it is not normal to make a call when the distance between the measured object (object) 10 and the antenna 1 is longer than a predetermined distance, and that the measured object (object) 10 is very far from the antenna 1 This is because the influence on the antenna 1 is small.

In the above example, the case where the antenna 1 and the head of the human body as the object to be measured (object) 10 are located in the vicinity has been described, but the ultrasonic distance measuring means 7 measures the distance. The object to be performed is not limited to the head of the human body, but may be an object located near the antenna 1, for example, a metal object.

The adjustment of the matching condition of the antenna matching circuit 3 by the control means 5 can be performed not only in a stepwise manner by switching the switches described above but also continuously. In that case, the antenna matching circuit 3 is constituted by a variable resistance element, a variable capacitance element and the like, and the control means 5 changes the values of the variable resistance element and the variable capacitance element.

The antenna matching circuit 3 by the control means 5
Can be prevented from being performed, for example, by setting a mode switch in the mobile phone 30.

Note that the portable telephone 30 is shown in FIGS.
In the case where the ultrasonic distance measuring means 7 described with reference to FIG. 7 is mounted and operated, the mobile phone 30 itself is equipped with various electronic circuits and a power supply (battery) for operating the electronic circuits. There is no electrical problem in operating the means 7. Further, since the circuit configuration of the ultrasonic distance measuring means 7 is not particularly complicated and small,
Can be easily accommodated.

As described above, the embodiment of the present invention has been described with respect to a small portable communication device, particularly a portable telephone. However, the present invention can be applied not only to a portable telephone but also to a normal communication device. Will be easy to understand. For example, in a fixed communication device, an obstacle located near the antenna, in particular, a metal object that absorbs and reflects radio waves, and the position of the antenna are measured by the same method as the ultrasonic distance measuring means 7 described above. Then, by adjusting the matching condition of the antenna matching circuit 3 in the same manner as the control means 5 described above, optimal communication becomes possible.

Second Embodiment Referring to FIGS. 7 to 10, a small portable communication device will be described as a second embodiment of the communication device of the present invention. FIG. 7 is a circuit configuration diagram of the ultrasonic receiver 72A corresponding to FIG. 5, and FIGS. 8A to 8F explain the operation of the ultrasonic receiver 72A illustrated in FIG. 7 corresponding to FIG. It is a graph. Also in the second embodiment of the present invention, basically,
The configuration of the mobile phone illustrated in FIG. 1 is the same, and the control unit 5 and the ultrasonic distance measuring unit 7 in FIG. 1 are different from the first embodiment in the following points. Therefore, the configuration illustrated in FIGS. 1 to 3 and the basic configuration of the ultrasonic distance measuring means 7 illustrated in FIG. 4 are the same as those in the above-described first embodiment.

Hereinafter, differences from the first embodiment will be mainly described. In the first embodiment, the distance between the antenna 1 and the measured object (object) 10 is calculated from the reflected wave of the ultrasonic wave first received (detected) by the ultrasonic distance measuring means 7 and controlled. The circuit conditions of the matching circuit of the antenna matching circuit 3 were adjusted according to the distance calculated by the means 5. However, the one that changes the characteristics of the antenna 1 the most is not the one that is closest to the antenna 1. For example, when a reflected wave from a part of the hair or a part of the frame of the glasses is first detected, it is often the case that the characteristics of the antenna 1 are not significantly changed. Adjusting the antenna matching circuit 3 only by the distance may rather have an adverse effect. Thus, in the second embodiment, the largest factor that causes a change in the characteristics of the antenna 1 is detected, and the antenna matching circuit 3 is adjusted for that factor.

Therefore, the ultrasonic receiver 7 illustrated in FIG.
2A, the buffer circuit / comparison circuit 730A and the distance measurement calculation control circuit 732A are combined with the buffer circuit / comparison circuit 730 and the distance measurement calculation control circuit 732 illustrated in FIG.
And different. In the following, particularly, differences from the first embodiment will be mainly described.

FIG. 8 is a circuit diagram of a comparison circuit of the buffer circuit / comparison circuit 730A. Buffer circuit / comparison circuit 73
0A denotes a first comparison circuit CMP1 and a second comparison circuit C1.
MP2 and an inverter INV. As illustrated in FIG. 9E, the first comparison circuit CMP1 outputs the first high level “H” when the envelope detection signal S728 from the detection circuit 728 is at a level equal to or higher than the first reference voltage REF1. The comparison result CMP1 (O) is output. First comparison result C
MP1 (O) indicates that the reflected ultrasonic wave has reached the effective level and the rising timing. The envelope detection signal S728 from the detection circuit 728 is
The voltage is applied to the second comparison circuit CMP2 via NV, and is compared with the second reference voltage REF2. When the inverted envelope detection signal S728 from the detection circuit 728 is at a level equal to or higher than the second reference voltage REF2, the second comparison circuit CMP2 outputs a high-level “H” first comparison result CMP2.
(O) is output. The second comparison result CMP2 (O) is
This shows that the reflected ultrasonic wave has fallen and the fall timing.

The operation of the ultrasonic receiver 72A relating to FIGS. 9A to 9D is the same as that of the first embodiment.

The arithmetic control processing unit (CPU) 7320A in the distance measurement arithmetic control circuit 732A includes a first comparison result CM output from the buffer circuit / comparison circuit 730A.
P1 (O) and the second comparison result CMP2 (O) are input, and the time (time difference) t from the rise to the fall of the reflected ultrasonic wave is calculated.

The calculation of the time t can be performed by the buffer circuit / comparison circuit 730A. The timing is performed, for example, using the counter CNTR illustrated in FIG. A clock CLK of a predetermined frequency is applied to the counter CNTR. The counter CNTR resets the count value with a clear signal CLR, starts counting the clock CLK with a pulse applied to the start terminal STR, and stops at the stop STP. The counting is stopped by the applied pulse. The first comparison result CMP1 is connected to the start terminal STR.
(O) is applied to start counting, and the second
When the counting is stopped by applying the comparison result CMP2 (O), the counter CNTR sets the first comparison result CMP1 (O)
Are applied and the clock CLK from when the second comparison result CMP2 (O) is applied is counted. This count value corresponds to time t.

The time T can be counted by either the CPU 7320A or the buffer circuit / comparison circuit 730A.
In the latter case, the processing load on the CPU 7320A is reduced, and an accurate time T can be detected.

As in the first embodiment, the CPU 7320A outputs the first comparison result CMP1 of high level “H”.
The distance L is calculated based on Equation 1 with reference to (O).

The ultrasonic receiver 72A emits an ultrasonic wave from the transmitting ultrasonic sensor 73 to a range for calculating the distance between the antenna 1 and the measured object (object) 10, for example, a range of 50 cm. During the time during which the reflected ultrasonic wave can be received by the receiving ultrasonic sensor 74, each time the reflected ultrasonic wave is received by the receiving ultrasonic sensor 74, the above-described measurement of the time T and the calculation of the distance are performed. That is, the transmission ultrasonic sensor 73
When an ultrasonic wave is radiated from a plurality of obstacles (measured objects (objects) 10), the ultrasonic wave is
As illustrated in FIG. In the first embodiment, a detectable reflected ultrasonic wave is detected during a receivable time. Note that the waveform diagram of FIG.
This corresponds to the waveform diagram of FIG.

The control means 5 determines the time difference (time) t between the rising timing and the falling timing for the reflected ultrasonic wave calculated by the CPU 7320A.
And the distance L are input from the transmitting ultrasonic sensor 73A (ultrasonic distance measuring means 7), and among these reflected ultrasonic waves, the one that most affects the characteristics of the antenna 1 is estimated. The estimation method will be described with reference to FIG. As described above, since the CPU 7320A and the control means 5 can be integrated, the CPU 7320A and the control means 5 can be integrated.
Is integrated, the following processing is performed in the integrated CPU 7320A or the control means 5.

A priority coefficient P is defined in the order of the reflected ultrasonic waves. In this example, it is determined as follows. (1) The priority coefficient P1 of the first detected reflected ultrasonic wave =
1.0 (2) Priority coefficient P2 of the second detected reflected ultrasonic wave
= 0.5 (3) The priority coefficient P3 of the third detected reflected ultrasonic wave
= 0.25 (4) The priority coefficient P4 of the fourth detected reflected ultrasonic wave
= 0.25

The priority coefficient P is set higher as the distance from the antenna 1 becomes shorter and the reflected ultrasonic wave returns earlier.

Considering the priority coefficient P,
The larger the distance between the antenna 1 and the measured object (object) 10 is, the more the measured object (object) 10 given to the antenna 1 is.
Is inversely proportional (or inversely proportional to the square of the distance), the control means 5 determines the priority coefficient P according to the detection time of the first comparison result CMP1 (O) instead of the arrival order described above.
In each case, the weighting coefficient can be determined. For example, the first arrived first comparison result CMP1
The priority coefficient P1 of (O) is set to 1.0, and the priority coefficient Pn of the first comparison result CMP1 (O) that has arrived last is Pn = 1.0.
As 0.1, a value between 1.0 and 0.1 is set as the priority coefficient P corresponding to the second and subsequent comparison result detection times. As this association, various methods such as a method of making the detection time inversely proportional and a method of making the detection time 1/2 power can be adopted.

Next, the control means 5 performs the following calculation for each reflected ultrasonic wave.

Di = (ti / Li) × Pi (2) where Di is a determinant of the i-th reflected ultrasonic wave,
ti is the time of the i-th reflected ultrasonic wave, Li is the measured distance of the i-th reflected ultrasonic wave, and Pi is the priority coefficient of the i-th reflected ultrasonic wave.

(Ti / Li) in the equation 2 is a value for estimating the magnitude of the waveform of the reflected ultrasonic wave. The control means 5
The result of multiplying (ti / Li) by the priority coefficient Pi is compared in magnitude. The control means 5 estimates the largest one of the judgment factors Di as the object to be measured (object) which most affected the antenna 1. Then, the control means 5 changes the matching circuit condition of the antenna matching circuit 3 according to the magnitude of the determination factor D.

As the method, the judgment factor D is set to 0 to 1.
0, the horizontal axis plots the judgment factor D, the vertical axis plots the matching circuit conditions, and stores the results in a memory such as a ROM. The corresponding matching condition is read out, and the antenna matching circuit 3 is adjusted as in the first embodiment.

As described above, according to the second embodiment, unlike the first embodiment, the antenna matching circuit 3 is not adjusted merely depending on the distance of the first reflected ultrasonic wave. Since the antenna matching circuit 3 is adjusted for the one that substantially affects the characteristics of the antenna 1, more accurate adjustment is possible.

Third Embodiment A third embodiment of the present invention will be described. In the third embodiment of the present invention, instead of (ti × Li) in equation (2),
The envelope detection circuit 728 of FIG. 7 integrates the envelope detection result for the reflected ultrasonic wave, and determines whether the integration result S exceeds a predetermined level in the buffer circuit / comparison circuit 730 and is an effective reflected ultrasonic wave. In the case of an effective reflected ultrasonic wave, the control unit 5 performs the following calculation.

Di = (Si / Li) × Pi (3) where Di is a determinant of the i-th reflected ultrasonic wave,
Si is an i-th envelope detection integration result, Li is a measurement distance of the i-th reflected ultrasonic wave, and Pi is a priority coefficient of the i-th reflected ultrasonic wave.

The control means 5 is similar to the second embodiment,
The largest one of the judgment factors Di is estimated to be the object to be measured (object) that most affected the antenna 1. Then, the control means 5 changes the matching circuit condition of the antenna matching circuit 3 according to the magnitude of the determination factor D.

As in the second embodiment, as in the second embodiment, the judgment factor D is normalized between 0 and 1.0, the horizontal axis is the judgment factor D, and the vertical axis is the matching circuit condition. The result is stored in a memory such as a ROM, and the control unit 5 reads out the matching condition according to the determination factor D by a table lookup method, and adjusts the antenna matching circuit 3 as in the first embodiment.

As described above, according to the third embodiment, similarly to the second embodiment, the antenna matching circuit 3 is adjusted to the one that substantially affects the characteristics of the antenna 1 substantially. More accurate adjustment is possible.

[0078]

According to the present invention, the influence on the human body is small,
Low cost, small size, stable operation for a long period of time, for example, has a distance measuring means that can be mounted on a small communication device such as a mobile phone, and has the greatest influence on the distance measured by the distance measuring means and the antenna And a communication device capable of adjusting the circuit conditions based on the estimation of the object that gives the following.

Further, according to the present invention, a small portable communication device having a distance measuring means can be provided.

[Brief description of the drawings]

FIG. 1 is a partial configuration diagram of a small portable communication device as an embodiment of a communication device of the present invention.

FIG. 2 is a diagram illustrating a positional relationship between a mobile phone as an embodiment of the present invention and a head of a human body as an object to be measured (object).

FIG. 3 is a graph illustrating that the power absorption changes in FIG. 2 depending on the distance between the antenna of the mobile phone and the head of the human body.

FIG. 4 is a schematic configuration diagram of an ultrasonic distance measuring unit illustrated in FIG. 1 mounted on a mobile phone.

FIG. 5 is a detailed circuit configuration diagram of a first embodiment of the ultrasonic distance measuring means illustrated in FIG. 4;

6 (a) to 6 (e) are signal waveform diagrams for explaining the operation of the ultrasonic distance measuring means illustrated in FIGS. 4 and 5. FIG.

FIG. 7 is a detailed circuit configuration diagram of a second embodiment and a third embodiment of the ultrasonic distance measuring means illustrated in FIG. 4;

8 is a diagram illustrating an example of a circuit configuration of a buffer circuit / comparing circuit in the ultrasonic distance measuring unit illustrated in FIG. 7;

9 (a) to 9 (f) are signal waveform diagrams for explaining the operation of the ultrasonic distance measuring means illustrated in FIG. 7;

FIG. 10 is a signal waveform diagram illustrating a processing method according to the second embodiment and the third embodiment.

[Explanation of symbols]

 1. Antenna 3. Antenna matching circuit 5. Control means 7. Ultrasonic distance measuring means 71 Ultrasonic transmitter 72, 72A Ultrasonic receiver 73 Ultrasonic sensor for reception 74 Ultrasonic sensor for reception 75, horn antenna for transmission 76, horn antenna for reception 10, object to be measured (object) 30, mobile phone

Claims (8)

[Claims] An antenna, a matching circuit for impedance matching with the antenna, a distance between the antenna and an object is measured by ultrasonic waves, a size of the object is estimated, the measured distance, the estimated object Is multiplied by a priority coefficient based on the order of reception of the reflected ultrasonic waves to calculate an evaluation value that affects the antenna characteristics, and adjusts the matching circuit conditions of the matching circuit according to the evaluation value. A communication device having circuit condition adjusting means. 2. The transmitting apparatus according to claim 1, wherein said circuit condition adjusting means estimates the size of said object from a time difference between a rise time and a fall time of said ultrasonic reflected wave and said measured distance. 3. The transmitting apparatus according to claim 1, wherein said circuit condition adjusting means estimates a size of said object from an integration result of an envelope detection signal of said ultrasonic reflected wave and said measured distance. 4. The circuit adjusting means includes a distance measuring means and a matching condition adjusting means, wherein the distance measuring means is provided in the transmitting ultrasonic sensor provided in the communication device, and in the communication device. An ultrasonic sensor for reception, an excitation unit that excites the ultrasonic sensor for transmission provided in the communication device, and an ultrasonic wave radiated from the ultrasonic sensor for transmission provided in the communication device. The ultrasonic wave reflected by the object is received by the ultrasonic sensor for reception, the time from transmission of ultrasonic wave to reception of ultrasonic wave is measured, and the ultrasonic sensor for transmission or the reception is measured from the measurement time. Ultrasonic distance measuring means for measuring the distance from the ultrasonic sensor for the object to the object, the matching condition adjusting means, the measured distance, the estimated object size, and the ultrasonic reflected wave In the receiving order Multiplied by the brute priority coefficient, calculates an evaluation value that affects the antenna characteristics, to adjust the matching circuit condition of the matching circuit in accordance with the evaluation value, claim 2 having a computer
The communication device as described. 5. The circuit adjusting means has a distance measuring means and a matching condition adjusting means, wherein the distance measuring means is provided in the transmitting ultrasonic sensor provided in the communication device, and in the communication device. An ultrasonic sensor for reception, an excitation unit that excites the ultrasonic sensor for transmission provided in the communication device, and an ultrasonic wave radiated from the ultrasonic sensor for transmission provided in the communication device. The ultrasonic wave reflected by the object is received by the ultrasonic sensor for reception, the time from transmission of ultrasonic wave to reception of ultrasonic wave is measured, and the ultrasonic sensor for transmission or the reception is measured from the measurement time. Ultrasonic distance measuring means for measuring the distance from the ultrasonic sensor for the object to the object, the matching condition adjusting means, the measured distance, the estimated object size, and the ultrasonic reflected wave In the receiving order Multiplied by the brute priority coefficient, calculates an evaluation value that affects the antenna characteristics, to adjust the matching circuit condition of the matching circuit in accordance with the evaluation value, claim 3 having a computer
The communication device as described. 6. The communication device according to claim 4, wherein said communication device is a small portable communication device. 7. An ultrasonic sensor for transmission, an ultrasonic sensor for reception, excitation means for exciting the ultrasonic sensor for transmission, and an ultrasonic wave emitted from the ultrasonic sensor for transmission is reflected by an object, The reflected ultrasonic wave is received by the ultrasonic sensor for reception, the time from transmission of the ultrasonic wave to reception of the ultrasonic wave is measured, and the ultrasonic wave sensor for transmission or the ultrasonic sensor for reception is measured from the measurement time. Ultrasonic distance measuring means for measuring the distance to the object, Estimating the size of the object, the measured distance, the estimated object size, and priority based on the receiving order of the ultrasonic reflected wave A compact portable communication device comprising: a circuit condition adjusting unit that calculates an evaluation value that affects antenna characteristics by multiplying a coefficient and adjusts a matching circuit condition of a matching circuit according to the evaluation value. 8. The small portable communication device according to claim 7, wherein said transmitting ultrasonic sensor and said receiving ultrasonic sensor are integrally formed.