JP2006148948A - Wireless microphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless antenna device capable of preventing obstacles from interfering or damaging and securing a high antenna gain. <P>SOLUTION: The device is comprised to mount a flat antenna array 1 on a video camera 4 by fixing the flat antenna array 1 faced in front of the video camera 4 through a connector 3 on a receiving device 2. Thereby, antenna height at an upper part of the video camera 4 is suppressed, and directivity of the flat antenna 1 is faced in front of the video camera 4 so as to secure a directivity gain of the antenna. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless microphone device and a wireless antenna device of a wireless receiving device equipped in a video camera.

  2. Description of the Related Art Conventionally, an antenna configuration of a wireless microphone receiving apparatus that is connected to a video camera and receives a transmission signal from a wireless microphone apparatus is, for example, a flip type antenna as disclosed in Japanese Utility Model Publication No. 62-53867. Paul was generally used.

  As another conventional example, a configuration in which a monopole antenna or a sleeve antenna as shown in FIG. 7 is fixed to the upper part of the video camera has been used. That is, in FIG. 7, 2 is a receiving device that demodulates the received audio signal, 4 is a video camera that captures the subject, and 5 is a wireless microphone transmitter that is fixed to the upper portion of the receiving device 2 and carried by the subject. 3 is a connector part for connecting the sleeve antenna part 5 to the receiving device 2. In general, the wireless antenna of this type of wireless microphone device uses an 800 MHz band (wavelength of about 380 mm), and the height of the sleeve antenna portion 5 protruding above the video camera 4 is usually 2 minutes. About one wavelength (about 190 mm).

  The video camera 4 is a portable imaging / recording device, and is generally taken by a photographer with his / her shoulder on his / her body. The receiving device 2 is a wireless receiving device built in the video camera 4. In general, the receiving device 2 receives radio waves from a wireless microphone transmitter carried by a subject such as a person and inputs the demodulated audio signal to the video camera 4. . The video camera 4 records the audio signal input from the receiving device 2 together with the image. The sleeve antenna unit 5 is electrically connected to the receiving device 2 via the connector unit 3 and is mechanically fixed.

  In addition, since the directivity in the horizontal plane of the sleeve antenna is omnidirectional, in this conventional example, the directivity of the antenna of the receiving apparatus is all in spite of the fact that the wireless microphone transmitter is always in front of the video camera 4. Will be directed. In this case, the gain of the sleeve antenna is generally about 2.1 dBi.

  As a built-in antenna of a conventional wireless microphone transmitter, for example, an antenna configured by arranging a monopole antenna or a dipole antenna inside a wireless microphone casing has been used. Another example of the antenna with a built-in wireless microphone is an inverted L antenna disposed inside a wireless microphone casing (as disclosed in Japanese Patent Laid-Open No. 9-98494) as shown in FIG. It has been known.

That is, in FIG. 8, a lead wire 4 is connected to the antenna element 1, a power feeding connector 5 is connected to a predetermined position of the printed circuit board 2, and the antenna element 1 and the printed circuit board 2 are arranged in parallel. Thus, an inverted L-type antenna structure is configured. In addition, the parasitic element 3 for impedance matching is disposed so as to face the antenna element 1 and the distance 6 between the antenna element 1 and the parasitic element 3 for impedance matching is changed so that the impedance matching is optimal. I try to let them.
Japanese Utility Model Publication No. 62-053867

  Among the wireless antenna devices according to the conventional examples as described above, regarding the configuration of the wireless antenna device of the wireless microphone receiving device connected to the video camera, the height of the wireless antenna protruding on the upper part of the video camera is a half wavelength. Since it is relatively long (about 190 mm), there is a problem that it is easy to come in contact with an obstacle during photographing work and there are many failures due to breakage.

  Further, in the configuration of the conventional wireless antenna device used for the video camera as described above, the directivity of the wireless antenna becomes almost omnidirectional in the horizontal plane, and therefore, generally, the direction in which the video camera is facing (human or the like). There is a problem that the antenna gain in the front direction of the video camera that is the subject of shooting or the direction of the subject cannot be increased.

  Among the wireless antenna devices according to the conventional examples as described above, in the wireless antenna device built in the wireless microphone transmitter, the gain of the wireless antenna deteriorates due to the proximity effect of the hand depending on the position of the hand holding the wireless microphone. There was a problem that the degree to do changes greatly. For example, when a wireless microphone having a wireless antenna disposed at the lower part is gripped by the hand, the deterioration of the wireless antenna gain is large, and generally a deterioration of about 10 to 15 dB occurs. On the other hand, when the upper part of the wireless microphone, that is, the vicinity of the microphone without the wireless antenna is gripped, there is almost no deterioration of the wireless antenna gain.

  The present invention has been made to solve the above-described conventional problems. The height of the wireless antenna protruding from the upper part of the video camera is reduced to prevent breakage, and the directivity of the wireless antenna is set in front of the video camera. An object of the present invention is to provide a wireless antenna device of a wireless reception device installed in a video camera that secures a high antenna gain.

  Another object of the present invention is to provide a wireless antenna device equipped in a wireless microphone device (wireless microphone transmitter) that can ensure a high antenna gain regardless of the position of the wireless microphone device held by the hand. .

  The present invention automatically selects and switches the wireless antenna (the first antenna or the second antenna) where the wireless microphone is not held by the hand, regardless of where the hand is held by the hand. A wireless microphone that can be secured is obtained.

(Embodiment of the Invention)
According to a first aspect of the present invention, there is provided a first antenna disposed at a lower portion of a wireless microphone, a second antenna disposed in the vicinity of the microphone unit at a certain distance from the first antenna, and the microphone unit. A transmission circuit that processes a voice transmission signal from the transmitter and outputs a high-frequency transmission signal; a high-frequency signal switching circuit that switches the high-frequency transmission signal from the transmission circuit to either the first antenna or the second antenna; and the high-frequency signal A directional coupler that is inserted between the switching circuit and the transmission circuit and detects a reflection component of the high-frequency transmission signal from the first antenna and the second antenna, and receives a detection result of the reflection component by the directional coupler. Detection control for switching the high-frequency signal switching circuit so as to connect the high-frequency transmission signal from the transmission circuit to the antenna having the smaller reflection component. A high-frequency transmission signal from the transmission circuit is automatically converted to the antenna having the smaller reflection component by selecting the antenna having the smaller reflection component from the first antenna or the second antenna by the detection control unit. To switch to send,
Regardless of the position held by the hand of the wireless microphone device, a high antenna gain can be secured.

According to a second aspect of the present invention, there is provided a first antenna disposed in a lower portion of a wireless microphone, a second antenna disposed in the vicinity of the microphone unit at a certain distance from the first antenna, and the microphone unit. A transmission circuit for processing and outputting a voice transmission signal from the circulator, and a circulator for transmitting a high-frequency transmission signal from the transmission circuit to the first antenna and transmitting a reflected signal from the first antenna to the second antenna, An antenna that automatically transmits a high-frequency transmission signal from a transmission circuit for transmission to the first antenna and transmits it to the second antenna via a circulator when there is a reflected signal from the first antenna. It ’s what you choose,
This simplifies the configuration of the antenna selection circuit, reduces the size of the entire device, and ensures high antenna gain regardless of the position held by the hand of the wireless microphone device.

Invention of Claim 3 of this invention comprises the said 1st antenna with a helical antenna, and comprised the 2nd antenna with the loop antenna,
It has an effect that a space-saving built-in antenna adapted to the upper and lower shapes of the wireless microphone can be configured.

  According to the present invention, two wireless antenna devices are provided in a wireless microphone transmitter, and an antenna having a good impedance matching state is automatically selected according to the level of a reflected signal from the antenna. It is possible to provide a wireless microphone that can ensure transmission and transmit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and FIGS. FIG. 1 is a basic conceptual diagram of a video camera equipped with a wireless antenna device according to a first embodiment of the present invention, and FIG. 2 is a basic concept of a wireless antenna device equipped in a video camera according to a second embodiment of the present invention. FIG. 3 is an explanatory diagram of the operation of the wireless antenna device according to the second embodiment of the present invention, and FIG. 4 is a basic conceptual diagram of a video camera equipped with the wireless antenna device according to the third embodiment of the present invention. FIG. 5 is a diagram showing a configuration of a wireless microphone transmitter according to a fourth embodiment of the present invention, (A) is a diagram showing a configuration of a wireless antenna device built in the wireless microphone transmitter, and (B) is a wireless diagram. FIG. 6C shows a state where the lower part of the microphone is held by hand, FIG. 6C shows a state where the upper part of the wireless microphone is held by hand, and FIG. In the fifth embodiment of the invention is a diagram showing a configuration of a wireless antenna device incorporated in a wireless microphone transmitter.
(First embodiment)
First, with reference to FIG. 1, the configuration of a wireless antenna device equipped in a video camera according to the first embodiment of the present invention will be described. In FIG. 1, 2 is a receiver for demodulating a received audio signal, 4 is a video camera for photographing a subject, 1 is fixed to the upper part of the receiver 2, and a wireless microphone transmitter 17 carried by the subject (see FIG. 1). A planar antenna unit 3 for receiving radio waves from 5) is a connector unit for connecting the planar antenna unit 1 to the receiving device 2.

  Next, with reference to FIG. 1, the operation of the wireless antenna device equipped in the video camera in the present embodiment will be described. The video camera 4 is a portable imaging / recording device. In general, a photographer carries a picture on the shoulder while holding the body facing the subject. The receiving device 2 is a wireless receiving device built in the video camera 4. Generally, the receiving device 2 receives radio waves from a wireless microphone transmitter 17 carried by a subject such as a person, and converts the demodulated audio signal into the video camera 4. To enter. The video camera 4 records the audio signal input from the receiving device 2 together with the image. The planar antenna unit 1 is electrically connected to the receiving device 2 through the connector unit 3 and is mechanically fixed by the connector unit 3.

  The planar antenna unit 1 is disposed in front of the video camera 4 so that the antenna element surface of the planar antenna unit 1 is directly opposed, and is generally configured by a plate-like inverted F antenna formed on a dielectric substrate. . In a plate-like inverted F antenna formed on a dielectric substrate, it is known that the perimeter of the antenna element resonates at λg / 2 (λg is the wavelength on the dielectric substrate). For example, when the relative dielectric constant of the dielectric substrate is selected to be about 3.6 in the 800 MHz band, the length of one side of the antenna element, that is, the height of protrusion on the upper part of the video camera 4 is about 24 mm.

  In addition, since the antenna element (plate-shaped inverted F antenna) of the planar antenna unit 1 is arranged so as to face the front of the video camera 4, the directivity of the planar antenna is directed to the front of the video camera 4. . Since the video camera 4 is always directed toward the subject (person or the like), the directivity of the planar antenna can be directed toward the wireless microphone transmitter 17 carried by the subject (person or the like). In this case, the directivity gain in the maximum gain direction of the planar antenna can generally be about 3 to 4 dBi.

  As described above, since the directivity in the horizontal plane of the sleeve antenna 5 in the above-described conventional example is omnidirectional, the sleeve antenna of the receiving device 2 is provided even though the wireless microphone transmitter 17 is always in front of the video camera 4. The directivity of 5 is directed in all directions. In this case, the gain of the sleeve antenna 5 is generally about 2.1 dBi.

As described above, according to the first embodiment of the present invention, the height of the planar antenna unit 1 protruding from the upper part of the video camera is about 1/7 of the sleeve antenna 5 in the conventional example. Therefore, the problem of interfering with obstacles can be avoided. Further, since the antenna directivity of the receiving device 2 connected to the video camera 4 can always be directed toward the wireless microphone transmitter 17, the directivity gain is about 3 to 4 dBi, which is about 2. A directivity gain considerably higher than 1 dBi can be obtained.
(Second Embodiment)
Hereinafter, with reference to FIG. 2, a configuration of a wireless antenna device equipped in a video camera according to a second embodiment of the present invention will be described. In FIG. 2, 31 is a planar antenna unit that includes a plurality of planar antenna elements 8a to 8d and is fixed to the upper part of the receiving apparatus 2 and receives radio waves from the wireless microphone transmitter 17 (FIG. 5) carried by the subject. Reference numerals 8a to 8d denote a plurality of planar antenna elements constituting the planar antenna unit 31, and 6 denotes a dielectric substrate in which a plurality of planar antenna elements 8a to 8d are formed on the surface by etching, plating, pasting or other means.

  Reference numeral 7 denotes a ground plate on which the dielectric substrate 6 is mounted to be a ground for the planar antenna elements 8a to 8d, and 9a to 9d are ground contacts provided to the planar antenna elements 8a to 8d. Through-holes 10a and 10b become power distributors that synthesize received signals from the planar antenna elements 8a to 8d and output them to the receiving device 2, and 11a and 11b connector portions that connect the planar antenna unit 31 to the receiving device 2. It is. The video camera 4 and the receiving device 2 are the same as those shown in FIG.

  Next, with reference to FIG. 3, the operation of the wireless antenna device equipped in the video camera according to the second embodiment will be described. In FIG. 3, the dielectric substrate 6 is generally composed of a dielectric substrate having a plate thickness of about 5 mm to 8 mm and a relative dielectric constant of about 2 to 4 (but may be of any other size). The dielectric substrate 6 is mounted on the ground plate 7, and the ground plate 7 operates as a ground plane for the planar antenna elements 8 a to 8 d configured on the dielectric substrate 6. The ground plate 7 is connected to the ground side of the connector portions 11 a and 11 b and operates as a ground plane for the entire planar antenna portion 31. Each of the planar antenna elements 8a to 8d constitutes a plate-like inverted F antenna. The through holes 9a to 9d operate as ground contacts for the plate-like inverted F antennas formed by the planar antenna elements 8a to 8d, respectively.

  Further, the power distributors 10a and 10b are configured on the dielectric substrate 6 by microstrip lines. Received signals from the planar antenna elements 8a and 8b are combined by the power distributor 10a and guided to the connector portion 11a. Received signals from the planar antenna elements 8c and 8d are combined by the power distributor 10b and guided to the connector portion 11a. As described above, the planar antenna elements 8a and 8b and the planar antenna elements 8c and 8d constitute two sets of antenna arrays. By configuring the antenna array with the planar antenna elements 8a, 8b, 8c, and 8d, the directivity of each planar antenna element 8a, 8b, 8c, and 8d is synthesized, and high directivity gain in the front direction. Can be obtained.

  In this case, generally, a directivity gain of about 5 to 6 dBi can be obtained in the maximum gain direction. Further, a space diversity antenna is configured by configuring two sets (8a and 8b and 8c and 8d) of antenna arrays. Here, the height of the planar antenna unit 31 in the 800 MHz band is obtained by adding the length of one side (about 24 mm) of the planar antenna elements 8a to 8d and the length of the power distributors 10a to 10b (about 15 mm). The length can be made substantially equal to the length of about 40 mm.

  Next, with reference to FIG. 3, the horizontal plane directivity of the wireless antenna device equipped in the video camera according to the second embodiment will be described. In FIG. 3, 1 is a planar antenna unit in the present embodiment, 4 is a video camera equipped with a planar antenna unit 31, 12 is a photographer who points the video camera 4 toward the subject 15, and 13 is a plane in the present embodiment. The directivity pattern of the antenna unit 31, 14 indicates the antenna directivity pattern according to the conventional example, and 15 indicates a subject that emits sound to the wireless microphone. In FIG. 3, the video camera 4 is held on the shoulder of the photographer 12 and is directed toward the subject 15.

  In the second embodiment of the present invention, the planar antenna unit 31 is directed toward the front of the video camera 4, and the directivity pattern 13 is as shown in FIG. The directivity gain with respect to the maximum gain direction (subject direction) is about 5 to 6 dBi. On the other hand, since the directivity in the horizontal plane of the sleeve antenna 5 according to the conventional example shown in FIG. 2 is omnidirectional, the directivity pattern 14 becomes a circular directivity pattern as shown in FIG. Is approximately 2.1 dBi.

That is, as described above, according to the planar antenna unit of the present embodiment, by configuring the antenna array, the directivity gain is about 5 to about 2.0 dBi compared to about 2.1 dBi of the directivity gain of the conventional sleeve antenna. A considerably high result of 6 dBi can be obtained.
(Third embodiment)
Hereinafter, with reference to FIG. 4, the configuration of a wireless antenna device equipped in a video camera according to a third embodiment of the present invention will be described. The wireless antenna device according to the present embodiment is configured such that a planar antenna unit 41 as shown in FIG. In FIG. 4, 2 is a receiver for demodulating a received audio signal, 4 is a video camera for photographing a subject, and 41 is a wireless microphone transmitter 17 that is fixed to the front of the video camera 4 and carried by the subject (FIG. 5). ) Is a planar antenna unit for receiving radio waves from 16), and 16 is a connection cable for connecting the planar antenna unit 41 to the receiving device 2.

  In FIG. 4, since the planar antenna unit 41 is arranged in front of the video camera 4, there is no interference such as a handle or a photographer's head in the direction of the subject. Therefore, the planar antenna unit 41 of the first embodiment shown in FIG. A higher antenna gain can be ensured compared to the above.

The configuration and mounting position of the planar antenna units 1, 31, and 41 described above are not limited to the above-described configuration, and any other configuration and mounting position can be used as long as the configuration and mounting position provide the same directivity gain. The mounting position may be sufficient, and the same effect can be obtained by this.
(Fourth embodiment)
Hereinafter, the configuration of the wireless antenna device built in the wireless microphone according to the fourth embodiment of the present invention will be described with reference to FIGS. 5A to 5C, reference numeral 17 denotes a wireless microphone transmission that converts an audio signal received from the microphone unit 26 into a high-frequency transmission signal and transmits the high-frequency transmission signal via the dielectric helical antenna 18 and the loop antenna 20. , 18 is a dielectric helical antenna (first antenna) arranged on a dielectric and disposed below the wireless microphone, and 19 transmits a high-frequency transmission signal to be transmitted from the high-frequency signal switching circuit 22 to the dielectric helical antenna 18. It is a transmission line.

  Reference numeral 20 denotes a loop antenna (second antenna) disposed above the wireless microphone. Reference numeral 21 denotes a transmission line for transmitting a high-frequency transmission signal to be transmitted from the high-frequency signal switching circuit 22 to the loop antenna 20. Reference numeral 22 denotes a transmission line from the transmission circuit 24. A high-frequency signal switching circuit that selectively switches the high-frequency transmission signal to the helical antenna 18 or the loop antenna 20, 23 is a directional coupler that guides the reflected signal from the helical antenna 18 or the loop antenna 20 to the detection control unit 25, and 24 is a microphone. A transmission circuit that modulates the audio electrical signal from the unit 26 and outputs a high-frequency transmission signal, 25 detects a reflection signal from the helical antenna 18 or the loop antenna 20 and switches the high-frequency signal switching circuit 22 to reflect the high-frequency transmission signal as a reflection signal Transmit from the antennas 18 and 20 with the smaller number Controller output, 26 microphone unit for converting the electric voice signal receiving sound, 27 is a hand of the human body or the like.

  That is, in FIG. 5A, the dielectric helical antenna 18 is configured as a dielectric-structured helical antenna (dielectric chip antenna), on the opposite side (lower side) of the microphone unit 26 inside the wireless microphone transmitter 17. Be placed. The dielectric helical antenna 18 is electrically connected to one switching terminal of the high-frequency signal switching circuit 22 via the transmission line 19. The loop antenna 20 is composed of a wire such as copper or a metal plate (strip), and is configured to surround the casing of the wireless microphone transmitter 17 on the microphone unit 26 side (upper side). The loop antenna 20 is electrically connected to the other switching terminal of the high-frequency signal switching circuit 22 via the transmission line 21.

  Next, the operation of the wireless antenna device built in the wireless microphone according to the fourth embodiment of the present invention will be described with reference to FIGS. The transmission circuit 24 modulates the audio electrical signal received from the microphone unit 26 and outputs a high-frequency transmission signal. The transmission signal is guided to the high-frequency signal switching circuit 22 via the directional coupler 23. Here, the directional coupler 23 operates so as to transmit a transmission signal traveling from the transmission circuit 24 to the antenna side with almost no loss, while guiding a reflected signal from the antenna side to the detection control unit 25.

  The detection control unit 25 can detect the level (return loss) of the reflected signal from the dielectric helical antenna 18 or the loop antenna 20 according to the connection state in the high-frequency signal switching circuit 22. For example, when the dielectric helical antenna 18 or the loop antenna 20 is covered with a hand or the like, the level of the reflected signal from the antenna 18 or 20 that is covered with the hand or the like increases. When the detection control unit 25 detects the reflected signal, the detection control unit 25 instructs the high-frequency signal switching circuit 22 to switch the currently connected antennas 18 and 20 to the other antennas 20 and 18. Therefore, the high-frequency transmission signal from the transmission circuit 24 passes through the terminal of the switched high-frequency signal switching circuit 22 and radiates the radio wave of the high-frequency transmission signal from the dielectric helical antenna 18 or the loop antenna 20 that is not covered by hands or the like. To do.

    That is, the detection control unit 25 is not covered by a hand or the like of the dielectric helical antenna 18 and the loop antenna 20 and can know the antenna with the better impedance matching state, and the impedance matching state is always good. Can be controlled to transmit through the other antenna.

  Next, with reference to FIGS. 5B and 5C, the operation of the microphone transmitter 17 in a state where the microphone transmitter 17 is held by the hand (human body) 27 will be described. 5B shows the case where the lower part of the wireless microphone transmitter 17 (opposite side of the microphone part 26) is held with the hand 27, and FIG. 5C shows the upper part (near the microphone part 26) with the hand 27. It shows the case of having it. In the case of FIG. 5B, since the periphery of the dielectric helical antenna 18 is covered with the hand 27, the impedance of the dielectric helical antenna 18 fluctuates and the antenna gain also deteriorates due to the proximity effect of the hand. . In this case, the detection control unit 25 detects that the impedance matching state of the dielectric helical antenna 18 is poor, and automatically switches the high-frequency signal switching circuit 22 to select the loop antenna 20 and transmit from there. On the other hand, in the case of FIG. 5C, the detection control unit 25 detects that the impedance matching state of the loop antenna 20 is bad, and selects the dielectric helical antenna 18 to transmit the high frequency signal switching circuit 22. To switch automatically.

As described above, according to the fourth embodiment of the present invention, the antenna on the side not affected by the hand having the wireless microphone transmitter can be automatically selected and transmitted. Gain can be secured.
(Fifth embodiment)
Hereinafter, with reference to FIG. 6, the configuration of the wireless antenna device built in the wireless microphone according to the fifth embodiment of the present invention will be described. In FIG. 6, reference numeral 17 denotes a wireless microphone transmitter that converts the audio signal received from the microphone unit 26 into a high-frequency transmission signal and transmits the high-frequency transmission signal via the dielectric helical antenna 18 and the loop antenna 20. A dielectric helical antenna (first antenna) 19 disposed below the microphone is a transmission line for transmitting a high-frequency transmission signal to be transmitted from the circulator 28 to the dielectric helical antenna 18.

  Reference numeral 20 denotes a loop antenna (second antenna) disposed above the wireless microphone, 21 denotes a transmission line for transmitting a high-frequency transmission signal to be transmitted from the circulator 28 to the loop antenna 20, and 24 denotes an audio electric signal from the microphone unit 26. 26 is a microphone unit that receives sound and converts it into an electrical signal, and 28 transmits the transmission signal from the transmission circuit 24 to the dielectric helical antenna 18. When there is a reflected signal from 18, the circulator transmits the reflected signal to the loop antenna 20.

  Next, the operation of the wireless antenna device built in the wireless microphone according to the fifth embodiment of the present invention will be described with reference to FIG. For example, as shown in FIG. 5B, when the lower part of the wireless microphone transmitter 17 is held by the hand 27, the impedance matching state of the dielectric helical antenna 18 is deteriorated, so that the high-frequency transmission signal is converted to the dielectric helical. The light is reflected by the antenna 18 and transmitted to the loop antenna 20 through the circulator 28. Further, as shown in FIG. 5C, when the upper part of the wireless microphone transmitter 17 is held by the hand 27, the impedance matching state of the dielectric helical antenna 18 is good, so that the transmission signal is the dielectric helical antenna 18 Is not transmitted to the loop antenna 20 because there is no reflection.

  As described above, according to the fifth embodiment of the present invention, the antenna on the side not affected by the hand having the wireless microphone transmitter can be automatically selected and transmitted. Gain can be secured.

  The present invention is configured as described above, and in particular, by using a planar antenna portion, the height of the antenna protruding on the upper part of the video camera can be suppressed to avoid interference with obstacles, Since the planar antenna unit is directed toward the subject and composed of a plurality of planar antenna elements, the antenna directivity is always directed toward the wireless microphone transmitter, and a video camera that can obtain high directivity gain is equipped. A wireless antenna device of a wireless receiving device can be provided.

  In the present invention, the wireless microphone transmitter is equipped with two wireless antenna devices, and the wireless antenna device on the side not affected by the hand holding the wireless microphone transmitter is automatically selected and transmitted. A wireless antenna device of a wireless microphone transmitter that can ensure a high antenna gain can be provided.

1 is a basic conceptual diagram of a video camera equipped with a wireless antenna device according to a first embodiment of the present invention. The basic concept figure of the wireless antenna apparatus with which the video camera in the 2nd Embodiment of this invention is equipped Explanatory drawing of operation | movement of the wireless antenna apparatus in the 2nd Embodiment of this invention. The basic concept figure of the video camera provided with the wireless antenna apparatus in the 3rd Embodiment of this invention It is a figure which shows the structure of the wireless microphone transmitter in the 4th Embodiment of this invention, (A) is a figure which shows the structure of the wireless antenna apparatus incorporated in a wireless microphone transmitter, (B) is the lower part of a wireless microphone The figure which shows the state held with the hand (C) is the figure which shows the state where the upper part of the wireless microphone is held with the hand The figure which shows the structure of the wireless antenna apparatus incorporated in the wireless microphone transmitter in the 5th Embodiment of this invention. Configuration diagram of a wireless antenna device with a sleeve antenna fixed to the top of a conventional video camera Configuration diagram of a wireless antenna device configured with an inverted L antenna disposed inside a conventional wireless microphone casing

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 31, 41 Planar antenna part 2 Receiving device 3 Connector part 4 Video camera 5 Sleeve antenna part 6 Dielectric board 7 Ground board 8a-8d Planar antenna element 9a-9d Through-hole 10a, 10b Power divider 11a, 11b Connector part 12 Photographer (human body)
13 Directionality in the Present Invention 14 Directionality in Conventional Example 15 Subject 16 Connection Cable 17 Wireless Microphone Transmitter 18 Dielectric Helical Antenna 19 Transmission Line 20 Loop Antenna 21 Transmission Line 22 High Frequency Signal Switching Circuit 23 Directional Coupler 24 Transmission Circuit 25 Detection control unit 26 Microphone unit 27 Hand (human body)
28 Circulator

Claims (3)

A first antenna disposed at a lower part of the wireless microphone, a second antenna disposed near the microphone unit at a certain distance from the first antenna, and a voice signal from the microphone unit are processed to generate a high-frequency transmission signal. A transmission circuit for outputting, a high-frequency signal switching circuit for switching a high-frequency transmission signal from the transmission circuit to either the first antenna or the second antenna, and the first signal inserted between the high-frequency signal switching circuit and the transmission circuit. A directional coupler that detects a reflection component of a high-frequency transmission signal from one antenna and a second antenna, and a method that receives a result of detection of the reflection component by the directional coupler and that has a low reflection component from the transmission circuit. A detection control unit that switches the high-frequency signal switching circuit to connect to the antenna of
The detection control unit selects the antenna having the smaller reflection component of the first antenna or the second antenna, and automatically switches and transmits the high-frequency transmission signal from the transmission circuit to the antenna having the smaller reflection component. A wireless microphone characterized by doing so. A first antenna disposed at the bottom of the wireless microphone, a second antenna disposed in the vicinity of the microphone unit at a certain distance from the first antenna, and a transmission for processing and outputting a voice transmission signal from the microphone unit A circuit and a circulator for transmitting a high-frequency transmission signal from the transmission circuit to a first antenna and transmitting a reflected signal from the first antenna to a second antenna;
An antenna that automatically transmits a high-frequency transmission signal from a transmission circuit for transmission to the first antenna and transmits it to the second antenna via a circulator when there is a reflected signal from the first antenna. A wireless microphone characterized by being selected. 3. The wireless microphone according to claim 1, wherein the first antenna is a helical antenna, and the second antenna is a loop antenna.

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