WO2010021096A1

WO2010021096A1 - Noise cancellation device, and noise cancellation module and electronic device using same

Info

Publication number: WO2010021096A1
Application number: PCT/JP2009/003733
Authority: WO
Inventors: 恒岡道朗; 藤島明; 北川元祥; 福島奨
Original assignee: パナソニック株式会社
Priority date: 2008-08-18
Filing date: 2009-08-05
Publication date: 2010-02-25
Also published as: JP5104953B2; JPWO2010021096A1; CN102124657A

Abstract

Disclosed is a noise cancellation device comprising a first antenna arranged within a shield and a noise cancellation unit into which noise signals received by the first antenna are input. Based on the noise signals input via the first antenna from a noise source, the noise cancellation unit attenuates the noise signals from the noise source, which are included in high-frequency signals received by a second antenna.

Description

Noise canceling device, noise canceling module using the same and electronic device

The present invention relates to a noise canceling device used in various electronic devices.

FIG. 16 is a block diagram of a conventional noise cancellation device. The block diagram of the noise cancellation apparatus used for television receiving portable terminals, such as a mobile telephone, is shown. In FIG. 16, an image / sound output unit 8 for the screen 2 is provided in the main body 1, and a signal processing unit 9 and a control unit 10 are connected to the image / sound output unit 8.

A signal line and a control line are connected between the main body 1 and the image receiver 5. Further, a ground line 5 b is connected between the ground 1 a of the main body 1 and the ground 5 a of the image receiver 5. An antenna matching unit 11, a tuner 12, and a demodulation unit 13 are sequentially connected to the antenna 7 of the image receiver 5. The output signal of the demodulating unit 13 is processed by the signal processing unit 9 and supplied to the image / sound output unit 8 so that the television broadcast can be viewed through the screen 2 and the speaker 14.

The antenna matching unit 11 includes a matching unit 15 on the antenna 7 side and a subsequent amplifier 16, thereby improving the receiving sensitivity and achieving impedance matching even with the short antenna 7. A noise cancellation unit 17 is connected between the antenna matching unit 11 and the tuner 12, and the noise cancellation unit 17 supplies a noise cancellation signal between the antenna matching unit 11 and the tuner 12.

That is, the noise canceling unit 17 supplies a noise signal similar to that which enters the antenna 7 from the main body 1 to the phase controller 19 from the ground 18 of the main body 1 of the portable device, where the noise signal is inverted and the noise is inverted. Create a cancel signal. Note that the noise cancellation signal supplied to the noise cancellation unit 17 may use the ground in the image receiver 5 instead of the ground 18 of the main body 1.

However, in the conventional noise cancellation device, the noise is picked up by the ground 18 of the main body 1. Since the ground 18 of the main body 1 also receives a television signal received by the antenna 7, the television signal received by the ground 18 of the main body 1 is input to the noise canceling unit and, as a result, received by the antenna 7. It works to cancel the TV signal. Therefore, the conventional noise cancellation apparatus has a problem that a desired received signal is deteriorated.

As prior art document information related to the invention of the present application, for example, Patent Document 1 is known.

JP 2008-22294 A

The noise cancellation apparatus of the present invention includes a first antenna disposed in a shield, and a noise cancellation unit to which a noise signal from a noise source received by the first antenna is input. Based on the noise signal from the noise source input from the antenna, the noise signal from the noise source included in the high-frequency signal received by the second antenna is attenuated.

In the present invention, since the first antenna is disposed in the shield, it is possible to suppress reception of a desired signal (applicable to a television signal in the above) coming from the outside. Further, since a noise signal from a noise source near the first antenna is blocked by the shield and is difficult to be input to the second antenna, a noise canceling device having high reception performance can be realized.

FIG. 1 is a block diagram of a noise canceling apparatus and electronic equipment using the same according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the noise cancellation device according to the first embodiment. FIG. 3 is a top view of the first antenna in the first embodiment. 4 is a top view of another first antenna according to Embodiment 1. FIG. FIG. 5 is a bottom view of the first antenna in the first embodiment. FIG. 6 is a side sectional view of the first antenna and the shield in the first embodiment. FIG. 7 is another side sectional view of the first antenna and the shield plate in the first exemplary embodiment. FIG. 8 is a detailed view of a shield plate end in the first embodiment. FIG. 9 is a side sectional view of the configuration for improving the sensitivity of the first antenna in the first embodiment. FIG. 10 is a block diagram of the noise cancellation apparatus according to the first embodiment. FIG. 11A is a top view of the noise cancellation device according to Embodiment 2 of the present invention. FIG. 11B is a bottom view of the noise cancellation device. FIG. 12 is a block diagram of the noise cancellation apparatus according to the second embodiment. FIG. 13 is a characteristic diagram of the power supply / control signal of the control unit. FIG. 14A is an upper perspective view of the noise cancellation device according to Embodiment 3 of the present invention. FIG. 14B is a lower perspective view of the noise cancellation device. FIG. 14C is a front perspective view of the main board on which the noise cancellation device is mounted. FIG. 15A is a top view of the noise cancellation module according to Embodiment 4 of the present invention. FIG. 15B is a bottom view of the noise cancellation module. FIG. 16 is a block diagram of a conventional noise cancellation device.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings.

An example in which the noise cancellation device of the present invention is mounted on an electronic device intended to receive, for example, a television broadcast signal as a high-frequency signal will be described.

FIG. 1 is a block diagram of a noise canceling apparatus and an electronic apparatus using the same according to Embodiment 1 of the present invention. The noise cancellation device 30 according to the first embodiment of the present invention includes a first antenna 32 disposed inside the shield 31 and a noise cancellation unit 33 to which a noise signal received by the first antenna 32 is input. Yes.

The image receiver 35 includes a second antenna 37, an antenna matching unit 38 to which a TV signal received by the second antenna is input, a noise canceling device 30, a tuner 39, and a demodulator 40. Yes.

The output signal of the antenna matching unit 38 is combined with the output signal of the noise cancellation device 30 and then input to the tuner 39. The tuner 39 performs amplification, frequency conversion, noise removal, and the like on the input television signal and outputs it to the demodulation unit 40. The demodulator 40 multi-modulates the modulated television signal and outputs the demodulated signal to the signal processor 41.

An image / sound output unit 42 for outputting images and sounds to the display unit 43 and the speaker 44 is provided in the main body 34, and a control for controlling the image / sound output unit 42 and the signal processing unit 41 is provided. A portion 47 is provided.

Between the main body 34 and the image receiver 35, a signal line for electrically connecting the signal processing unit 41 and the demodulation unit 40, and a control unit 47, a tuner 39, a demodulation unit 40, and a control unit 49 are electrically connected. The control line to be connected is connected. Further,

ground lines

36 a and 36 b are connected between the

grounds

34 a and 34 b of the main body 34 and the grounds 35 a and 35 b of the image receiver 35.

The output signal of the demodulating unit 40 is processed by the signal processing unit 41 and supplied to the image / sound output unit 42, whereby the television broadcast can be viewed by the display unit 43 and the speaker 44.

The antenna matching unit 38 includes a matching unit 45 on the second antenna 37 side and an amplifier 46 subsequent thereto. The matching unit 45 has a role of achieving impedance matching between the second antenna 37 and the amplifier 46. The amplifier 46 has a role of amplifying a high frequency signal received by the second antenna 37 and improving NF (Noise Figure) characteristics of the system.

A noise canceling unit 33 is connected between the antenna matching unit 38 and the tuner 39 configured as described above. The noise canceling unit 33 transmits a noise canceling signal between the antenna matching unit 38 and the tuner 39. Supply. The noise canceling device 30 picks up the noise similar to the noise entering the second antenna 37 from the noise source near the first antenna 32 by the first antenna 32 and supplies the picked up noise to the phase controller 48. To do.

The phase controller 48 changes the noise phase based on the control signal input from the control unit 49 and is included in the TV signal when it is combined with the TV signal output from the antenna matching unit 38. The phase of the noise input from the first antenna 32 is adjusted so that the phase is opposite to the phase of the existing noise.

The output signal of the phase controller 48 is input to the gain controller 50. The gain controller 50 changes the amplitude of noise based on the control signal input from the control unit 49 and is included in the TV signal when it is combined with the TV signal output from the antenna matching unit 38. The amplitude of noise input from the first antenna 32 is adjusted so as to be the same as the absolute value of the amplitude of noise.

The output signal of the gain controller 50 is input to the filter 51. The filter 51 is a band-pass filter (BPF) whose pass band is the frequency bandwidth of the television signal received by the second antenna 37, and has a role of attenuating noise other than the frequency band of the television signal.

The demodulator 40 derives received signal quality information (for example, an index indicating the quality of the received signal such as C / N (Carrier / Noise), BER (Bit Error Rate)) of the input television signal. The received signal quality information is supplied to the control unit 47. The control unit 47 transmits a control signal to the control unit 49 based on the received signal quality information, and the control unit 49 controls the phase controller 48 and the gain controller 50 based on the control signal.

For example, if the noise increases after combining the output signal of the antenna matching unit 38 and the output signal of the noise canceling device 30, the received signal quality information derived by the demodulator 40 becomes inferior. The unit 47 transmits a control signal for adjusting the phase and amplitude of the noise picked up by the first antenna 32 to the control unit 49.

Thereafter, the phase and amplitude of the noise are adjusted, and for example, it is assumed that the noise is suppressed after combining the output signal of the antenna matching unit 38 and the output signal of the noise cancellation device 30. In this case, the received signal quality information derived by the demodulator 40 is good, and the controller 47 sends the control signal to the controller 49 so that the settings of the phase controller 48 and the gain controller 50 are fixed. Send.

Here, for example, when the first antenna 32 also receives a television signal, the output signal of the noise cancellation device 30 includes the television signal, and the television signal received by the second antenna 37 is suppressed. Can be. As a result, the S / N (Signal / Noise) ratio of the television signal input to the demodulator deteriorates, and the reception characteristics of the electronic device deteriorate.

The noise cancellation device 30 according to the first embodiment is an antenna that is difficult to receive a television signal because the first antenna 32 is disposed inside the shield 31.

Specifically, when the periphery of the first antenna 32 is covered with the conductive shield 31, the radiation resistance of the first antenna 32 is compared with the radiation resistance of the second antenna 37 that is not disposed inside the shield. And it becomes extremely small. Thereby, the S / N ratio of the signal received by the first antenna 32 can be made smaller than the S / N ratio of the signal received by the second antenna 37, and the television input to the demodulator 40 can be achieved. The S / N ratio of the signal can be improved.

In addition, it is assumed that noise pickup is difficult because the radiation resistance of the first antenna 32 is low. However, since the first antenna 32 is disposed in the vicinity of the noise source, the noise source and the electromagnetic field coupling are used. Noise can be received.

Specifically, the sensitivity of the first antenna 32 to electromagnetic coupling increases with the cube of the distance as it approaches the first antenna 32, whereas the sensitivity to reception of a television signal arriving from a distance is first. As the antenna 32 is approached, the distance increases to the first power. For this reason, the first antenna 32 has a high sensitivity to noise sources, and on the other hand, the television signal may have a low radiation resistance due to being arranged inside the shield 31. Influential and has only a small sensitivity (references: Illustrated antenna (P153 [Formula 3.5], P180 [Formula 3.41], Author: Naohisa Goto, Publisher: The Institute of Electronics, Information and Communication Engineers)).

From the above, a feature of the present invention is that an antenna having a low radiation resistance, which is not normally employed by those skilled in the art, is employed as the first antenna 32. The present invention dares to employ an antenna having a low radiation resistance to lower the sensitivity to a TV signal coming from a distance, and conversely, to increase the noise by placing the first antenna in the vicinity of the noise source. It has a configuration with sensitivity.

Furthermore, since the amount of noise input from the noise source to the second antenna 37 can be suppressed by the shield 31, the S / N ratio of the output signal of the second antenna 37 can also be improved.

FIG. 2 is a perspective view of the noise canceling apparatus according to the first embodiment. FIG. 2 shows an example of a specific configuration of the first antenna 32 and the shield 31.

In FIG. 2, a noise canceling unit 33 and a semiconductor IC as a noise source 53 are mounted above a main board 52 (in FIG. 1, a board built in the image receiver 35) built in the electronic device. ing.

A first antenna 32 for picking up noise is installed in the vicinity of the noise source 53, and a shield 31 is installed so as to substantially surround the noise source 53 and the first antenna 32. The shield 31 is at least partially formed of a conductive member, and the entire periphery of the noise source 53 and the first antenna 32 may be covered with the conductive member. A hole having a small diameter (for example, a diameter of about 1/10 or less of the wavelength of the received signal) may be opened. This is because if the hole diameter is small with respect to the wavelength, it is difficult for signals coming from the outside to leak into the shield.

The shield 31 may be realized by a shield plate mounted above the main board 52 and a conductive pattern formed on the main board 52. Thereby, the shield 31 can be easily realized. Furthermore, the shield 31 may be connected to the ground where the main substrate 52 is formed in a direct current manner, or may not be connected. Regardless of whether or not the shield 31 and the ground of the main board 52 are connected, if the first antenna 32 is disposed inside the shield 31, the first antenna 32 is configured to be difficult to receive a TV signal coming from the outside. Because it can.

In FIG. 2, the first antenna 32 is a loop antenna that is a balanced antenna. If a balanced antenna is employed as the first antenna 32, the occurrence of the common mode on the transmission line 54 that electrically connects the first antenna 32 and the noise canceling unit 33 can be suppressed, and basically the first mode is determined by the differential mode. Noise picked up by the antenna 32 can be transmitted. Thereby, it can suppress that the transmission line 54 carries out an antenna operation | movement, the transmission line 54 operate | moves as an antenna, and it can prevent that the television signal which comes from the outside by the transmission line 54 is received. Therefore, it is possible to provide a noise canceling device that can realize an electronic device having high reception performance.

The first antenna 32 has a shape that is as symmetrical as possible with respect to a feeding point (not shown) of the first antenna 32 so that the first antenna 32 can easily operate as a balanced antenna. The mounting position of the first antenna 32 with respect to the noise source 53 may be devised. This is because the noise source 53 that is electromagnetically coupled to the first antenna 32 also operates as a part of the antenna of the first antenna 32, so that the noise source 53 including the peripheral components of the first antenna 32 is as symmetrical as possible. This is because it is easier to operate the first antenna 32 as a balanced antenna.

In FIG. 2, the transmission line 54 is a feeder line that is a balanced transmission line. When a coaxial line, which is an unbalanced transmission line, is employed for the transmission line 54, a common mode is likely to occur on the transmission line 54, so that the transmission line 54 also easily operates as an antenna.

Further, when a balanced transmission line is adopted as the transmission line 54, it is possible to suppress the transmission line 54 from operating as an antenna, and it is possible to make it difficult to receive a television signal coming from the outside.

Further, the noise source 53 may be a tuner 39 disposed near the second antenna 37, or a demodulator 40, a display unit 43 that emits a large noise signal, a signal processor 41, or the like. It is good.

FIG. 3 is a top view of the first antenna in the first embodiment. 4 is a top view of another first antenna according to Embodiment 1. FIG.

3 and 4 show a specific configuration of the first antenna 32. FIG. In FIG. 3, the first antenna 32 includes a loop antenna 56 formed on the flexible substrate 55.

The loop antenna 56 is a magnetic current type antenna (antenna in which the operation of a minute magnetic dipole is dominant), and compared with a current type antenna such as a dipole antenna (antenna in which the operation of a minute electric dipole is dominant), It has a higher sensitivity to magnetic fields than electric fields. For this reason, when a portion where a large amount of current flows is a noise source, the magnetic field type antenna such as the loop antenna 56 shown in FIG. Then, the amount of noise pickup can be increased.

In FIG. 4, the first antenna 32 is realized by forming the folded dipole antenna 57 on the flexible substrate 55. The folded dipole antenna 57 is a current type antenna and has higher sensitivity to an electric field than a magnetic field as compared with a magnetic current type antenna such as the loop antenna 56 of FIG. Therefore, when a site where a high potential difference is generated is a noise source, the ratio of the electric field to the magnetic field is high, and therefore, when a current-type antenna such as a dipole antenna is used, the amount of noise pickup is increased. I can do things.

3 and 4 are both balanced antennas, but the present invention is not limited to this, and a monopole antenna or the like that is an unbalanced antenna may be adopted. By employing an unbalanced antenna, the first antenna 32 can be reduced in size.

The first antenna 32 shown in FIGS. 3 and 4 is disposed in the vicinity of the noise source 53. However, since the first antenna 32 is configured by the flexible substrate 55, it can be easily mounted in the vicinity of the uneven noise source. Can do. In this case, an adhesive portion may be added to at least one surface of the flexible substrate of the first antenna 32 shown in FIGS. 3 and 4, and the adhesive portion may be attached in the vicinity of the noise source 53.

In addition, since the mounting position of the first antenna 32 is often determined after the design of the electronic device is completed, according to the first embodiment, the position near the noise source can be easily obtained after the design of the electronic device is completed. It has the advantageous effect that it can be specified and pasted.

In addition, you may form the shield pattern 58 in the surface which is not the formation surface of the loop antenna 56 of the flexible substrate 55 of FIG. FIG. 5 is a bottom view of the first antenna in the first embodiment. FIG. 5 shows a view in which a shield pattern 58 is formed on the back surface of the first antenna 32 shown in FIG. In this state, by arranging the surface on which the shield pattern 58 is not formed so as to be close to the noise source 53, it is possible to improve the effect of suppressing reception of an incoming TV signal from the outside.

For example, in FIG. 2, a shield plate on the main substrate 52 of the shield 31 is attached by adhering the surface of the first antenna 32 shown in FIG. It is also possible to eliminate Accordingly, the electronic device can be reduced in weight and thickness, and the manufacturing efficiency of the noise cancellation device can be improved.

Note that the shield pattern 58 of FIG. 5 and the shield pattern (not shown) formed on the main substrate 52 may be DC-connected or insulated. The shield pattern 58 and the shield pattern (not shown) formed on the main board 52 are insulated via a small gap (for example, a gap width of about 1/10 of the wavelength) with respect to the wavelength of the television signal. However, it is difficult for the television signal to leak from the gap.

When the shield pattern 58 and the shield pattern (not shown) formed on the main substrate 52 are galvanically insulated, the manufacturing process can be simplified and the manufacturing efficiency of the noise canceling device can be improved. .

FIG. 6 is a side sectional view of the first antenna and the shield in the first embodiment. FIG. 6 is a side sectional view showing a specific example of the first antenna 32 and the shield 31 in FIG. A noise source 53 is mounted above the main substrate 52, and a shield is formed by a shield plate 59 and a shield pattern 60 formed on the back surface of the main substrate 52 so as to surround it. It should be noted that the shield plate 59 and the shield pattern 60 may be DC-connected or may not be conductive. A first antenna 32 is disposed inside the shield plate 59 facing the noise source 53 and picks up noise from the noise source 53.

FIG. 7 is another side cross-sectional view of the first antenna and the shield plate in the first embodiment. FIG. 7 is a cross-sectional view from a side different from the side cross-sectional view of FIG. 6, and only the shield plate 59 and the first antenna 32 are shown for easy understanding. In FIG. 7, the first antenna 32 is disposed inside the shield plate 59, and the transmission line portion of the first antenna 32 is configured to be folded at the end of the shield plate 59.

FIG. 8 is a detailed view of the end portion of the shield plate in the first embodiment. FIG. 8 is an enlarged view of the end A of the shield plate 59 in FIG. FIG. 8 is a view when the end A is viewed from the same side as in FIG. In FIG. 8, the flexible substrate 55 on which the transmission line 61 of the first antenna is formed is disposed so as to cover the surface from the back surface to the surface of the first fixed end portion 62 of the shield plate 59.

The shield plate 59 is fixed to the main board 52 by soldering the second fixed end portion 63. The noise picked up by the first antenna 32 passes through a land on the main board (not shown) electrically connected to the noise canceling unit 33 mounted on the main board 52 and the first fixed end 62 in FIG. By electrically connecting the transmission line 61 to be covered, the noise cancellation unit 33 is supplied. At this time, the flexible substrate 55 is arranged so as to cover the entire surface from the back surface to the front surface of the first fixed end portion 62 of the shield plate 59 so that the shield plate 59 and the land on the main substrate are not connected in a direct current manner. Has been.

Further, the flexible substrate 55 may be designed to be wider than the first fixed end 62 so that the first fixed end 62 is not exposed from the flexible substrate 55. Thus, the shield plate 59 and the main board land can be prevented from being connected in a direct current manner.

If there is no concern that the shield plate 59 and the land on the main board are connected in a direct current manner, the flexible board 55 is moved from the back surface of the first fixed end 62 of the shield board 59 to the surface as shown in FIG. However, it may be arranged not to cover the entire surface but to cover only the back surface. Thereby, the manufacturing efficiency of a noise cancellation apparatus can be improved.

Furthermore, an adhesive portion may be provided on a part of the flexible substrate constituting the first antenna 32 of FIG. 7 and attached to the back surface of the shield plate 59 using this. Thereby, the manufacturing efficiency of a noise cancellation apparatus can be improved.

Also, the first antenna 32 may be arranged closer to the noise source 53 in order to improve the noise pickup sensitivity of the first antenna 32 of FIG. An embodiment of this realization is shown using FIG. FIG. 9 is a side sectional view of the configuration for improving the sensitivity of the first antenna in the first embodiment.

9 differs from FIG. 7 in that a spacer portion 64 is newly installed inside the shield plate 59 and the first antenna 32 is arranged on the inner surface thereof. As a result, the distance between the noise source 53 and the first antenna 32 can be made narrower, and the sensitivity of noise reception can be further improved.

FIG. 10 is a block diagram of the noise cancellation apparatus according to the first embodiment. FIG. 10 shows a configuration for the first antenna 32 to receive larger noise. In FIG. 10, an amplifier 65 is attached to the first antenna 32 which is a balanced antenna. Since the first antenna 32 is a balanced antenna, the amplifier 65 also has a symmetric configuration. Power supply to the amplifier 65 is performed via a balanced transmission line 54.

Specifically, a capacitor 66 that passes the TV signal but cuts off the DC power source 67a is connected to both ends of the transmission line 54 on the first antenna 32 side and the noise canceling unit 33 side, and the DC power source 67a passes. However, an inductor 67 that cuts off the TV signal is connected. The DC power supply 67a is supplied to the amplifier 65 through the inductor 67. This eliminates the need to add a new power supply line.

In FIG. 10, since the balanced transmission line 54 is used, the capacitor 66 and the inductor 67 are configured with substantially symmetrical element values and connection positions.

(Embodiment 2)
Hereinafter, a noise canceling apparatus according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 11A is a top view of the noise canceling apparatus according to Embodiment 2 of the present invention, and FIG. 11B is a bottom view of the noise canceling apparatus.

In FIG. 11A, the noise cancellation unit 33 is mounted above the flexible substrate 55, and the first antenna 32 is formed on the flexible substrate so as to surround the noise cancellation unit 33.

In FIG. 11B, a shield pattern 58 is formed on the entire back surface of the flexible substrate 55, and the shield pattern 58 is electrically connected to the outer peripheral shield pattern of FIG.

A part of the shield pattern 58 in FIG. 11A is electrically connected to the shield pattern 60 of the main board in FIG. 6 to form the shield 31 in FIG. As shown in FIG. 11A, an advantageous effect that the shield 31 can be easily formed in the vicinity of the noise source by disposing the noise canceling portion 33 having a certain thickness at the substantially central portion of the flexible substrate 55 is obtained. It is done.

Further, if the first antenna 32 and the noise canceling unit 33 are arranged inside the shield 31 as shown in FIG. 11A, the transmission line 54 is arranged outside the shield 31 as shown in FIG. Since nothing happens, it is possible to prevent the transmission line 54 from receiving a television signal.

11A shows a configuration in which the noise cancellation unit 33, the first antenna 32, and the shield pattern 58 are formed and mounted on the flexible substrate 55. FIG. However, the present invention is not limited to this. For example, the tuner 39 and the demodulator 40 may be mounted on the flexible board 55 in FIG. 11A. Thereby, the transmission line which electrically connects the tuner 39 and the demodulation part 40, and the noise cancellation part 33 can be shortened, and a transmission loss can be reduced.

A signal line 68 connected to the tuner 39 and the antenna matching unit 38 in FIG. 1 is electrically connected to the noise canceling unit 33, and this signal line 68 is connected between the power feeding unit of the first antenna 32. Is arranged. This can prevent the balance operation of the first antenna 32 from being hindered.

In FIG. 11A, the shield pattern 58 is formed on the outer peripheral portion of the flexible substrate 55. However, a configuration without this may be used. Then, an adhesive portion (not shown) may be added to the surface of FIG. 11A of the flexible substrate 55 and attached to the main substrate 52 of FIG. 6 via this adhesive portion.

Even if there is a gap between the shield pattern 60 of the main board 52 in FIG. 6 and the shield pattern 58 in FIG. 11B, if the gap width is sufficiently small with respect to the wavelength of the television signal, the television signal is transmitted through the gap. However, it is difficult to leak into the shield 31.

FIG. 12 is a block diagram of the noise cancellation apparatus according to the second embodiment. FIG. 12 shows an embodiment of a method for connecting the noise canceling unit 33, the tuner 39, and the control unit 47 of FIG. 11A. 12, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

12, the capacitor 68a passes a signal received by the second antenna 37 of FIG. 1 such as a TV signal, but has a role of cutting off a control signal and a power source transmitted from the control unit 47 in general. The inductor 69 passes a control signal and a power source transmitted from the control unit 47, but has a role of blocking generally a signal received by the second antenna 37 of FIG.

The operation of the block diagram in FIG. 12 will be described. The television signal received by the second antenna 37 in FIG. 1 is supplied to the tuner 39 through the capacitor 68a. The frequency is converted by the tuner 39 and then output to the demodulator 40.

The demodulator 40 demodulates the input TV signal and receives received signal quality information (for example, C / N (Carrier / Noise), BER (Bit Error Rate)) of the input TV signal. An index indicating the signal quality) is derived.

The received signal quality information is supplied to the control unit 47. The control unit 47 generates a control signal based on the received signal quality information, and transmits the control signal to the control unit 49 via the inductor 69. Here, the power supply to the noise canceling unit 33 is also superimposed on the control signal and supplied to the noise canceling unit 33 via the inductor 69.

FIG. 13 is a characteristic diagram of the power supply / control signal of the control unit. FIG. 13 shows a position example of the waveform of a signal in which the power supply voltage output from the control unit 47 to the noise cancellation unit 33 and the control signal are superimposed. The horizontal axis represents time, and the vertical axis represents voltage value. In FIG. 13, a characteristic 130 represents a waveform of a signal output from the control unit 47 to the noise cancellation unit 33. The characteristic 131 is a voltage value necessary for the noise canceling unit 33, and a voltage value higher than this is always output from the control unit 47 to the noise canceling unit 33.

Although not shown in FIG. 12, the signal of the characteristic 130 of FIG. 13 that has passed through the inductor 69 in the noise canceling unit 33 is converted to a constant voltage value of the characteristic 131 of FIG. 13 by a regulator (not shown). After that, it is supplied to each active element constituting the noise canceling unit 33.

Further, the control of the control unit 49 is performed by a control signal generated with voltage values of four stages of the characteristic 135 from the characteristic 132 that is equal to or higher than the voltage value of the characteristic 131 of FIG. By adopting such a configuration, it is not necessary to arrange transmission lines for control signals and power supplies, and manufacturing efficiency can be improved.

In addition, in FIG. 13, although the structure about the control signal and power supply to the noise cancellation part 33 was demonstrated, you may supply the control signal and power supply to the antenna matching device 38 by the same method. Thereby, the manufacturing efficiency of the electronic device in which the noise cancellation device is mounted can be increased.

(Embodiment 3)
Hereinafter, a noise canceling apparatus according to Embodiment 3 of the present invention will be described with reference to the drawings. 14A is an upper perspective view of the noise canceling apparatus according to Embodiment 3 of the present invention, FIG. 14B is a lower perspective view of the noise canceling apparatus, and FIG. 14C is a front perspective view of a main board on which the noise canceling apparatus is mounted. .

14A and 14B, the noise cancellation device 30 includes a ground pattern 71 formed on the upper surface of a base body 70 made of a dielectric or magnetic material, a first antenna 32 formed on the lower surface of the base body 70, And a sub-board 72 mounted in a recess 73 formed in the center of the lower surface of the base body 70. A noise canceling unit 33 is mounted on the sub board 72 and is electrically connected to the first antenna 32.

14A and 14B is mounted above the main board 52 so that the lower surface side thereof is in close contact with the main board 52. At the time of mounting, the ground pattern 71 formed on the lower surface of FIG. 14B and the ground pattern 74 on the main substrate surface of FIG. 14C are electrically connected by solder or the like.

Also, a ground pattern (not shown) is formed on the back surface of the main substrate 52 and is electrically connected to the ground pattern 74 of the main substrate 52. With such a structure, the shield 31 of FIG. 1 is realized so as to substantially surround a noise source (not shown).

14C is electrically connected to a tuner (not shown), a control unit (not shown), etc. mounted on the main board 52, and is electrically connected to the noise cancellation unit 33 of FIG. 14B. The connected land 76 and the land 75 on the main board 52 are electrically connected by solder or the like.

If a module in which the first antenna 32, the ground pattern 71, and the noise canceling unit 33 are integrated as shown in FIG. 14B is used, the noise canceling device of the present invention can be reduced in size, as shown in FIG. Since the transmission line 54 is not disposed outside the shield 31, it is possible to prevent the transmission line 54 from receiving a television signal.

In FIG. 14B, the noise canceling unit 33 is mounted on the substrate 70 after being mounted on the sub-board 72, but the noise canceling unit 33 may be mounted directly on the substrate 70. Thereby, the manufacturing efficiency of the noise cancellation apparatus 30 can be improved.

(Embodiment 4)
Hereinafter, a noise cancellation module according to Embodiment 4 of the present invention will be described with reference to the drawings. FIG. 15A is a top view of the noise cancellation module according to Embodiment 4 of the present invention, and FIG. 15B is a bottom view of the noise cancellation module.

15A and 15B, the noise cancellation module 80 includes a ground pattern 78 formed on the back surface of the sub-substrate 77 and a second surface formed on the surface of the sub-substrate 77 where the ground pattern 78 is not formed on the back surface. The antenna 37 includes a first antenna 32 and a noise canceling portion 33 arranged in a region where a ground pattern 78 is formed on the back surface of the sub substrate 77.

The location of the noise source received by the second antenna 37 is often relatively close to the second antenna 37. This is because as the distance from the noise source increases, the noise electric field or magnetic field attenuates as the cube of the distance.

Since the noise source position of the noise to be removed by the noise cancellation device 30 exists in the vicinity of the second antenna 37, as shown in FIG. 15A, the noise cancellation module in which the noise cancellation device 30 and the second antenna 37 are integrated. Is provided, the reception noise attenuation performance of the second antenna 37 can be improved while being small.

As shown in FIGS. 15A and 15B, the noise matching module 38, the tuner 39, the demodulator 40, and the like may be mounted on the noise cancellation module 80. Thereby, size reduction can be achieved and reduction in size and weight of an electronic device equipped with the noise cancellation module of the present invention can be promoted.

Note that a flexible substrate may be adopted as the sub-substrate 77, an adhesive portion may be formed on the surface side of the sub-substrate 77, and the sub-substrate 77 may be disposed on the main substrate via this adhesive portion. Thereby, the ease of mounting on the main substrate can be improved.

In addition, although the ground pattern 78 is not formed on the back surface of the region where the second antenna 37 is formed, the second antenna 37 can increase the radiation resistance and improve the reception performance of the television signal. can do. This makes it possible to increase the S / N ratio between a desired wave such as a television signal and noise.

According to the present invention, since the first antenna is arranged in the shield, it is possible to suppress reception of a desired signal such as a television signal coming from the outside, and noise from a noise source in the vicinity of the first antenna. Is blocked by the shield and is difficult to be input to the second antenna, so that a noise canceling device having high reception performance can be realized. Therefore, the noise cancellation apparatus of the present invention can be used for various electronic devices, communication devices, and the like, and can improve the reception performance of these devices.

DESCRIPTION OF SYMBOLS 30 Noise cancellation apparatus 31 Shield 32 1st antenna 33 Noise cancellation part 34 Main body 35 Image receiver 37 2nd antenna 38 Antenna matching device 39 Tuner 40 Demodulation part 41 Signal processing part 42 Image / audio output part 43 Display part 44 Speaker 45 Matching Unit 46 amplifier 47 control unit 48 phase controller 49 control unit 50 gain controller 51 band pass filter

Claims

A first antenna disposed within the shield;
A noise cancellation unit to which a noise signal from a noise source received at the first antenna is input;
The noise cancellation unit attenuates a noise signal from the noise source included in a high-frequency signal received by the second antenna based on a signal input from the first antenna.
The noise cancellation apparatus according to claim 1, wherein the first antenna is a balanced antenna.
The noise cancellation apparatus according to claim 1, wherein the first antenna and the noise cancellation unit are electrically connected by a balanced transmission line.
The noise cancellation device according to claim 1, wherein the noise cancellation unit is disposed in the same shield as the first antenna.
The shield is composed of a conductive pattern on a substrate and a shield member,
The noise canceling device according to claim 1, wherein the first antenna is formed by a conductive pattern on a surface or inside of the shield member.
The shield is composed of a conductive pattern on a substrate and a shield member,
2. The noise canceling device according to claim 1, wherein the first antenna is formed by a conductive pattern on a surface or inside of the antenna member, and the antenna member is fixed inside the shield member.
The noise cancellation device according to claim 5, wherein the noise cancellation unit is mounted on the shield member.
The noise cancellation device according to claim 6, wherein the noise cancellation unit is mounted on the antenna member.
The noise canceling device according to claim 5, wherein the shield member has flexibility.
The noise cancellation apparatus according to claim 1, wherein a noise signal from the noise source received by the first antenna is input to the noise cancellation unit via an amplifier.
A first antenna disposed within the shield;
A noise canceling unit to which a noise signal from a noise source received at the first antenna is input;
A second antenna disposed outside the shield,
The noise cancellation unit attenuates a noise signal from the noise source included in a high frequency signal received at the second antenna based on a noise signal from the noise source input from the first antenna. module.
A noise cancellation module according to claim 11;
A signal processing unit electrically connected to the noise cancellation module;
An electronic device having a display unit electrically connected to the signal processing unit.