JP2011223485A - Mobile wireless terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid cost increases for a mobile wireless terminal containing a plurality of wireless systems due to increased size of the terminal and number of parts because of the requirement for multiple noise detectors to detect different noise components each deteriorating the sensitivity.SOLUTION: In a multiple wireless system environment, noise component detection in a time division manner allows detection of noise components to be performed at a detection part for detecting a single series of noise component, instead of using multiple detection parts for addressing the multiple wireless systems, thereby allowing the mobile wireless terminal to be made compact and reducing the cost.

Description

  The present invention relates to a portable wireless terminal having a noise canceling function in a device that reduces sensitivity deterioration by canceling noise generated in the device that wraps around a receiving antenna.

  In a receiving device for receiving radio signals used for communication and broadcasting, a signal generated by a circuit such as a CPU or a memory, an arithmetic circuit for processing a received signal, or a reference clock generator for operating them, or the signal There is a problem of internal interference in which the higher harmonic component becomes an interference component in the radio frequency band of the received signal and degrades the quality of the received signal.

  In recent years, receivers have become more multifunctional, and the number of circuits built in them has been increasing. In addition, as the signals handled in the receiving apparatus are digitized, the processing speed and the amount of information to be processed are also increasing. In addition, receiving devices are required to be further downsized, and antennas for receiving signals are becoming smaller and built-in. For this reason, the interference component of internal interference is increasing. In addition, the problem of internal interference is further aggravated by an increase in coupling between a receiving antenna and a circuit that generates an interference component due to downsizing of the receiving device.

  As countermeasures against this problem, optimization of circuit arrangement, addition of parts (for example, a bypass capacitor, a choke coil, a filter, and a shield) for suppressing unnecessary radiation of interference components may be performed. Such optimization of circuit arrangement and addition of components lead to an increase in the design man-hour of the receiving device, an increase in cost, and an increase in size of the receiving device.

  Therefore, various techniques for suppressing internal interference have been proposed as follows.

  For example, there is a technology that includes a noise antenna that receives in-terminal noise and a transmission / reception antenna, and suppresses noise by taking a difference between a reception signal component received by the transmission / reception antenna and a noise component received by the noise antenna (for example, , See Patent Document 1).

  It also detects noise generated in the device, controls the detected noise to have the same phase and amplitude as the noise superimposed on the received signal as an interference component, and adds the controlled noise to the received signal to reduce the noise. There is a technique to suppress (for example, see Patent Document 2).

JP 2004-260428 A US Patent Application Publication No. 2006/0178157

  However, in the technique described in Patent Document 1, the element shape for detecting noise becomes large, and the terminal becomes large.

  In the technique described in Patent Document 2, a plurality of noise detection circuits corresponding to a plurality of radio systems are required in order to cancel noise of the plurality of radio systems in a portable radio terminal equipped with a plurality of radio systems. As a result, the circuit scale increases, and the number of parts constituting the circuits increases, which raises the problem of increasing the size of the terminal and increasing the number of parts.

  The present invention has been made in view of this point, and an object of the present invention is to provide a portable radio terminal that can reliably suppress internal interference without increasing the size of the terminal and increasing the number of parts.

  In order to solve the conventional problem, a portable wireless terminal according to the present invention includes a first antenna that receives a wireless signal of a first wireless system, and a second antenna that receives a wireless signal of a second wireless system. A housing, a detection unit that detects a noise component generated inside the housing, and a control unit that varies the phase of the noise component of the wireless system in which the detected phase of the noise component is to be canceled in a plurality of wireless systems A first adder that adds the received radio signal of the first radio system and the noise component whose phase is controlled; and the received radio signal and phase of the second radio system are controlled. A second adder that adds the noise component that has been output; a signal switching unit that selects to output the noise component whose phase is controlled to the first adder or the second adder; A.

  With this configuration, by performing the switching timing of the signal switching unit in a time-sharing manner, even in a plurality of wireless systems, the detection unit that detects a noise component of one system without corresponding to the plurality of wireless systems can be performed. This makes it possible to reduce the size and cost of the terminal.

  In addition, the portable wireless terminal of the present invention can be configured not to use the signal switching unit by changing the phase of a noise component of a wireless system to be canceled among a plurality of wireless systems by the control unit in a time division manner. It is.

  According to the present invention, it is possible to reliably suppress internal interference even in a plurality of wireless systems without incurring an increase in cost due to an increase in the size of a terminal and an increase in the number of parts.

1 is a block diagram showing a configuration example of a portable wireless terminal according to a first embodiment of the present invention. Timing chart showing an example of switching of the signal switching unit 501 in the portable wireless terminal according to the first embodiment of the present invention. The block diagram which shows the structural example of the portable radio | wireless terminal which concerns on the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration example of the portable wireless terminal 101 according to the first embodiment of the present invention. The mobile wireless terminal 101 includes a television reception antenna 201, a television reception amplifier unit 202, a television reception unit 203, an addition unit 204, a cellular phone antenna 301, a cellular phone reception amplifier unit 302, a cellular phone reception unit 303, and an addition unit. 304, a noise sensor 401, a noise cancellation unit 402, a signal switching unit 501, a control unit 601 for controlling the terminal, and a noise generation source 701 (generated by a circuit such as a CPU or a memory).

  The noise component in the digital television broadcast signal is a noise component 702 that is controlled to cancel the noise superimposed on the television broadcast signal with the phase and amplitude of the noise component detected by the noise cancellation unit, and the noise is superimposed. A television reception signal 703 and a television reception signal 704 with noise components canceled are shown. A similar noise component also exists in the cellular communication signal, but it is omitted in this description.

On the other hand, a noise generation source 701 exists inside the mobile wireless terminal 101, and noise components generated from the noise generation source 701 are spatially coupled to the TV reception antenna 201 and the mobile phone antenna 301. The signal is subject to noise interference, and the quality of the received signal is degraded. Therefore, a noise sensor 401 is disposed in the vicinity of the noise generation source 701, and a noise component generated from the noise generation source 701 is detected.
A digital television broadcast signal transmitted from a television broadcast station (not shown) is received by a television reception antenna 201, amplified by a television reception amplifier unit 202, and demodulated by a television reception unit 203 so that the television can be viewed. can do.

A cellular phone communication signal transmitted by a cellular phone base station (not shown) is received by a cellular phone antenna 301, amplified by a cellular phone receiving amplifier 302, and demodulated by a cellular phone receiving unit 303, so that cellular Communication can be performed.
When receiving television reception satisfactorily, the noise cancellation unit 402 controls the phase and amplitude of the detected noise component to cancel the noise 701 superimposed on the television broadcast signal (702). The signal switching unit 501 is connected to the television system side under the control of the control unit 601, and the adder 204 cancels the phase of the noise component superimposed on the television reception signal (703) and the television reception signal (703). In addition, by superimposing the noise component (702) whose amplitude has been changed, interference of the noise component is canceled (704), and it becomes possible to prevent the quality deterioration of the television signal and perform good television reception.
When receiving cellular communication satisfactorily, the noise cancellation unit 402 controls the phase and amplitude of the detected noise component to cancel the noise superimposed on the cellular signal. The signal switching unit 501 is connected to the mobile phone side under the control of the control unit 601, and the phase and amplitude are changed by the adding unit 304 so as to cancel the cellular reception signal and the noise component superimposed on the cellular reception signal. By superimposing the noise component, the interference of the noise component is canceled, and it becomes possible to prevent the quality deterioration of the cellular signal and perform good cellular communication. Note that illustration of noise components is omitted.

  FIG. 2 is a diagram illustrating an example of switching timing of the signal switching unit 501.

  In this example, an example in which the W-CDMA system is used as the mobile phone system is shown. In the standby state, the mobile phone receiving unit 303 performs an intermittent reception operation only for about 20 milliseconds in a cycle of 2.56 seconds, and does not perform a reception operation for other times. On the other hand, the television receiving unit 203 performs a continuous reception operation in the television viewing state. Therefore, the signal switching unit 501 is controlled by the control unit 601, and the output of the noise canceling unit 402 is input to the mobile phone receiving unit 303 only when the cellular communication state, that is, the mobile phone receiving unit 303 operates, and otherwise Inputs the output of the noise canceling unit 402 to the television receiving unit 203. Thereby, the noise canceling unit 402 can be used for improving the reception quality of the mobile phone during the intermittent reception operation of the mobile phone, and can be used for improving the reception quality of the television in other states. In this case, the reception quality of the television cannot be improved during the intermittent reception operation of the mobile phone, but if the time is about 20 milliseconds with a cycle of 2.56 seconds, the reception quality is sufficiently improved by the error correction function of the television signal. Since it can be maintained, there is no effect on TV viewing.

  Thus, according to the present embodiment, noise detection is performed in a time-sharing manner, so that noise can be detected by only one system of noise component detection (noise sensor 401 and noise cancellation unit 402).

  Therefore, it is possible to provide a portable wireless terminal that can reliably suppress internal interference without incurring an increase in the size of the terminal and an increase in the number of parts for a plurality of wireless systems.

(Embodiment 2)
FIG. 3 is a block diagram illustrating a configuration example of the portable wireless terminal 101 according to the second embodiment of the present invention. The signal switching unit 501 is omitted from the configuration shown in FIG. Therefore, only the difference from (Embodiment 1) will be described.

  As described with reference to FIG. 2, the cellular communication is intermittently received for about 20 milliseconds with a period of 2.56 seconds. Therefore, the noise canceling unit 402 adds the noise component whose phase and amplitude are changed so as to cancel the noise component superimposed on the cellular reception signal by the control from the control unit 601 only during the operation in which the cellular communication is intermittently received. Output to the unit 304. As described above, interference of noise components is canceled, and it becomes possible to prevent deterioration of the quality of the cellular signal and perform good cellular communication.

  When the cellular communication is not intermittently receiving, the noise canceling unit 402 adds the noise component whose phase and amplitude are changed so as to cancel the noise component superimposed on the television reception signal by the control from the control unit 601. To 204. As described above, the interference of the noise component is canceled, and it becomes possible to prevent the quality of television reception from being deteriorated and perform good television reception.

  The present invention is useful for a portable wireless terminal equipped with a plurality of wireless systems.

DESCRIPTION OF SYMBOLS 101 Mobile radio terminal 201 Television receiving antenna 202 Television receiving amplifier 203 Television receiving unit 204 Adder 301 Mobile phone antenna 302 Mobile phone receiving amplifier 303 Mobile phone receiver 304 Adder 401 Noise sensor 402 Noise canceling unit 501 Signal switching unit 601 Control unit 701 Noise source 702 Canceled controlled noise component 703 Television reception signal with superimposed noise 704 Television reception signal with noise component canceled

Claims (2)

Detecting means for detecting a noise component generated inside the portable wireless terminal;
First control means for controlling the phase of the noise component;
Switching means for connecting the noise components whose phases are controlled;
Second control means for controlling the switching means;
Adding means for adding the phase-controlled noise component to the received signal;
A portable wireless terminal. Switching connection of the noise component in accordance with a plurality of wireless systems;
The portable wireless terminal according to claim 1.

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