WO2002087109A1

WO2002087109A1 - Antenna switching apparatus using earphone

Info

Publication number: WO2002087109A1
Application number: PCT/JP2002/003618
Authority: WO
Inventors: Takeshi Ikeda; Hiroshi Miyagi
Original assignee: Niigata Seimitsu Co., Ltd.
Priority date: 2001-04-16
Filing date: 2002-04-11
Publication date: 2002-10-31
Also published as: TW561728B; JP2002314450A

Abstract

An antenna switching apparatus comprises a reception failure detection block (9) for detecting generation of reception failure and an antenna switch (8) for switching electrical connection to one of two earphone wires (11a, 11b) provided for outputting a stereo sound each time generation of reception failure is detected. When a reception failure is generated while utilizing one of the earphone wires as an antenna, switching to the other earphone wire is performed, so that an antenna reception state when the reception failure is generated is changed, thereby evading the reception failure.

Description

Description Antenna switching device using earphones

The present invention relates to an antenna switching device using an earphone, and is suitable for use in, for example, a device in which a wire of an earphone attached to a wireless device such as a radio receiver also serves as an antenna. . Background art

Portable radio receivers can be taken outdoors as well as indoors to listen to radio broadcasts at desired locations. In the case of stationary radio receivers mainly used indoors, dedicated antennas are often provided to receive radio broadcasts.However, portable radio receivers have earphones attached to the radio receiver itself. Generally, a wire is also used as an antenna.

In the past, many of the two earphone wires prepared for outputting stereo sound used only one wire as an antenna. In some, both earphone wires were connected via a choke coil and two earphone wires were used as antennas.

However, if a radio receiver is used outdoors, the multipath including the direct waves that reach the radio receiver directly and the reflected waves that are reflected by surrounding buildings and roads, etc., may cause the interference between these multiple radio waves. May interfere with each other.

If the direct wave and the reflected wave reach the radio receiver in almost the same phase, the signal level may become too large and noise may appear. vice versa However, when the direct wave and the reflected wave reach the radio receiver in almost opposite phases, the signal levels are canceled out and become small, and the receiving sensitivity is reduced. In addition, when the radio receiver was used while moving, an extra electromotive force was generated due to electric field fluctuations, which sometimes caused noise.

The present invention has been made in order to solve such a problem, and in a wireless device that uses an earphone wire as an antenna, the generation of noise due to multipath electric field fluctuations and the like, and the reception sensitivity are reduced. The purpose is to be able to suppress the decline. Disclosure of the invention

An antenna switching device using an earphone according to the present invention is a wireless device configured to use an earphone wire as an antenna, comprising: a failure detection unit configured to detect occurrence of a reception failure; A switch means for switching an electrical connection to one of two earphone wires provided for stereo sound output every time occurrence of a defect is detected, and selectively switching the two earphone wires. In this case, spatial diversity used as the antenna is performed. According to another aspect of the present invention, in a wireless device configured to use an earphone wire as an antenna, two audio systems that are individually electrically connected to two earphone wires provided for stereo audio output. Processing means; a failure detection means for detecting the occurrence of a reception failure; and an electrical connection to one of the two audio processing means each time the occurrence of the reception failure is detected by the failure detection means. A switch means for switching, wherein spatial diversity for selectively switching between the two systems of sound processing means for processing is performed.

In another aspect of the invention, an earphone wire is used as an antenna. A high-frequency amplifier for amplifying a received high-frequency signal; an intermediate-frequency signal generator for generating an intermediate-frequency signal from a high-frequency signal output from the high-frequency amplifier; Intermediate frequency amplifying means for amplifying the intermediate frequency signal output from the frequency signal generating means, detecting means for demodulating the intermediate frequency signal output from the intermediate frequency amplifying means, and amplifying the output signal of the detecting means Earphone amplifying means for outputting to the earphones, an intermediate frequency amplifying means, a failure detecting means for detecting occurrence of a reception failure by using an output signal of the detecting means or the earphone amplifying means, and the failure detecting means. Each time the occurrence of the reception failure is detected, the electrical connection to one of the two earphone wires provided for stereo sound output is disconnected. Instead, a high-frequency signal received using either earphone wire has been switched, characterized in that a switch means for supplying said high frequency amplifying means.

According to another aspect of the present invention, in a wireless device configured to use an earphone wire as an antenna, high-frequency amplifying means for amplifying a received high-frequency signal, Intermediate frequency signal generating means for generating an intermediate frequency signal; intermediate frequency amplifying means for amplifying the intermediate frequency signal output from the intermediate frequency signal generating means; and demodulating the intermediate frequency signal output from the intermediate frequency amplifying means. And two earphone wires provided for stereo audio output are individually and electrically connected to the two high-frequency amplifiers, respectively. Failure detection means for detecting the occurrence of reception failure using the output signal of the intermediate frequency amplification means or the detection means; By every occurrence of the reception failure is detected, a switching means for switching the electrical connection to one of the audio processing means of the upper Symbol two systems, one of the voice processing means is switched by said switching means And an earphone amplifying means for amplifying a signal output from the detection means in the above and outputting the amplified signal to an earphone.

Since the present invention includes the above technical means, when one of the two earphone wires prepared for outputting stereo sound is used as an antenna, noise or a decrease in reception sensitivity may occur. If a reception failure occurs, switching to the other earphone wire is performed. As a result, the receiving condition of the antenna (such as the phase relationship between the direct wave and the reflected wave) when the reception failure occurs changes, and the generated reception failure can be avoided. According to this, two systems of audio processing means are provided, and not only the antenna to be used is switched according to the occurrence of reception failure, but also the audio processing means to be used is switched. As a result, the reception situation when a reception failure occurs greatly changes, and the occurrence of the reception failure can be more reliably avoided. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing a configuration example of a radio receiver according to a first embodiment, which implements an antenna switching device using an earphone according to the present invention.

FIG. 2 is a diagram illustrating a configuration example of a radio receiver according to a second embodiment in which the antenna switching device using the earphone according to the present invention is implemented. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(First Embodiment)

First, a first embodiment of the present invention will be described.

FIG. 1 shows an antenna switching device using an earphone according to the present invention. FIG. 2 is a diagram showing a configuration example of a radio receiver according to the first embodiment.

As shown in FIG. 1, the radio receiver according to the first embodiment includes an RF amplifier 1, a mixer 2, a local oscillator (OSC) 3, an IF amplifier 4, a detection circuit 5, an audio amplifier 6, an earphone terminal 7, an antenna It has a switch 8, a reception failure detection unit 9, and a latch circuit 10.

The RF amplifier 1 receives a radio signal (high-frequency signal) in the FM or AM broadcast wave band via an antenna and an antenna switch 8, and amplifies the signal. In the present embodiment, the wires 11a and 11b of the earphone 12 connected to the earphone terminal 7 are also used as antennas. The mixer 2 generates an intermediate frequency (IF) signal by mixing the high-frequency signal output from the RF amplifier 1 and the signal of the local oscillation frequency output from the local oscillator 3, and supplies the intermediate-frequency (IF) signal to the IF amplifier 4 in the next stage. Output. The local oscillator 3 generates a signal of the frequency in accordance with a local oscillation frequency controlled by a PLL (Phase Locked Loop) circuit (not shown) according to the set desired reception frequency and supplies the signal to the mixer 2. .

The IF amplifier 4 performs predetermined processing such as amplification on the IF signal output from the mixer 2 and outputs the result to the detection circuit 5 in the next stage. The detection circuit 5 detects the IF signal output from the IF amplifier 4 and outputs the result to the audio amplifier 6. The audio amplifier 6 amplifies the detection output from the detection circuit 5 and outputs it as a stereo audio signal.

The stereo audio signal output from audio amplifier 6 is output from a speaker (not shown). When the earphone 12 is connected to the earphone terminal 7, the stereo audio signal output from the audio amplifier 6 is divided into two wires 11a, 1a provided to output left and right stereo audio. Output from earphone 12 via 1 b.

The earphone terminal 7 is connected to the first connection portion 7 to which the first wire 11a is connected. a and a second connection portion 7b to which 1 lb of the second wire is connected. The first connection part 7a is connected to the terminal a side of the antenna switch 8 via the capacitor C1. Also, the second connection portion 7b is connected to the terminal b side of the antenna switch 8 via the capacitor C2. Thus, when the antenna switch 8 is connected to the terminal a side, The earphone wire 11a will be used as an antenna. When the antenna switch 8 is connected to the terminal b, the second earphone wire 11b is used as an antenna.

The reception failure detection unit 9 detects a reception failure such as noise or a decrease in reception sensitivity caused by multipath, electric field fluctuation, and the like. Specifically, the level of the IF signal output from the IF amplifier 4 is constantly monitored, and when the level exceeds the first threshold value, it is determined that noise has occurred. Also, it is determined that the receiving sensitivity has decreased when the value becomes smaller than the second threshold value. When such a reception failure is detected, the latch circuit 10 is activated to latch a failure detection signal.

The antenna switch 8 alternately switches the connection between the terminal a side and the terminal b side every time a failure detection signal is latched on the latch circuit 10. That is, when the first earphone wire 11a is connected to the terminal a and the first earphone wire 11a is used as an antenna, a reception failure is detected by the reception failure detection unit 9, and the failure detection signal is latched by the latch circuit 10. Then, the connection of the antenna switch 8 is switched to the terminal b. Thus, thereafter, the second earphone wire 11b is used as an antenna.

Also, when a reception failure is detected by the reception failure detection unit 9 when the second earphone wire 1 lb is used as an antenna connected to the terminal b side and a failure detection signal is latched by the latch circuit 10, , Antenna switch Connection of 8 is switched to terminal a side. Thus, thereafter, the first earphone wire 11a is used as an antenna.

As described above, in the present embodiment, when one of the two earphone wires 11a and 11b provided for outputting stereo sound is used as one antenna, When a poor reception occurs, the other wire is used and used as an antenna. This makes it possible to change the reception situation when a reception failure occurs by switching the antenna to be used, and to immediately avoid the occurrence of the reception failure.

In particular, when receiving a radio wave with a short wavelength such as an FM radio signal, switch from one earphone wire to the other earphone wire and move the antenna position only a short distance between the left and right ears However, it is possible to change the phase relationship between the direct wave and the reflected wave, and it is possible to sufficiently avoid the poor reception that has occurred.

In the above-described embodiment, the occurrence of reception failure is detected using the IF signal output from the IF amplifier 4, but the occurrence of reception failure is detected using the output signal of the detection circuit 5 or the output signal of the audio amplifier 6. May be detected. In any case, it is possible to detect the occurrence of a reception failure by comparing a predetermined threshold value appropriately determined with the level of a signal that is constantly monitored.

(Second embodiment)

Next, a second embodiment of the present invention will be described.

FIG. 2 is a diagram illustrating a configuration example of a radio receiver according to a second embodiment in which the antenna switching device using the earphone according to the present invention is implemented.

As shown in FIG. 2, the radio receiver according to the second embodiment has two systems. Audio processing circuit, that is, RF amplifier la, lb, mixer 2a, 2b,

It has 1F amplifiers 4a and 4b and detection circuits 5a and 5b. These functions are the same as the functions of the RF amplifier 1, the mixer 2, the IF amplifier 4, and the detection circuit 5 described in the first embodiment. In the following, the RF amplifier 1a, mixer 2a, IF amplifier 4a and detection circuit 5a are referred to as the first audio circuit, RF amplifier lb, mixer 2b, IF amplifier 4b and detection circuit 5b are referred to as These are called two-system audio circuits.

In the present embodiment, the local oscillator (OSC) 3 is provided commonly to the two mixers 2a and 2b. That is, the local oscillator 3 generates a signal of the set desired reception frequency, and outputs the signal to the two mixers 2 a,

Feed 2b. In the present embodiment, two reception failure detection units 9a and 9b are provided for the two systems of IF amplifiers 4a and 4b.

The reception failure detectors 9a and 9b determine whether the level of the IF signal output from the corresponding IF amplifier 4a or 4b has exceeded the first threshold value or whether the level has dropped below the second threshold value. By monitoring whether or not it is possible to detect the occurrence of reception failure due to multipath or electric field fluctuations. When it is detected that a reception failure has occurred, a failure detection signal is supplied to the comparison circuit 21. The comparison circuit 21 monitors the reception failure detecting sections 9a and 9b to compare the occurrence state of the reception failure, and controls the selection operation of the switch 22 according to the result. That is, the switch 22 is controlled so as to select the audio circuit of the system in which the reception failure has not occurred. If no reception failure has occurred in any of the systems, the previous selection state is maintained.

The terminal a side of the switch 22 is connected to the first detection circuit 5a, and the terminal b side is connected to the second detection circuit 5b. An audio amplifier 6 is connected to an output stage of the switch 22. As a result, one of the two signals output from the detection circuits 5a and 5b can be selected using switch 22. And input to the audio amplifier 6. The audio amplifier 6 amplifies the signal input from the switch 22 and outputs it as a stereo audio signal.

The stereo audio signal output from the audio amplifier 6 is output from the earphone 12 via, for example, the earphone terminal 7 via the two wires 11a and 11b. In the earphone terminal 7, the first connection portion 7a to which the first wire 11a is connected is connected to the first RF amplifier la via the capacitor C1. Further, the second connection portion 7b to which the second wire lib is connected is connected to the second RF amplifier 1b via the capacitor C2.

Thus, when the switch 22 is connected to the terminal a, the first earphone wire 11a is used as an antenna and the first system audio circuit is used. When the switch 22 is connected to the terminal b, the second earphone wire 1 lb is used as an antenna and the second audio circuit is used.

The switch 22 switches the connection between the terminal a and the terminal b, whichever has no reception failure, every time the failure detection signal is supplied to the comparison circuit 21 (may be maintained as it is). That is, when the first earphone wire 11a is connected to the terminal a and the first earphone wire 11a is used as an antenna, a reception failure is detected by the first reception failure detection section 9a, and the failure detection signal is compared with the comparison circuit 2 When supplied to 1, the connection of switch 22 is switched to terminal b. Thus, thereafter, the second earphone wire l ib is used as an antenna.

When 1 lb of the second earphone wire is used as an antenna connected to the terminal b, reception failure is detected by the second reception failure detection unit 9 b. When the signal is detected and the failure detection signal is supplied to the comparison circuit 21, the connection of the switch 22 is switched to the terminal a. Thus, thereafter, the first earphone wire 11a is used as an antenna.

As described above, also in the second embodiment, the left and right two earphone wires 11a and 11b provided for outputting stereo sound are used, and one of the wires is used as an antenna. If a reception failure occurs while switching, the other wire is used and used as an antenna. This makes it possible to change the reception situation when a reception failure occurs by switching the antenna to be used, and to immediately avoid the occurrence of the reception failure.

Further, in the present embodiment, two audio circuits are prepared, and not only the antenna to be used is switched according to the occurrence of the reception failure, but also the audio circuit to be used is switched, so that when the reception failure occurs, The reception condition can be changed more greatly, and the generated reception failure can be avoided more reliably.

In the second embodiment, the occurrence of reception failure is detected using the IF signals output from the IF amplifiers 4a and 4b, but the output signals of the detection circuits 5a and 5b are used. The occurrence of reception failure may be detected. Also in this case, it is possible to detect the occurrence of reception failure by monitoring a predetermined threshold value and signal level appropriately determined. .

Also, in the first and second embodiments, the earphone 12 is configured to be detachable from the radio receiver main body via the earphone terminal 7, but the earphone 12 is integrated with the radio receiver main body. (For example, when the earphone wire 11a, 1lb is wound inside the main unit so that it can be stored).

In the first and second embodiments, the present invention is applied to a radio receiver. Although an example of application has been described, the invention can also be applied to wireless devices other than a radio receiver.

In addition, each of the embodiments described above is merely an example of a concrete example in carrying out the present invention, and the technical scope of the present invention should not be interpreted in a limited manner. is there. That is, the present invention can be implemented in various forms without departing from the spirit or the main features thereof.

As described above, according to the present invention, when a reception failure occurs when one of the two earphone wires is used as an antenna, the other of the two earphone wires prepared for outputting a stereo sound is used. By switching to the earphone wire, it is possible to change the antenna reception situation when a reception failure has occurred, and to avoid the occurrence of the reception failure. As a result, in a wireless device using the earphone wire as an antenna, it is possible to suppress the occurrence of noise and a decrease in reception sensitivity due to multipath and electric field fluctuation. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is useful in a wireless device that also uses an earphone wire as an antenna, in which it is possible to suppress generation of noise and a decrease in reception sensitivity due to multipath and electric field fluctuation.

Claims

The scope of the claims

1. In wireless devices designed to use earphone wires as antennas,

Failure detection means for detecting occurrence of reception failure;

Switch means for switching an electrical connection to one of two earphone wires provided for stereo sound output every time the occurrence of the reception failure is detected by the failure detection means,

An antenna switching device using earphones, wherein the two earphone wires are selectively switched to perform spatial diversity for use as the antenna.

2. In wireless devices designed to use earphone wires as antennas,

Two systems of audio processing means electrically connected to two earphone wires provided for stereo audio output, respectively,

Failure detection means for detecting occurrence of reception failure;

A switch means for switching an electrical connection to one of the two audio processing means each time the occurrence of the reception failure is detected by the failure detection means,

An antenna switching device using an earphone, wherein spatial diversity for performing processing by selectively switching between the two systems of audio processing means is performed.

3. In a wireless device designed to use the earphone wire as an antenna,

High-frequency amplification means for amplifying the received high-frequency signal,

From the high-frequency signal output from the high-frequency amplification means, Means for generating an intermediate frequency signal,

Intermediate frequency amplification means for amplifying the intermediate frequency signal output from the intermediate frequency signal generation means,

Detection means for demodulating the intermediate frequency signal output from the intermediate frequency amplification means;

Earphone amplification means for amplifying the output signal of the detection means and outputting the amplified signal to an earphone;

A failure detection means for detecting the occurrence of a reception failure by using the output signal of the intermediate frequency amplification means, the detection means or the earphone amplification means; and a step each time the failure detection means detects the occurrence of the reception failure. Switch means for switching the electrical connection to one of the two earphone wires provided for Leo audio output, and supplying a high-frequency signal received using the switched one of the earphone wires to the high-frequency amplifier means; An antenna switching device using an earphone, comprising:

4. In a wireless device designed to use the earphone wire as an antenna,

High-frequency amplification means for amplifying the received high-frequency signal; intermediate-frequency signal generation means for generating an intermediate-frequency signal from the high-frequency signal output from the high-frequency amplification means; and intermediate frequency output from the intermediate-frequency signal generation means Two systems including audio processing means including an intermediate frequency amplifying means for amplifying a signal and a detecting means for demodulating the intermediate frequency signal output from the intermediate frequency amplifying means, two of which are provided for stereo audio output A failure detecting means for electrically connecting earphone wires to the two high-frequency amplifying means individually and detecting occurrence of reception failure using an output signal of the intermediate frequency amplifying means or the detecting means; Each time the occurrence of the reception failure is detected by the failure detection means, a switch means for switching an electrical connection to one of the two audio processing means;

An earphone amplifying means for amplifying a signal output from the detection means in any of the sound processing means switched by the switch means and outputting the amplified signal to an earphone. Switching device.