JP2002314450A - Antenna switching device employing earphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless unit the earphone wire used in common for an antenna that can suppress noise and decrease in the reception sensitivity due to multi-path or fluctuations in the electric field strength. SOLUTION: The wireless unit is provided with a defective reception detection section 9 that detects the defective reception and an antenna switch 8 thrown to the position of either of two earphone wires 11a, 11b for its electric contact provided for stereo audio output at every detection of defective reception. On the occurrence of defective reception when the one earphone wire is used for an antenna, the other earphone wire is selected for the antenna to change the reception state of the antenna, thereby correcting the defective reception.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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. It is something.

[0002]

2. Description of the Related Art A portable radio receiver can be carried out outdoors and listened to a radio broadcast at a desired place as well as indoors. In the case of stationary radio receivers mainly used indoors, it is often equipped with a dedicated antenna to receive radio broadcasts, but in the case of portable radio receivers, the earphone attached to the main body of the radio receiver Generally, a wire is also used as an antenna.

[0003] Conventionally, among the two earphone wires prepared for outputting stereophonic sound, many have 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.

[0004]

However, when a radio receiver is used outdoors, the multipath includes a direct wave directly reaching the radio receiver and a reflected wave which is reflected and reflected by a surrounding building or a road. In addition, interference may occur between the plurality of radio waves.

When the direct wave and the reflected wave reach the radio receiver in almost the same phase, the signal level may become excessively large and appear as noise. Conversely, when the direct wave and the reflected wave reach the radio receiver with almost opposite phases, the signal levels are canceled out and become small, and the receiving sensitivity is reduced. Further, when the radio receiver is used while being moved, an extra electromotive force is generated due to electric field fluctuation, which may cause noise.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and in a wireless device using an earphone wire as an antenna, noise generation and reception sensitivity caused by multipath, electric field fluctuation, and the like occur. The purpose is to be able to suppress the decline.

[0007]

An antenna switching device using an earphone according to the present invention comprises: a failure detecting means for detecting occurrence of a reception failure in a wireless device configured to use an earphone wire as an antenna; A switch means for switching an electrical connection to one of two earphone wires provided for stereo sound output each time the occurrence of the reception failure is detected by the failure detection means; It is characterized by selectively switching earphone wires to perform spatial diversity for use as the antenna.

According to another aspect of the present invention, in a wireless device configured to use an earphone wire as an antenna, two wirelessly connected earphone wires individually provided for stereo sound output are provided. One of the two systems of audio processing means, a failure detection means for detecting the occurrence of a reception failure, and each time the failure detection means detects the occurrence of the reception failure. Switch means for switching connection, and spatial diversity for selectively switching between the two systems of audio processing means for processing is performed.

According to another aspect of the present invention, in a wireless device configured to use an earphone wire as an antenna, a high-frequency amplifier for amplifying a received high-frequency signal and a high-frequency signal output from the high-frequency amplifier are used. Intermediate frequency signal generating means for generating an intermediate frequency signal,
An intermediate frequency amplifier for amplifying the intermediate frequency signal output from the intermediate frequency signal generator, a detector for demodulating the intermediate frequency signal output from the intermediate frequency amplifier, and an amplifier for amplifying the output signal of the detector. Earphone amplifying means for outputting to the earphones, an intermediate frequency amplifying means, a failure detecting means for detecting occurrence of a reception failure using an output signal of the detection means or the earphone amplifying means, and a reception failure by the failure detecting means. Every time the occurrence of the sound is detected, the electrical connection is switched to one of the two earphone wires provided for stereo sound output, and the high-frequency signal received using any one of the switched earphone wires is transmitted to the Switch means for supplying the high-frequency amplification means.

According to another aspect of the present invention, in a wireless device configured to use an earphone wire as an antenna, a high frequency amplifying means for amplifying a received high frequency signal and a high frequency signal output from the high frequency amplifying means are used. Intermediate frequency signal generating means for generating an intermediate frequency signal,
Two systems of audio processing means including an intermediate frequency amplifying means for amplifying the intermediate frequency signal output from the intermediate frequency signal generating means, and a detecting means for demodulating the intermediate frequency signal output from the intermediate frequency amplifying means, Two earphone wires provided for stereo sound output are individually and electrically connected to the two systems of the high frequency amplifying means, and received using output signals of the intermediate frequency amplifying means or the detecting means. A failure detecting means for detecting occurrence of a failure, a switch means for switching an electrical connection to one of the two systems of audio processing means each time the occurrence of the reception failure is detected by the failure detection means, Earphone amplification 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 Characterized by comprising a stage.

Since the present invention comprises the above technical means, when one earphone wire is used as an antenna among two earphone wires prepared for outputting stereo sound, noise, reduction in reception sensitivity, and the like occur. When a reception failure occurs, switching to the other earphone wire is performed. As a result, the antenna reception condition (such as the phase relationship between the direct wave and the reflected wave) when the reception failure occurs changes, and it is possible to avoid the reception failure that has occurred.

According to another feature of the present invention, 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 changes greatly, and it is possible to more reliably avoid the occurrence of the reception failure.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) First, a first embodiment of the present invention will be described. FIG. 1 is a diagram illustrating a configuration example of a radio receiver according to a first embodiment in which an antenna switching device using an earphone according to the present invention is implemented.

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, and an earphone terminal 7. , An antenna 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 an antenna.

The mixer 2 mixes a high-frequency signal output from the RF amplifier 1 with a signal having a local oscillation frequency output from the local oscillator 3 so that the intermediate frequency (I
F) Generate a signal and output it to the IF amplifier 4 in the next stage. The local oscillator 3 generates a signal of the frequency according to 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 processed signal to a detection circuit 5 at 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 the 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 transmitted via two wires 11a and 11b provided to output left and right stereo audio. Output from earphone 12.

The earphone terminal 7 has a first connection portion 7a to which the first wire 11a is connected, and a second connection portion 7b to which the second wire 11b is connected. And
The first connection part 7a is connected to the terminal a side of the antenna switch 8 via the capacitor C1. Further, the second connection portion 7b is connected to the terminal b side of the antenna switch 8 via the capacitor C2.

As a result, the antenna switch 8 is connected to the terminal a
Side, the first earphone wire 11
a will be used as the 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 detecting section 9 detects a reception failure such as noise or a decrease in reception sensitivity caused by multipath or electric field fluctuation. Specifically, IF amplifier 4
The level of the output IF signal is constantly monitored, and when it 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.

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

Further, when the second earphone wire 11b is connected to the terminal b and the second earphone wire 11b is used as an antenna, a reception failure is detected by the reception failure detection section 9, and the failure detection signal is latched by the latch circuit 10. And the connection of the antenna switch 8 is switched to the terminal a side. This allows
Thereafter, the first earphone wire 11a is used as an antenna.

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

In particular, when a radio wave having a short wavelength such as an FM radio signal is received, switching from one earphone wire to the other earphone wire is performed, and the position of the antenna is shifted by a small distance between the left and right ears. Just moving it can change the phase relationship between the direct wave and the reflected wave,
It is possible to sufficiently avoid the occurrence of poor reception.

In the above embodiment, the occurrence of the reception failure is detected using the IF signal output from the IF amplifier 4. However, the reception failure is detected using the output signal of the detection circuit 5 or the output signal of the audio amplifier 6. The occurrence of a defect may be detected. In either case, it is possible to detect the occurrence of 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 of sound processing circuits, ie, R system.
F amplifiers 1a and 1b, mixers 2a and 2b, IF amplifier 4
a, 4b and detection circuits 5a, 5b. These functions correspond to the RF amplifier 1 described in the first embodiment,
The functions are the same as those of the mixer 2, the IF amplifier 4, and the detection circuit 5. Hereinafter, the RF amplifier 1a, the mixer 2a, the IF
The amplifier 4a and the detection circuit 5a are referred to as a first-system audio circuit, and the RF amplifier 1b, the mixer 2b, the IF amplifier 4b, and the detection circuit 5b are referred to as a second-system audio circuit.

In this embodiment, the local oscillator (OS
C) 3 is provided commonly to the two-system 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, 2b. In the present embodiment, 2
Two reception failure detection units 9a and 9b are provided for the IF amplifiers 4a and 4b of the system.

The reception failure detecting sections 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 not, and whether or not the level has dropped below the second threshold value. To detect the occurrence of reception failure due to multipath, electric field fluctuation, and the like. 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 includes reception failure detecting sections 9a, 9
b is monitored to compare the occurrence status of the reception failure, and the selection operation of the switch 22 is controlled in accordance with 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 previously selected state is maintained.

The terminal a of the switch 22 is connected to the first detection circuit 5a, and the terminal b is connected to the second detection circuit 5b. The audio amplifier 6 is connected to an output stage of the switch 22. Thus, the two-system signals output from the detection circuits 5a and 5b are
2 is selected and input to the audio amplifier 6. The audio amplifier 6 amplifies the signal input from the switch 22, and outputs the signal as a stereo audio signal.

The stereo sound 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 1a via the capacitor C1. Further, the second connection portion 7b to which the second wire 11b 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 audio circuit is used. When the switch 22 is connected to the terminal b, the second earphone wire 11b is used as an antenna, and the second audio circuit is used.

Each time the failure detection signal is supplied to the comparison circuit 21, the switch 22 switches the connection between the terminal a and the terminal b in which no reception failure has occurred (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 unit 9a, and a failure detection signal is supplied to the comparison circuit 21. When,
The connection of the switch 22 is switched to the terminal b. Thus, thereafter, the second earphone wire 11b is used as an antenna.

When the second earphone wire 11b is connected to the terminal b and the second earphone wire 11b is used as an antenna, a reception failure is detected by the second reception failure detection section 9b, and a failure detection signal is sent to the comparison circuit 21. When supplied, switch 2
The connection of 2 is switched to the terminal a side. Thereby, after that, the first earphone wire 11a is used as an antenna.

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

In this embodiment, two systems of audio circuits are prepared, and not only the antenna to be used is switched according to the occurrence of reception failure, but also the audio circuit to be used is switched, so that when reception failure occurs, Can be changed more greatly, and the occurrence of poor reception can be avoided more reliably.

In the second embodiment, the occurrence of a reception failure is detected using the IF signals output from the IF amplifiers 4a and 4b, but the reception is performed using the output signals of the detection circuits 5a and 5b. The occurrence of a defect 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.

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. It may be provided (for example, when the earphone wires 11a and 11b are wound around the main body so as to be housed). Further, in the first and second embodiments, an example in which the present invention is applied to a radio receiver has been described. However, the present invention can be applied to a wireless device other than the radio receiver.

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

[0043]

As described above, according to the present invention,
By switching to the other earphone wire when reception failure occurs when one earphone wire is used as an antenna among the two earphone wires prepared for outputting stereo sound, the other earphone wire is used. It is possible to avoid the occurrence of the reception failure by changing the antenna reception condition when the failure has occurred. As a result, in a wireless device that also uses 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.

[Brief description of the drawings]

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

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

[Explanation of symbols]

 1, 1a, 1b RF amplifier 2, 2a, 2b Mixer 3 Local oscillator 4, 4a, 4b IF amplifier 5, 5a, 5b Detection circuit 6 Audio amplifier 7 Earphone terminal 7a First connection part 7b Second connection part 8 Antenna Switch 9, 9a, 9b Reception failure detection unit 10 Latch circuit 11a First earphone wire 11b Second earphone wire 12 Earphone 21 Comparison circuit 22 Switch

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K059 CC03 DD02 DD03 DD16 DD27 EE03 5K062 AA02 AB06 AC01 AD04 AD05 AD06 AG02 BF10

Claims (4)

[Claims] In a wireless device configured to use an earphone wire as an antenna, a failure detecting means for detecting occurrence of a reception failure, and each time the occurrence of the reception failure is detected by the failure detection means, Switch means for switching an electrical connection to one of two earphone wires provided for stereo sound output, and selectively switching between the two earphone wires to perform spatial diversity for use as the antenna. An antenna switching device using an earphone, characterized in that: 2. A wireless device configured to use an earphone wire as an antenna, comprising: two systems of audio processing means individually electrically connected to two earphone wires provided for stereo sound output; A failure detecting means for detecting occurrence of a reception failure; and a switch means for switching an electrical connection to one of the two systems of 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, characterized in that spatial diversity for selectively switching between the two systems of sound processing means for processing is performed. 3. A wireless device configured to use an earphone wire as an antenna, wherein a high-frequency amplifier for amplifying a received high-frequency signal and an intermediate frequency signal are generated from the high-frequency signal output from the high-frequency amplifier. Intermediate frequency signal generating means; intermediate frequency amplifying means for amplifying the intermediate frequency signal output from the intermediate frequency signal generating means; detecting means for demodulating the intermediate frequency signal output from the intermediate frequency amplifying means; An earphone amplifying means for amplifying an output signal of the means and outputting the amplified signal to an earphone; a failure detecting means for detecting the occurrence of a reception failure using the output signal of the intermediate frequency amplifying means, the detecting means or the earphone amplifying means; Each time the occurrence of the reception failure is detected by the failure detection means, two lines provided for stereo sound output are provided. Switch means for switching an electrical connection to any one of the earphone wires and supplying a high-frequency signal received using any one of the switched earphone wires to the high-frequency amplification means. Antenna switching device. 4. A high-frequency amplifier for amplifying a received high-frequency signal, and an intermediate frequency signal generated from the high-frequency signal output from the high-frequency amplifier, in a wireless device configured to use an earphone wire as an antenna. A sound including an intermediate frequency signal generating means, an intermediate frequency amplifying means for amplifying the intermediate frequency signal output from the intermediate frequency signal generating means, and a detecting means for demodulating the intermediate frequency signal output from the intermediate frequency amplifying means Two sets of processing means are provided, and two earphone wires provided for stereo sound output are individually and electrically connected to the two sets of high frequency amplifying means, and the intermediate frequency amplifying means or the detecting means is provided. A failure detection means for detecting the occurrence of a reception failure by using the output signal of Every time the occurrence is detected, a switch for switching electrical connection to any of the two systems of sound processing means, and an output from the detection means in any of the sound processing means switched by the switch means And an earphone amplifying means for amplifying a signal to be output to the earphone.