JPS58108879A - Earphone circuit - Google Patents

Abstract

PURPOSE:To obtain an earphone circuit which reproduces the sound of a television receiver through an earphone by composing this circuit of a loop antenna, a pickup coil which induces an audio signal in an induction magnetic field, and the earphone which operates by the sound signal amplified by an amplifier. CONSTITUTION:In a figure, 9 is the loop antenna, which is composed of a coil wound at the floopr part of a room or in a wall surface while surrounding the whole of the room in order to radiate lines of magnetic force within a range adequate for viewing the screen of the television receiver, e.g. in the whole room where the television receiver is installed. In its magnetic field, the pickup coil 1 formed by winding the coil around a core having high magnetic conductivity such as a ferrite core is placed to induce a sound output across this pickup coil 11, so this is amplified and the earphone 5 is driven to regenerate the sound from the television receiver. Namely, a sound receiver independent of the television receiver regenerates sound.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an earphone circuit that makes it possible to listen to the sound of a television receiver through earphones without directly electrically connecting the television receiver and the earphones.

Traditionally, when viewers watch television, earphones have been widely used to prevent people other than the viewers from hearing the sound coming from the television receiver, or to assist people with hearing loss. ing.

As shown in FIG. 1, the circuit of this conventional earphone consists of an audio output amplifier l, an earphone jack 2, and an earphone jack 2, which are provided inside the television receiver. Speaker 6 and TV reception gj! Earphone plaque 3 inserted into earphone jack 2 located outside the machine, and earphone cord 4. It consists of earphones 5, etc., and by inserting the earphone plug 3 into the earphone jack 2, the audio output from the television receiver's speaker 6 can be stopped, or when used together with the speaker 6, the audio can be output to the earphone 5. The earphones 5 were inserted into the ear canal to listen to the audio from the television receiver.

However, in the conventional earphone circuit, the earphone plug 3 must be inserted into the earphone jack 2 to make an electrical connection, so if the earphone cord 4 is short, the screen will be forced to move closer to the television receiver. Since the roughness of the earphone cord was noticeable and not good for the 4th ear, I had to make the earphone cord 4Ifi longer than a certain amount. For this reason, the long earphone cord 4 was a nuisance and was easily tangled. In addition, it is difficult to remove the earphones (and move your body), and when you use the earphones and move your body at 7'C, the earphone cord 4 is pulled and often breaks, which is a major drawback. there were.

In view of the above-mentioned drawbacks, the present invention has been developed to
A loop antenna that forms an induced magnetic field in a range suitable for viewing the A side, a pickup coil that enters the induced magnetic field and induces an audio signal, and an earphone that operates by transmitting the audio signal to the audio signal amplified by an amplifier. Accordingly, the sound from the television receiver can be played back through the earphones without making direct electrical contact between the television receiver and the earphones, and without using a complicated and expensive method such as a wireless method. It can be used as an earphone circuit for various purposes.

The present invention will be explained in detail below.

First, if we clarify the principle of the present invention, it is possible to obtain an audio output of at least I KW or more using a final wave amplifier in the audio output section (circuit) of a television receiver.
This output is used to form an induced magnetic field within a certain range, and a pick-up coil is placed within the induced magnetic field to induce a weak audio signal.This signal is amplified and the earphone is activated to listen to the television program. This allows audio to be played back.

Next, the present invention will be explained in detail based on FIGS. 1, 2, and 3. A 3-pin plug, not shown, can be inserted into the jack 2 connected to the audio output amplifier 1 similar to that shown in FIG. It is set in. 7 is a step-down transformer for impedance conversion, and is a tap for 8Fi impedance matching.

Reference numeral 9 is a loop antenna, which is placed on the floor of the room or on a mural in order to radiate magnetic lines of force over a range suitable for viewing the screen of a television receiver, for example, the entire room where the television receiver is placed. It is formed from a coil wound around it.

4ri impedance matching tap 8 and loop antenna 9! l! This is the following code.

10Fi shows an audio receiver as a whole, and includes a pickup coil 11 for obtaining an electromotive force from lines of magnetic force radiated from a loop antenna 9 by winding a coil around a ferrite core;
It consists of an audio amplifier 12 with a high input impedance whose gain can be manually changed by t b , a battery 13 for powering the audio amplifier 12, and an earphone 5 connected to the audio amplifier 12. Furthermore, these devices are compact and integrally formed, making them portable by putting them in a bag, pocket, or the like. In addition, the output impedance of the audio amplification*i of television receivers is often set to 8Ω to match the impedance of the speaker, and #cFi, which performs impedance matching with the loop antenna 9, can easily increase the number of turns of the loop antenna 90. However, in a four-shot BA, it is desirable to create a loop antenna according to the structure of the room, so the number of turns Fi can only be expected to be from 1 to 10 times, but the impedance of such a loop antenna cannot be expected to exceed 10 even at 1000Hz. For this reason, the impedance of the actually created loop antenna is calculated or adjusted, and then the transformer 7 is used and the MEP 8 for impedance matching is made of ceramic to supply the maximum audio power to the loop antenna 9.

In this way, it is possible to obtain the magnetic field generated by the audio power in the room that is the television receiver, but in this magnetic field there is a magnetic field made of a material with high magnetic permeability, such as a ferrite core. When the coil 11 is placed, an audio output is generated from the pickup coil 11, and this is amplified to drive the earphone 5 and reproduce the audio from the television receiver. In other words, television reception gkm
The sound can be reproduced by a separate audio receiver.

It should be noted that the strength of the magnetic field also occurs in the room where the loop antenna 9 is installed, but in this case, a glance can be done as follows.

For the sake of explanation, assuming that the loop antenna is circular, the strength of the magnetic field due to the loop antenna 9 is inversely proportional to the distance from the antenna line, so the magnetic field is weakest at the center of the loop antenna 9.

Furthermore, if the position of the pickup coil 11 deviates from the plane including the loop antenna, the magnetic field will be reduced by 11. If the number of turns of the pickup coil 11 and the gain of the audio amplifier 12 are selected so that the earphones can be moved sufficiently even in such a position, the earphones will be activated when the pickup coil 11 leaves this lowest magnetic field point. The audio output from 5 will increase. When listening to sound through earphones 5Vr, television viewers use the loop antenna 9.
It is unknown where on the surface surrounded by
Since this is unlikely, the gain of the acoustic amplifier 12 may be adjusted and fixed so that the volume is easy to hear at a fixed position.

Fig. 3 shows an example of a loop antenna consisting of a spider coil that makes it possible to obtain an equal magnetic field within the viewable range of a single television receiver. Since an equal magnetic field can be obtained anywhere on the surface of the loop antenna, it is useful for viewers who move around a lot. However, in this case, since the loop antenna forms a surface, it must be installed on the floor of the room or under the floor.

As described above, according to the present invention, there is no need to electrically connect the television receiver and the earphones directly, and the earphone circuit itself is carried around by the viewer, so there is no need to pull the cord when the viewer moves. (Earphone breakage problems almost never occur. Also, since the earphones are not extended long into the room, there are no problems with tangled cords or tripping over coats, and the earphones are always connected.) When used for elderly people who need it, its effects are remarkable.

Furthermore, since the present invention does not use radio waves, etc., the circuit configuration is simple and inexpensive, and there is no risk of radio wave interference to other wireless devices. This has the advantage that there is no need for any operation to tune to a specific frequency.

[Brief explanation of drawings]

$1111 shows a conventional television receiver*IIK earphone circuit, FIG. 2 shows an earphone circuit for a television receiver 11K according to the present invention, and FIG. 3 shows another embodiment of the loop antenna according to the present invention. 2...Television receiver earphone jack 3.
... Plug 5 ... Earphone 9 ... Loop antenna 10 ... Audio receiver 11 ... Pickup coil Applicant NEC Corporation

Claims (1)

[Claims] A loop antenna connected to the audio output section of the television receiver is arranged in a range suitable for viewing one side of the television receiver to form a guided magnetic field, and a pickup coil is provided within the guided magnetic field. An earphone circuit characterized in that the audio of the television receiver can be heard through the earphones by generating an audio signal and amplifying the wrinkled audio signal with an amplifier to operate the earphones.