JPH0213403B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an audio cable cord, and is applicable to all fields dealing with the transmission of audio frequency signals. At least two conductive paths for transmitting audio signals are usually filled with flexible holding bodies such as vinyl chloride or polyethylene and held substantially parallel or concentrically. This is because it is believed that a considerable degree of insulation resistance is required between conductive paths. It is known that in this type of cable cord, the solid holder is charged by the signal current, causing noise. was provided with an antistatic coating. However, when the holder is made of polyethylene, the addition of an antistatic agent makes it difficult to form the holder into a thin solid body with no gaps between the holder and the conductor. Furthermore, in the case of a vinyl chloride holder, there is a lot of noise due to the inherent properties of the material, so there is no point in mixing an antistatic agent. Formation of an antistatic coating increases the outer diameter of the cable cord and cannot meet the demand for miniaturization. The present invention has been made based on the above-mentioned circumstances, and it is an object of the present invention to provide an audio cable cord that has less noise and can be made smaller if necessary. To achieve this objective, according to the invention:
A cord having a plurality of conductive paths held by a flexible solid holder for transmitting audio frequency signals, wherein the solid holder includes a conductive material. More specifically, the insulation resistance of the solid holder is about two orders of magnitude larger than the internal resistance of the connected device;
Generally, it should be around 1MΩ. Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a so-called coaxial cable, in which a central conductor 10 is covered with an insulating material 11 of vinyl chloride or polyethylene, and a mesh-like conductor 12 surrounds the outside. If necessary, cover the outside of the conductor 12 with a vinyl or rubber insulating material 13.
Cover with According to this embodiment, a predetermined amount of carbon was mixed into the insulating material 11 made of vinyl chloride or polyethylene. When we calculate the ratio of noise current and noise voltage to a conventional cord with a resistance value of 100MΩ per unit length, we find that the insulation resistance is 10KΩ/m, 100KΩ/m,
The following table shows each code of 1MΩ/m.

[Table] The above results are a comparison of the noise current and noise voltage generated when a cord with the same outer diameter is struck under the same conditions. In addition, for each code from No. 1 to No. 3, the volume percentage for vinyl chloride is 12 to 13% and 9, respectively.
-10% and 6-7% of carbon is mixed. As can be seen from this, the insulation resistance decreases as the amount of carbon increases, and in general, it is sufficient to have an insulation resistance that is about two orders of magnitude higher than the internal resistance of the device to be connected. For example, the internal resistance of a typical microphone is at most 1KΩ,
Assuming that the electromotive force is about 0.1V, I=0.1(V)/1
(KΩ) = 10 ^-4 (A), and since it is a small current, it is 1M, which is about two orders of magnitude larger than the internal resistance of the amplifier side, which is 10KΩ.
It can be seen that the insulation resistance should be approximately Ω. FIG. 2 shows a cord in which two conductors 21 and 22 are held in parallel by an insulating material 20, and in this case as well, a desired amount of carbon is mixed into the insulating material 20. Figure 3 shows four conductors 31, 32, 33, and 34 covered with insulating materials 35, 36, 37, and 38, respectively, which are combined into one cord with aggregate material 39. A desired amount of carbon is mixed into the insulating materials 35-38. In addition, aggregate material 39
Carbon may be mixed in. By configuring this invention as described above,
It is possible to provide an audio cable cord that has less noise and can be made smaller if necessary.

[Brief explanation of drawings]

1 to 3 are configuration diagrams according to an embodiment of the present invention. 10, 12, 21, 22, 31, 32, 33,
34...Conductor, 11, 20, 35, 36, 37,
38...Insulating material.

Claims (1)

[Claims] 1. An audio cable in which a plurality of conductive paths are held by a flexible solid holder for transmitting audio frequency signals, the solid holder containing a conductive material. code. 2. The audio cable cord according to claim 1, wherein the insulation resistance of the solid holder is about two digits larger than the internal resistance of the connected device.