JPS63269898A - Electro-acoustic transducer - Google Patents

Abstract

PURPOSE:To set the maximum current capacity of a voice coil to be 1/2 and to reduce an entire coil size by disposing a coil Cn+1 in parallel to a coil Cn to which a maximum current is supplied to divide the current. CONSTITUTION:The voice coils C1-Cn corresponding to the signals of n bits inputted signals and the separated added coil Cn+1 are disposed on a bobbin 4. When the current weighted by the signals of the n bits is supplied to the voice coils C1-Cn, according to the scale of the sum of the current passing through the voice coils C1-Cn, a diaphragm is provided. At this time, on the coil Cn to which the maximum current is supplied, the coil Cn+1 is disposed in parallel, so that the current is divided into the coil Cn and the coil Cn+1, and the current capacity of the coil Cn is reduced to 1/2.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to an electroacoustic transducer directly driven by a digital signal.

(B) Prior Art In a conventional electroacoustic transducer of this type, n coils are wound around a whistle coil of a dynamic speaker so as to correspond to an n-bit digital signal. Pulses of a pulse code modulated signal are then applied to those voice coils. Pulse code modulation signals are obtained by sampling analog signals and converting them into pulses, and these pulses have a weight of up to 2'...2+1. expresses information. For example, if all pulses are O, then O
X2'+OX2"+...+OX2"=0, if all are "1", IX2'+lX2"+1×23+・
...+IX2'1, and a current flows through each voice coil correspondingly.

(c) Problems to be solved by the invention Generally, each coil of a voice coil is manufactured using conductors of the same size, but the coil corresponding to the n-th bit has one
Since a current that is twice as high as that in the coil corresponding to the bit number flows, a conductor wire for high current must be used even in the coil corresponding to the low bit number where only a low current flows, which is economically undesirable. was there.

This invention was made in consideration of these circumstances, and
The purpose is to reduce the current to the coil corresponding to the bit, thereby reducing the size of the conducting wire used for the entire voice coil to less than half.

(d) Means to solve the problem The present invention provides a method for changing the voice coil of a dynamic speaker.
In an acoustic transducer that generates sound by passing a current corresponding to an n-bit pulse code modulation signal through each of the 1st to nth voice coils, an (n+1)th coil is added to the voice coil. This acoustic transducer is characterized in that it is configured to supply a current corresponding to the n-th digit of a pulse code modulation signal to the n-th and (n+1)-th coils in parallel.

(E) The current corresponding to the signal of the maximum digit of effect is divided into the n-th coil and the added (n+1)-th coil. Therefore, the current flowing through the n-th coil becomes X, making it possible to make the current capacity of the entire coil, that is, the winding size, the same as the conventional one.

(f) Example The present invention will be described in detail below based on embodiments shown in the drawings.

Note that this invention is not limited to this.

FIG. 1 is a sectional view of a speaker showing an embodiment of the present invention. In the same figure, 1 has a center ball l in the center.
2 is a ring-shaped magnet; 3 is a ring-shaped upper plate disposed on top of the magnet 2; and support plate 1. Magnet 2.
The upper plate 3 constitutes a field section. Reference numeral 4 indicates a voice coil bobbin which is loosely fitted onto the upper part of the center ball la, 5 indicates a diaphragm whose proximal peripheral edge is connected to the upper part of the voice coil bobbin 4, and 7 indicates a distal end peripheral edge of the frame 6 and the diaphragm 5. A ring-shaped edge 8 connecting the end peripheral edge of the voice coil bobbin 4 and the frame 6 is a damper.

FIG. 2 is an explanatory diagram showing a voice coil wound around the outer periphery of the voice coil bobbin 4 shown in FIG.
. . . Cn-, , C, and a separately added coil Cnel are provided on the bobbin 4.

In such a configuration, when a current weighted by an n-bit signal is supplied to the voice coils 01 to C1, the bobbin 4 placed in the magnetic field receives a force in a direction perpendicular to the magnetic field. to vibrate the diaphragm 0 back and forth to generate air vibrations.

Therefore, since the diaphragm 5 vibrates in accordance with the magnitude of the sum of the currents flowing from the voice coil CI to the voice coil Cn, the manually inputted digital signal is directly converted into an acoustic signal. At this time, a coil On is connected in parallel to the coil co to which the largest current is supplied.
o+ is provided, and as a result, the current is shunted into the coils C0 and Cn□, so the current capacity of the coils C, , is only X. Generally, the wire size of the voice coils C1 to Crl is designed to match the maximum wire size, that is, the size of the coil C1, so that the overall wire size can be reduced to 1/2.

Table 1 shows the voltage applied to the voice coil of a speaker driven by a 4-bit signal. Conventionally, the voltage applied to the coil C1 is 1V, the coil C2 is 2V,
A voltage of 4V is applied to the coil C1 and a voltage of 8V is applied to the coil C4. In this embodiment, by setting n=4 and further adding the coil Cn*1, that is, the coil C2, the voltage applied to the coil C4 can be increased. This shows that the current voltage is half that of 4V, so the overall coil size can be reduced to 4V.

Table 1 Note that in this embodiment, the voice coil C1 of the largest digit
Although a parallel coil is added to only the voice coil Crl-1, depending on the case, a parallel coil may be further provided to the voice coil Crl-1.

(g) Effect of the invention According to this invention, the maximum current capacity of the voice coil is 17
2, reducing the overall coil size.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a partial detailed explanatory view of FIG. 1. 4...Voice coil bobbin, C3~Co...
...N-bit signal human powered voice coil, C0,...
...added voice coil. Agent Patent Attorney Shintabe Nogawa Figure 2

Claims (1)

[Claims] 1. In an electroacoustic transducer in which the voice coil of a dynamic speaker is formed of n coils and a current corresponding to an n-bit pulse code modulation signal is passed through each of the 1st to nth voice coils to generate sound, the voice coil is Furthermore (n
1. An electroacoustic transducer characterized in that a +1)th coil is added and a current corresponding to the nth digit signal of a pulse code modulation signal is supplied in parallel to the nth and (n+1)th coils.