JPH0388499A - Dynamic digital speaker - Google Patents

Abstract

PURPOSE:To simplify the constitution of a drive circuit by selecting one or two kinds of voltage value generated from the drive section. CONSTITUTION:When an input parallel PCM electric signal is inputted to a drive circuit 3, output terminals E+0-E+2 or E-0-E-2 are selected depending on the content of a signal bit B3 of voltage signal bits B0-B2. Since a bobbin 2 receives a force in response to input parallel PCM electric signals B0-B3 from a voice coil section 1, a sound pressure in response to the input parallel PCM electric signals B0-B3 is generated. Then voltage value generated from the drive section is one or two. Thus, the circuit constitution of the drive section is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrodynamic digital speaker, and particularly to improvements in its driving section.

[Prior Art] In general, a digital speaker has its electric/mechanical/acoustic system driven by the same number of DC voltage drive sources (equivalent to amplifiers) as the parallel bits of the input PCM electrical signal, and is of the electrodynamic type,
Types such as electrostatic type and piezoelectric type are known.

An example of a conventional electrodynamic digital speaker will be explained with reference to FIG. In particular, an example of an electrodynamic digital speaker with 4 pins and 1 input is shown here.

This electrodynamic digital speaker has a conical diaphragm 201
and the coil 2 provided on the bobbin 202 attached to the center.
03, and a magnetic material 204. Permanent magnet 205 and magnetic body 20
6 and a drive circuit 207. The drive circuit 207 receives 4-bit parallel PCM electrical signals B O,
B1. B2. B3 (B3 is the sign bit),
The weighting is based on the voltage So from the DC voltage source, 81. S2 (
(not shown) is input, and three voltages EO-±Boxs are weighted H corresponding to the bit size.

El -±B1 xSI B2- ±B2xS2 (positive and negative signs are B3 +, -) are output in accordance with 1°0. However, Si is a weight voltage, and in the case of B1-0, the output Ei has a high impedance (i=o, 1.
2).

These output voltages Eo, El, and B2 are generated by three separate coil portions Co, CI, and C2 provided as coils 203 on the bobbin 202 of the central yoke 206A, respectively.
A weighted current is applied to the coils C01CI and C2. Therefore, the coils Co, CI, C
2 is a magnetic material 204. t! with the cross magnetic field given by the permanent magnet 2C15! A driving force is received by the action, and this is transmitted to the diaphragm 20'l via the bobbin 202. Since the driving force is proportional to the sum of voltages, the sound pressure waveform is a 4-bit parallel PCM electrical signal B O, B 1. B2. B
The PAM sound pressure pulse train is proportional to the value indicated by 3, but the diaphragm 201 also plays the role of an acoustic low-pass filter due to its inertia, and through this acoustic low-pass filter, the sound pressure becomes a continuous sound pressure waveform and is transmitted to the space. be done.

[Problems to be Solved by the Invention] However, in the prior art, no consideration has been given to simplifying the drive unit, and the drive circuit 207 is
The configuration must be capable of generating multiple types of voltages with different signs and thicknesses depending on the code bit. Therefore, the configuration of the drive circuit becomes relatively complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel digital speaker that can solve the problems of the prior art and easily simplify the configuration of a digital speaker drive circuit. Means 1 A first form of the present invention provides a parallel pcM electric signal n bits (
n; an integer of 2 or more) is input in the form of one sign bit and n-1 voltage signal bits. For each voltage signal bit, the number of turns of each driving coil pair is set to the number of turns with an 11-digit weight corresponding to the size of the bit. 2 forming the drive coil pair above
A driving circuit is provided for selecting one of the two coils and supplying the input n-1 voltage signal bit signals to the selected coil.

A second form of the invention is a parallel PCM electrical signal n bits (
n: an integer of 2 or more) is input in the form of one sign bit and n-1 voltage signal bits, and each of the n-1 voltage signal bits has a number of turns. is provided with a driving coil that is weighted according to the size of the bit, and for the code bit, a pair of code coils that generate a magnetic field around the drive coil are provided with opposite polarities, A drive circuit is provided which causes a current to flow through each drive coil according to the data of each of the voltage signal bits, and also causes a current to flow through the corresponding code coil according to the sign of the sign bit.

[Function] The drive circuit includes parallel PCM electrical signals of n bits (n: an integer of 2 or more) BO, B1 . , Bn-1 (Bn-1 is a sign bit) is input. In the case of the first form, each of n-1 voltage signal bits B O, B 1°...
, a driving coil pair C+0 provided corresponding to Bn-2.
．． C-0; C+1. C-1;-; C+
n-2, C-n-2 is sign bit B n-1 or O is 1
Depending on the situation, one of the two coils that drive each driving coil pair is selected. For example, sign bit B
When n-1 is 1, coil C+O; C+1;...;
The group C+n-2 or the group C-0; C-1;-; C-n-2 of opposite polarity when the sign bit Bn-1 or 0 is selected, and an input signal indicating the magnitude thereof is n=-1
Each voltage signal pit BO, B1. ..., Bn-2 is input.

The above drive coil pair C+OC-0・c+i C-1-
; Number of turns of C+n-2, C-n-2 N+O, N-0;
N+1N-1;-; N+n-2, N-n-2 is
It is weighted according to the size of the pitch 1-, and N±
1=NOX2**I (No: constant; i=0.1, 2.
-, n-2; *The number indicates a power). Therefore, a driving force similar to that generated when the currents are weighted is generated in each coil, and a discrete driving force is obtained in the electric digital speaker.

What should be noted here is that the above drive circuit basically only has to perform a selection operation of selecting two output terminal groups and supplying an input signal to either side; There is no need to create and generate a signal. Therefore, the configuration of the drive circuit is extremely simplified.

Moreover, in the case of the second form, BO, B1.・, Bn-2
A drive coil Co is provided corresponding to and weighted.
, C1,-, Cn-2 are simply n-1 respective voltage signal bits BO, B1 . −． The respective drive coils Co and CI are selected according to the data 1.0 of Bn-2.

. . ., a current is simply passed through Cn-2. However, for code bit Bn-1, a pair of code coils C+ and C- are provided in opposite directions, one of which is 1.0 for code bit Bn-1. Since the magnetic field of the selected polarity is selected according to O, the magnetic field of the selected polarity is applied to the driving coils CO, C1°..., C
generated around n-2. Therefore, the same driving force as in the case where the currents are weighted is generated in each coil.

In this type of electric digital speaker, it is basically possible to select the two output terminals of the sign bit, and the output of the main voltage signal pit can be output according to the data. There is no need to create and generate. Therefore, the configuration of the drive circuit is extremely cylindrical.

[Example] A perfect example of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, 1 is a voice coil section of an electrodynamic digital speaker, 2 is a bobbin, and 3 is a drive circuit. In this electrodynamic digital speaker, as in the case shown in FIG. 2, a bobbin 2 is attached to a conical diaphragm 201, a coil of a voice coil section 1 is wound around this, and a magnetic field intersecting with this is passed through a magnetic material 2.
04. Permanent magnet 205. It is made by a magnetic circuit made of magnetic material 206. However, the structure of the voice coil section 1 wound around the bobbin 2 and the structure of the drive circuit 3 that drives it are different from those of the conventional one.

The number of bits of the input parallel PCM electrical signal input to the drive circuit 3 is BO, B1 . B2. B3 ('B3 is a sign bit) is 4 bits, but the present invention is not limited to this.

The coil section 1 receives 3 out of 4 bits of the parallel PCM electrical signal.
voltage signal bits B O, B 1. It consists of a driving coil pair 4.5°6, one for each of B2, and two coils C+O,C forming an individual driving coil pair 4.5.6. -0;C+1. C-1
; C+2. C-2 is wound around the bobbin 2 with different polarities, and the number of turns is N+O, N-0°Nki, Nki.
-1; N+2. N-2 is weighted according to the bit size, and N+! ”NOX 2 **(
NO: constant; i=o, 1, 2. -, n-2; *Sho indicates a power). For example, the coils Coo and C-0 of the drive coil pair 4 have different polarities, and their winding numbers N+O and N-0 are weighted in accordance with the size of the bit BO, that is, the power "O'".

These driving coil pairs 4, 5.6 coils Coo,
C-0; C+1. C-1; c→2. C-2 is the output terminal E+O of the drive circuit 3 as shown in FIG.
.

E-(1; E+1.E-1; E+2. 1 concubine is connected to E-2.

The selective operation of the drive circuit 3 at this time is as follows. Good on the street.

When an input parallel PCM electric signal is input to the drive circuit 3, the voltage signal bits BO, Bl, B2 are outputted to the output terminal E as follows according to the contents of the sign bit B3.
+O; E+1; E→2 or E-0; E-1゜E-
Select 2.

(1) If sign bit B3 is 1, ■Transmit to BieE+i.

(2) Make the output E-i high impedance.

(2) If sign bit B3 is O, ■Transmit B1 to E-i.

- Make output E+i high impedance.

(i=0.C2 in the above (IL (2))) According to the above, the bobbin 2 receives the input parallel PCM from the voice coil section 1.
Electrical signal B O, B 1. B2. Receives power according to B3. Therefore, the input parallel PCM electrical signal B O
, B 1. B2. Generate sound pressure according to B3. Furthermore, since only one type of voltage value is to be generated by the drive section, the configuration of the drive circuit can be simplified.

FIG. 2 shows another embodiment of the electrodynamic digital speaker. In this embodiment as well, the number of bits of the input parallel PCM electrical signal input to the drive circuit 3 is BO.

Bl, B2. B3 (B3 is a sign bit) is 4 bits, but is not limited to this.

A parallel PC is connected to the bobbin 102 attached to the conical diaphragm 101.
BO, B1.M electrical signals. The voice coil section 103 for driving is constructed by winding drive coils Co, CI, and C2 corresponding to B2, but each of these drive coils Co, CI, and C2 is single, and as shown in FIG. They are not provided in a pair as in the case of . The number of turns of each of the drive coils Co, CI, and C2 is weighted according to the bit size, and N+=NO×2**i (NO: constant; j=o+I+"', n-2," indicates a power) ) is the same as in Figure 1.

Next, the magnetic field formed around the driving voice coil section 103 is not generated by the permanent magnet 205 (FIG. 3), but by a magnetic field provided in the magnetic body 104 of the E-shaped yoke and the ball 105 in the center thereof. and a code coil 107 for drive direction control. The two drive direction control code coils 107 are composed of a pair of code coils c+C- having the same number of turns and opposite polarities.

The drive coils Co, CI, and C2 are connected to the output terminals IO, II, and I2 of the drive circuit 106, and the pair of sign coils C+ and C- for drive direction control are connected to the sign output terminals I+ and I of the drive circuit 106, respectively. – is connected to. The drive circuit 106 receives 4-bit parallel PCM electrical signals BO, Bl,
B2. Drive coil C1 (i=
o, 1.2), code coils C+, C- for drive direction control
, the respective currents I O, I 1 . I 2. I
Decide whether to flow +I- or not. At this time, the drive circuit 10
For operation 6, it is sufficient to simply control the output as follows.

(1) I 1 (i=o, 1.2) ■When B i=1, l1=1 (constant current value) ■When B1-0, l1=0.

(2) I-, I- ■When B1-1, I4 = J (constant current (fi) 3 ■-=0 ■When Bi=O, I+=0 1-=J 6 From the above, the bobbin 102 receives a driving force from the voice coil section 103 according to the parallel PCM electrical signal B O, B 1. B 2° B3.Therefore, the diaphragm 101 receives the driving force corresponding to the input parallel PCM electrical signal B O, B 1. B 2° B3. In the case of this embodiment as well, since the number of voltage values to be generated by the driving section is one or two, the circuit configuration of the driving section can be simplified.

[Effects of the Invention] As described above, according to the present invention, the number of voltage values that should be generated by the drive unit is one or two types, so the configuration of the drive circuit can be simplified.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the coil section and drive circuit section of an electrodynamic digital speaker according to an embodiment of the present invention, and FIG. 2 is a diagram showing the configuration of an electrodynamic digital speaker according to another embodiment of the present invention. , FIG. 3 is a diagram showing a conventional #electronic type digital speaker. In the figure, 1 is a voice coil section, 2 is a bobbin, 3 is a drive circuit, 4, 5.6 is a pair of drive coils, 101°201 is a conical diaphragm, 102.202 is a bobbin, 103, . 203
is a coil, 104, 204 is a magnetic material, 105 is a ball,
205 is a permanent magnet, 106.207 is a drive circuit, 107
6 indicates the code coil for drive direction control

Claims (1)

[Claims] 1. Parallel PCM electrical signal n bits (n: an integer of 2 or more)
In an electrodynamic digital speaker in which a signal is input in the form of one sign bit and n-1 voltage signal bits, a drive coil pair consisting of two coils with opposite polarities is connected to the n-1
The number of turns of each drive coil pair is weighted according to the size of the bit, and the number of turns of each drive coil pair is weighted according to the sign of the sign bit. 1. An electrodynamic digital speaker comprising: a drive circuit for selecting one of two coils forming the above-mentioned coil and supplying the input n-1 voltage signal bit signals to the selected coil. 2. Parallel PCM electrical signal n bits (n; integer greater than or equal to 2)
In an electrodynamic digital speaker, the above n is input in the form of one sign bit and n-1 voltage signal bits.
- For each voltage signal bit, a driving coil is provided whose number of turns is weighted according to the size of the bit, and for a sign bit, a pair of driving coils that generate a magnetic field around the driving coil are provided. The code coils are provided with polarities opposite to each other, and current is passed through each drive coil according to each data of the voltage signal bit, and current is passed through the corresponding code coil according to the sign of the code bit. An electrodynamic digital speaker characterized by being equipped with a drive circuit.