Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JPS6019397 [0001] FIELD OF THE INVENTION The present invention relates to a speaker driving device. [Background of the invention] Generally, in small speakers and the like, the level of the low frequency component of the reproduced sound is lower than that of the other frequency components, and in order to improve this, the frequency of the reproduced sound of the speaker The low frequency included in the original signal on the side of the drive bag N (specifically, the amplifier of the original signal) that drives the speaker so that the characteristic is flat and not only in the high region but also in the low region. It has been put to practical use to provide a boost circuit for amplifying the amplitude of the component in particular. FIG. 1 is a circuit diagram showing such a conventional boost circuit. In the same figure, the circuit portion from the input terminal 1 to the output terminal 2 constitutes a low-pass boost circuit A, and such a circuit A is generally provided in front of the power amplifier 4 for driving the speaker 5. In the circuit A, 3 is an operational amplifier (operational amplifier), 6 is a variable resistor that determines the amount of boost, 7 is a capacitor, and 8 is a resistor. The turnover frequency fi at the time of low-pass boost is determined by the following equation (1). fj = concentrated-fi.degree .-. degree .- (+> where C is the capacitance of Conden 9'7, n, and the resistance value of the resistive resistor 8. When this low-pass boost circuit A is used, the frequency characteristic of the speaker drive voltage shifts from 10 to 10 in FIG. 2 (a), and ft is the turnover frequency), and the sound pressure frequency characteristic of the speaker is 9 to 9 Shift to 'to expand the frequency range of bass reproduction. However, as shown in Fig. 2 (1), when KdB low-pass boost is performed in the frequency characteristic 10 at low output with a low voltage-1-bell, it shifts as it is at high output with a high voltage level. Then, as seen in the frequency characteristic 10, KdB ′? Since the low band previously boosted reaches the saturation voltage level 11 of the power amplifier 4 earlier, and the voltage levels except the low band can not reach the voltage level beyond the margin of K dB. There is a drawback that the dynamic range is reduced by K dB. For 07-05-2019 1 example, assuming that xodI3 low-pass boost is performed, a power value at which saturation does not occur even with the use of a 100 W power amplifier is 10 W because it leaves a margin of 10 dB, which is extremely inefficient. For this reason, it is difficult to increase the low range boost amount, and the effect of expanding the frequency range of the bass reproduction is also insufficient. OBJECTS OF THE INVENTION The present invention has been made to eliminate the drawbacks in the prior art as described above, and it is therefore an object of the present invention to reduce the dynamic range of the power amplifier driving the loudspeaker. It is an object of the present invention to provide a speaker drive device capable of expanding the frequency range of bass reproduction. [Summary of the Invention] In order to achieve the above object, in a speaker driving device according to the present invention, a VCA (voltage control amplifier) involved in amplification of an input signal of a speaker driving power amplifier using a low frequency input signal level. By controlling the gain or the resistance value of the VCR (voltage control resistor), the low range boost amount can be automatically varied according to the magnitude of the input signal level. As a result, as shown in FIG. 3 (R), the frequency characteristic of the drive voltage changes from 12 to 12 and then to 12 as the voltage repe A increases, and the frequency 'IQ' l '! ? As seen in the figure, it can be concluded that what was the maximum when the low range boost amount was the frequency characteristic 12 was reduced when it was 12 and was reduced to 12 ′ ′ to only π 3. In this way, Den IJ :, level high))! There is no loss of gichum mink range even if you On the other hand, the frequency .DELTA..phi. Of the output sound pressure of the speaker at this time is 1.multidot.1, as shown in the third I * J (b), the frequency is changed from 13 to 13 'Y to 13 and so on. That is, when the output is low at low sound pressure levels, as the low-pass boost amount is large, the power of the sound pressure level-= constant area greatly expands to the low frequency area as seen in the characteristic 13. As the sound pressure level increases, the low range boost amount decreases, so that the constant region of the sound pressure level decreases as seen in the characteristic 13.13. However, even if the bass characteristics are changed in accordance with the magnitude of the power output, the loudness characteristics of the human auditory sense do not sound so unnaturally in the same ear. This is because as the sound pressure level increases, the human bass feeling further increases. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in detail with reference to the drawings. FIG. 4 is a block diagram showing an embodiment of the present invention. The circuit configuration between the input terminal 1 and the output terminal 20 is different from that of the prior art shown in FIG. 1 in the embodiment shown in FIG. Please refer to Fig.4. First, the original signal input from the input terminal 1 is divided into two paths, while the direct adder 14 is directly connected to the low pass filter (LPF) 15 and the VCA (voltage control amplifier) 16 to the other end of the adder 14. Applied to the input terminal of. That is, after low frequency components extracted from the original signal through LPFI 5 are J- 07-05-2019 2 amplified in VC′A 16, they are added to the original signal in adder 14 (corresponding to implementation of low-pass boost), and the added output is It is input to the power amplifier 4 through the output terminal 2'F. Therefore, if the gain of the VCA 16 is changed, the amount of low-pass booth will be changed. An example of the change of the low range boost amount with respect to the change of the 1 VCA 16 (7) gain when the gain in LPFI 5 is 0 rlB is as shown in FIG. In FIG. 5, as the gain to VC reaches a negative four and then to zero, and then changes to a positive value, the low-pass tooth) U gradually increases from Q dB. Will. On the other hand, the relationship between gain and control voltage {circle over (1)} input to the control input terminal k of i in VCAI 6 is as shown in FIG. 6 (a). That is, control? 511? ff。 The pressure gradually increases from a negative value of −I to −0, and thereafter reaches a positive value of + VL? It will be appreciated that the gain is linearly increasing monotonically as Qi's Ki. Return to FIG. According to the principle of the present invention, if the level (amplitude) of the original signal input to the input terminal 1 is high (and thus the output level of LPFls is high), the low range boost amount can not be reduced. The gain of VCAI 6 must be reduced (that is, reduced to the control voltage 1 input to control input terminal k). A control voltage generation circuit S shown in FIG. 4 and surrounded by a broken line is a circuit for generating a control voltage Ik3 satisfying the above relationship from the output of the LPFI5. The control voltage generation circuit S includes a rectification circuit PP117, a limiter circuit 18, an integration circuit 19, an inversion circuit 20, a level shift circuit 21. It consists of FIG. 6 (b) is a graph showing the change with respect to the input signal amplitude of each signal in the control voltage generation circuit SK of FIG. Please refer to FIG. 4 and FIG. 6 (b). The output signal {circle over (1)} of LPFI 5 is rectified by the rectifier circuit 17 and enters the integrating circuit 19 to be converted into direct current. The level shift circuit 21 shifts the level of the DC output of the integration circuit 19 in the negative voltage direction! The characteristic is as shown in straight line # 22 shown in FIG. By inputting the output of the integrating circuit 19 to the inverting circuit 20, the output characteristic of the inverting circuit 20 becomes a straight line 22 'shown in f'l 6IM (b). In order to limit the maximum boost p, the limiter circuit 18 is provided on the output side of the inverting circuit 20 to obtain the control voltage Vk of the polygonal line 22 # shown in FIG. 6 (b). Control voltage vk, VCAI 6 obtained when the level of the input a number ta in the low frequency region reaches the power amplifier saturation level 11 (see FIG. 2 (+)) by adjusting the circuit constant of each part 7 (Kane f) <-tyr, p In other words, if the voltage (-Vt,) necessary for the output to be zero is set, the power amplifier 4 can keep the margin in the dynamic range. It is a word that saturation of low frequency signal components occurs. FIG. 7 is a circuit diagram showing a specific circuit example of the embodiment shown in the block diagram of FIG. 4 and will be described in detail below. The resistor 23 and the capacitor 24 constitute a low bus ratio A. The cutoff frequency is expressed by the same equation as the equation (1). A−1pA2vA3pA4はそれぞれオペアンプ(オペレーショナル・アンブリファイア)であ る。 The operational amplifier A1 constitutes a double-wave rectifier circuit 17 together with the 07-05-2019 3 diodes 25 and 26. The operational amplifier A2 constitutes an integration circuit 19 together with a resistor 30 and a capacitor 29. The integration time constant τ is determined by the following equation (2). (1) where C1 is the capacitance of the capacitor 29, and Ri is the resistance value of the resistor 30. It is preferable that the time constant τ be a sufficiently large value so that a signal of frequency 20 Hz is integrated. The resistor 27 and the constant voltage source 28 constitute the level shift circuit 21. By applying a positive voltage to the inverting input side of the operational amplifier A2, the output of the operational amplifier A2 is level shifted in the negative voltage direction. be able to. The operational amplifier A3 constitutes the inverting circuit 20, and its gain is set to a resistance value of Q dll. The 0 diode 31 and constant voltage source 32+: L that form a resistance value are connected, and the relay P-Il path 18 is formed. The control voltage Vk is limited by the constant voltage source 32 during the control period. The operational amplifier A4 constitutes a summing circuit 14, and its resistance value is set to H so that two human powers are added to the output, for example, by the same -I + n weight I'1. Next, according to the present invention, (111 real 1 (+ r Fll y +> t! ltZ>。 FIG. 8 is a blower li9 showing another embodiment of the present invention. The embodiment shown in the figure is different from the prior art circuit shown in FIG. 1 in the circuit configuration between the input terminal] J-output insulator 2 in the following. . First, the original signal input from the input terminal 1 is divided into two paths J, one of which is applied to the low-pass boost circuit A 'and the other to the low-mass filter 15. The can open boost circuit A is obtained by changing the variable resistor 6 to the low-pass booth p ′ + l path shown in FIG. 1 by VC 几 (Ti, pressure control resistor) 33 [7. ローパスフィル タ15Jetある。 In the case of FIG. 8, the zero operation where the inverting circuit becomes unnecessary is as follows. The original signal inputted from the input terminal 1 is subjected to low-pass boost through the low-pass boost circuit A and then inputted to the power amplifier 4 through the output terminal 2. The low-pass boost amount in the circuit A can be variably controlled by VCl23. Therefore, in the control voltage generation circuit S 1, using a low-pass signal component extracted from the original signal via the LPF 15 ′, the Vci 23 is increased so that the boost Ji in the circuit person is small and low when the level is high. The control voltage Vk is generated and input to the control input terminal k. FIG. 29 is a circuit diagram showing a specific circuit example of the embodiment shown as a block diagram in FIG. 8, and the details will be described below. Similar to the operational amplifier 3 shown in FIG. 1, the low-band boost circuit 6 is configured by the capacitor 7 and the resistor 8 according to the above equation (1), and the boost amount is Is determined by the following equation (3). 几 X1 (= 1 + i··· (3) where R and x are the resistance exhibited by V CR3: ′ ′, and the ratio is the resistance of the resistor 8. FIG. 10 is a graph showing the relationship between the relative resistance value t 几 XRX (−−TL−) exhibited by VCl 33 and the low-pass boost amount A, and the relationship is represented by a curve similar to that in FIG. Be Generally, the relative resistance value RX 'exhibited by VCCa2O monotonously decreases due to the DC control voltage Vk changing from negative to positive as shown in FIG. 11 (R). Therefore, in order to control the resistance value 07-05-2019 4 representing CCa2O by the 1-bell of the low band input signal component, the AC signal as the signal component is converted to a DC signal, and the level is further shifted and then the control input terminal k Need to be applied. The mebe amplifier A1 e A2 in FIG. 9 is a portion responsible for converting an alternating current signal into a direct current signal, and performs the same operation as AI and 82 in FIG. In order to obtain a control voltage Vk indicated by the straight line 38 in FIG. 11), the DC output of the A bias A2 is level shifted in the negative voltage direction as in the case of FIG. This is the level shift circuit 21. The G-A 31 and H> voltages i 1 i 32 form a limiter circuit 18 for limiting the maximum boost amount like that of FIG. Is limited to obtain a control voltage Vk as indicated by the straight line 38 in FIG. 11 (b). Phrase in which the low-range input signal component reached the saturation repe / 1-11 of the power amplifier by adjusting the circuit rjH number of each part, the control type fI-Vk is sufficient for the relative resistance value Rno of V CIN · 33 to be 0 If the voltage (+ 'Vt,') necessary to obtain a close value is achieved, the dynamic range of the power amplifier 4 is not reduced as in the previous embodiment. The operational amplifier A5, together with the condenser 34, the capacitor 35, the resistor 36, and the resistor 37, constitutes an addip low pass filter 15 'of 12 dB10 Ct (the level decreases by 12 dB when the frequency is doubled). The cut sub frequency of the low pass filter 15 is the turnover I of the low pass boost circuit A? Each circuit constant is determined by 8σ ′ until it matches the iJ wave number. i'I ¥ 12 Figure (a) shows the speaker drive voltage when driving the speaker drive area according to the present invention (a small skier system with a cabinet volume of 1.0 / by the father i)! ・ Bell frequency characteristics, and Fig.12 (E) shows 7 frequency (1'1) of 1 speaker driving power as a parameter 7 (Q1) frequency of lid force sound pressure level from the speaker (1) 1) The characteristics shown in these figures are the power amplifier 4): When using OOW's, it is the same as the one obtained from When 'J # 1 power at the time of hearing is IW, a significant low range boost is actually achieved to achieve a significant expansion effect of the bass rrr4tE frequency range, and the maximum output (100 W), the power It can be seen from the chart that Ct can be used to reduce the dynamic range of the amplifier and to drive the speaker. [Effects of the Invention] As described above, in the present invention, in the 1-f shell f, the speaker drive device, the low-pass boost amount can be automatically varied according to the can-off input signal level. There is an effect that the reproduction frequency range can be largely expanded to the lower side without reducing the dynamic range of Further, the low-frequency characteristic realized by the present invention is sufficiently practical without being unnatural to the human ear in consideration of the loudness characteristic of the human auditory sense. [0002] Brief description of the drawings 07-05-2019 5 [0003] FIG. 1 is a circuit diagram showing an example of a boost circuit used in a conventional speaker driving device, and FIG. 2 (a) shows the frequency characteristics of the conventional speaker driving device with and without low-pass boost. The graph wE2 (b) is a graph showing poor frequency characteristics showing a drawback when the low-pass boost is carried out in the conventional speaker driving device, and FIG. 3 (a) is a graph showing the present invention. Graph showing that frequency characteristics change with voltage level, FIG. 3 (h) is also a graph showing how frequency characteristics of reproduced voice change with sound pressure level, t44 FIG. Fig. 5 is a block diagram showing an example, and Fig. 5 is a graph showing the change in the amount of low-pass booth 1 when the gain of CA1 is changed at 4.5 in the same path of Fig. 4. Figure 6 (a) is a graph showing the control voltage and the gain of the relationship in VCA16, 6 (1)) is the fourth diagram of fl + i control voltage generating times! Input signal tA of each signal at il S (graph showing relation to width with respect to width, FIG. 7 shows a concrete circuit example of the embodiment shown by the block diagram in FIG. 4 lcircuit diagram, 8 is a block diagram showing another embodiment of the present invention, FIG. 9 is a circuit diagram showing an example of a J1 curved circuit of the embodiment shown in the block diagram of FIG. 8, and FIG. 10 is FIG. Figure 11 (= 1) is a graph showing the relationship between the resistance value exhibited by VCl and 33 and the low-range goose amount of the low-range boost circuit A '. Figure 11 (= 1) is the control voltage Vk at VCCaB6 and its presentation J A graph showing the relationship of resistance, FIG. 11 (I) A graph showing the relationship of I (the control voltage applied to R 33 to the input voltage 41), FIG. 12 (a) FIG. 12 (1) is a graph showing the characteristics of the speaker drive voltage level to the frequency when the present invention is implemented. Is a graph, which also shows the frequency characteristic of output sound pressure level from Subi force. Sign Description ■ ······ input morning 1 child, 2 ...... output suburbs i Ding, 3, A1, 'A2. A: 'l) A4 + A, ..., l A6 ···························· Power-amplifier, • ·················· Speaker, 6 ··························· , 'T. 24.29, 34. 35 · · · · · · · · · · · Hunden ν, 8, 23. 27 °! 30.36, 37 ・ ・ ・ ・ ・ ・ Resistor, 9-9 t 13 t 13 p 13 · · · · · · Speaker output sound pressure characteristics, 10.10 ', 10.12 12 12. 12 · · · · · · Drive voltage characteristics 11, power amplifier saturation voltage level, adder, 15.15, low pass filter, 16. VCA (voltage control Amplifiers, 17 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 22. 22 ° 22 · · · · · · · · · · · · · · · · · · 22 · 22 · · · · · · · · · · · · · · control voltage of the VCA, 25, 26, 31 · · · · · · · · · · · · · · · · · · · · · · · · constant voltage source, 33 · · · ··· V C 電 圧 (voltage controlled resistor), A, A · · · · · · · · · low-pass circuit, 38, 8 · · · · · · VC 几 control voltage Attorney Attorney parallel tree Akira husband first view the 2vA FIG. 31 VCA glue pine (dB) rod 1 '+ ZuOsamuri OP 弯Ri圧, p-6 first 7 figure 8 figure 0 figure mho figure TrC1? 44 L 4 i E 'x' (d B) in the negative phase Fig. 11 Control 4 F mouth m1 nid figure (θ) (b) 07-05-2019 6 07-05-2019 7
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