JP3562175B2 - Bass enhancement circuit - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to bass reproduction of sound reproduction. In particular, the present invention relates to bass reproduction of a TV set with poor bass reproduction.
[0002]
[Prior art]
The speakers mounted on the TV set cannot reproduce sufficient bass components due to size and shape restrictions, and despite the broadcasting of digital high-performance music sources such as BS (Satellite Broadcasting) and Hi-Vision, There was a problem that only poor bass reproduction could be enjoyed. In recent years, the number of occasions of connection with external source devices such as CDs and LDs has increased, and the need for bass reproduction has been desired. Normally, the bass can be enhanced by boosting the bass with a tone control circuit (tone control). However, this tone control circuit is often implemented as an IC, and the dynamic range from the power supply used by the IC is usually increased. Decided, naturally the amount of boost will be limited. In order to compensate for this drawback, as disclosed in Japanese Utility Model Laid-Open No. 4-112599, a sound reproducing method for adding and amplifying only the low frequency component of the audio LR signal at the stage preceding the power amplifier, adding the result to the respective LR signals, and enhancing the low frequency. It has been known. Hereinafter, an example of bass enhancement will be described with reference to FIG.
[0003]
In FIG. 4, reference numeral 10 denotes a filter block composed of an LPF for extracting a bass component and an HPF for extracting a treble component, 11 an adder for adding only the bass component of the audio LR signal, and 12 amplifying the signal level. An amplifier 13 is an adder that adds the amplified bass component to a treble component of the input audio LR signal, 14 is a power amplifier that amplifies power, and 15 is a speaker.
[0004]
The operation of the bass enhancement configured as described above will be described. The input audio LR signal is separated into a low frequency component and a high frequency component by the filter block 10, and only the low frequency component is added by the adder 11. The added bass component is amplified by the amplifier 12 in accordance with the effect, and is added to the treble component of the audio LR signal through the adder 13, respectively. The audio signal of the entire band in which the bass is enhanced is power-amplified by the power amplifier 14. Is reproduced from the speaker 15.
[0005]
[Problems to be solved by the invention]
However, the above-described conventional configuration is the same as the bass enhancement of the tone control, and can be solved by increasing the boost amount of the tone control. The power supply of the IC and the method of expanding the dynamic range may be considered. However, although there is an effect of enhancing the bass, the burden on the power amplifier increases in all cases. That is, the bass signal applied to the power amplifier becomes large, and a heat generation problem of the power amplifier occurs. The power amplifier used in the TV set has only an output of about 10 W, and there is a concern that the power amplifier may be damaged by heat. In addition, since the bass is constantly boosted, there is a problem that the bass becomes a rough low tone, the sound becomes muffled, and the sound becomes indistinct and hard to hear.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, the bass enhancement circuit of the present invention is characterized in that by enhancing and reproducing the bass signal level only at the rising part of the bass, the bass is enhanced, and the bass is enhanced with low power consumption. all SANYO was, among the input audio signal, the LPF for extracting a bass component, an amplifier for amplifying the LPF output signal, and a rectifier circuit for rectifying the signal level is disposed downstream of said amplifier, rectifying A differential circuit for detecting the rise of the signal level obtained, an integrating circuit for adjusting the pulse width output from the differential circuit to a predetermined time width, and a volume control amplifier for adjusting the level of the LPF output. And a rectifier circuit, a differentiating circuit, and an integrating circuit are connected in series to constitute a low-pitched sound rise detection control circuit. The period of the pulse width of the rising portion of the bass component having passed through the LPF, is added to the input audio signal is obtained so as to achieve bass enhancement.
[0007]
According to the present invention, the psychological effect due to the bass attack is effectively used, the level of only the rising part of the bass is enhanced, and the clear bass is enhanced and reproduced, and it is not necessary to enhance the bass all the time. A bass enhancement circuit that can reduce the load on the power amplifier can be provided.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The bass enhancement circuit of the present invention is characterized by extracting a bass component from an input audio signal, enhancing the bass signal level of only the rising portion of the bass and reproducing the bass signal, and has a good separation. It is possible to achieve bass enhancement with low power consumption.
[0009]
A bass enhancement circuit according to claim 1 of the present invention comprises: an LPF for extracting a bass component from an input audio signal; an amplifier for amplifying the LPF output signal; and a signal disposed downstream of the amplifier. a rectifier circuit for rectifying the level, and differentiating circuit for detecting a rise of the rectified signal level, an integrating circuit for adjusting the pulse width output by the differentiating circuit to a predetermined time width to the level adjusting the LPF output e Bei a volume control amplifier (hereinafter abbreviated as VCA), constitute a bass rising detection control circuit by connecting the integrating circuit and the amplifier and rectifier circuit and the differential circuit in series, resulting in the integration circuit of the rise detection control circuit the resulting period of the pulse width of the rising portion of the bass ones, a bass component having passed through the LPF, and to achieve bass enhancement is added to the input audio signal A.
[0010]
Then, the bass enhancement circuit according to claim 2 of the present invention, an adder for adding the input audio LR signal, and LPF for extracting a bass component is disposed downstream of said adder, the LPF An amplifier for amplifying an output signal, a rectifying circuit for rectifying a signal level, a differentiating circuit for detecting a rise of the rectified signal level, and an integrating circuit for adjusting a pulse width output from the differentiating circuit to a predetermined time width If, a the volume control amplifier the LPF output to the level adjust, constitute a bass rising detection control circuit by connecting the integrating circuit and the amplifier and rectifier circuit and the differential circuit in series, the integral of the rise detection control circuit the period of the pulse width of the rising portion of the bass obtained in the circuit, the bass component having passed through the LPF, is added to the input audio LR signal, bass Strength are those that can be realized with two-channel signal of the audio LR.
[0011]
An embodiment of the present invention will be described below with reference to FIGS.
(Embodiment 1)
An embodiment of the present invention described in claim 1 of the present invention will be described below with reference to FIGS.
[0012]
FIG. 1 is a block diagram showing a bass enhancement circuit according to an embodiment of the present invention. In FIG. 1, 1 is an LPF for extracting bass components, 2 is a bass rise detection control circuit, 3 is an amplifier that amplifies the signal level extracted by the LPF, 4 is a rectifier circuit that rectifies the signal level, 5 is A differentiating circuit for detecting the rise of the rectified signal level, an integrating circuit 6 for adjusting the pulse width output from the differentiating circuit, a VCA 7 for adjusting the signal level of the bass component extracted by the LPF, and 8 This is an adder that adds the input audio signal and the bass part.
[0013]
The operation of the bass enhancement circuit configured as described above will be described. From the input audio signal, only the low frequency component is extracted by the LPF 1, and the signal is amplified by the amplifier 3. The amplified bass component is rectified by the rectifier circuit 4 and its envelope level is output. Next, in order to detect the rising of the envelope, the envelope is differentiated by the differentiating circuit 5 to generate a rising pulse. An integrating circuit 6 is used to appropriately extend the rising pulse width according to the effect. Only when this pulse is at the H level, the bass component extracted by the LPF 1 is passed through the VCA 7 and the adder 8 adds it to the input audio signal using an appropriately time-expanded pulse. Of the bass components, the signal level of only the rising portion is increased. This will be specifically described as follows.
[0014]
Usually, a bass is a typical instrument for reproducing bass, and a case where the bass is played with a bonbon bonbon (called bass running) is considered. In this case, one tone of the bass has a waveform of several cycles, there is a blank, and the next tone comes again several cycles. In other words, it is the intention of the present invention to increase the signal level by several rising cycles of the waveform of several cycles of one bass sound, thereby enhancing the sense of attack.
[0015]
FIG. 2 shows a time-series waveform of each part of the bass enhancement circuit shown in FIG. 1, and is an explanatory diagram when a sine wave is input. That is, when the input audio signal is a low tone only and a waveform (a) is input, the output of the amplifier 3 has a clipped waveform shown in (b). The clipped audio waveform is integrated by the rectifier circuit 4 as shown in FIG. That is, a signal presence / absence section is determined. When this is differentiated by the differentiating circuit 5, a waveform (d) is obtained. (D) The waveform is for detecting a rising portion of a signal from a non-signal and has a narrow pulse width. The time width τ is set to the time width in which the effect is obtained by the integration circuit 6 to obtain the waveform (e). According to an experiment, a time width τ of about several 100 ms is sufficient. Only in the H section of the integration circuit 6, the low frequency component is passed from the VCA and added to the input signal, so that the signal waveform (f) is finally output. As described above, the bass level can be enhanced by increasing the bass signal level only in the rising portion of the bass component.
[0016]
(Embodiment 2)
Next, an embodiment of the invention described in claim 2 of the present invention will be described with reference to FIG. The same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0017]
FIG. 3 is a block diagram showing a bass enhancement circuit according to an embodiment of the present invention. In FIG. 3, 9 is an adder for adding the audio LR signal, 1 is an LPF for extracting a bass component, 2 is a bass onset detection control circuit, 3 is an amplifier for amplifying the signal level extracted by the LPF, 4 Is a rectifying circuit for rectifying the signal level, 5 is a differentiating circuit for detecting the rise of the rectified level, 6 is an integrating circuit for adjusting the pulse width output from the differentiating circuit, and 7 is a bass component extracted by the LPF. VCA 8 for adjusting the signal level of the audio signal and the low frequency component are added to the LR.
[0018]
The operation of the bass enhancement circuit configured as described above will be described. The input signal of the audio LR2 channel is added by the adder 9. Normally, the bass component is an LR in-phase signal at the time of two channels, and thus can be added. From the added signal, the low-frequency component is extracted through the LPF 1 to detect the rising portion of the low frequency component in the same configuration as in the first embodiment, and the low-frequency component is passed through only the rising portion by the VCA 7. By adding each to LR, the circuit can be simplified and the same bass enhancement can be achieved.
[0019]
In the first and second embodiments, the VCA 7 controls the low-frequency component passing control only at the rising portion of the low frequency. However, it can be easily realized by a simple electronic switch and a mute circuit. Needless to say, it is necessary to adjust also.
[0020]
【The invention's effect】
As described above, the bass enhancement circuit of the present invention enhances and reproduces the bass signal level of only the rising portion of the bass, thereby reproducing a crisp, low-pitched bass and, furthermore, a full-time bass enhancement. Therefore, the load on the power amplifier can be reduced, and it is possible to provide a bass enhancement circuit capable of minimizing heat generation.
[0021]
Also, when the response of the speaker is poor, the rising waveform becomes dull and the bass becomes poor, but the dullness of the rising waveform is complemented in advance by the bass enhancement circuit of the present invention, so that it is faithful to the original sound waveform. Bass reproduction by a speaker becomes possible.
[Brief description of the drawings]
FIG. 1 is a block diagram of a bass enhancement circuit according to a first embodiment of the present invention; FIG. 2 is a waveform diagram illustrating the operation of each unit in FIG. 1; FIG. FIG. 4 is a block diagram of a conventional bass enhancement circuit.
1 LPF
2 Bass rise detection control circuit 3 Amplifier 4 Rectifier circuit 5 Differentiator circuit 6 Integrator circuit 7 Volume control amplifier (VCA)
8 Adder 9 Adder

Claims (2)

In the input speech signal, the LPF for extracting a bass component, wherein an amplifier for amplifying the LPF output signal, and a rectifier circuit for rectifying a later stage is arranged on the signal level of the amplifier, the rise of the rectified signal level a differentiating circuit for detecting an integrating circuit for adjusting the pulse width output by the differentiating circuit to the predetermined time width, and the example Bei a volume control amplifier for LPF output level adjusting said amplifier and rectifier circuit differential A low-pitched sound rise detection control circuit is configured by connecting a circuit and an integrating circuit in series, and a low-pitched sound component that has passed through the LPF during a pulse width of a low-pitched rising section obtained by the integrator circuit of the rise detection control circuit. , bass enhancement circuit characterized in that is added to the input audio signal so as to achieve bass enhancement. An adder for adding the input audio LR signal, and LPF for extracting a bass component is disposed downstream of said adder, an amplifier for amplifying the LPF output signal, and a rectifier circuit for rectifying the signal level, the rectification comprising a differentiating circuit for detecting a rising edge of the signal level, an integrating circuit for adjusting the pulse width output by the differentiating circuit to the predetermined time width, and said volume control amplifier for level adjustment of the LPF output, the An amplifier, a rectifier circuit, a differentiating circuit, and an integrating circuit are connected in series to constitute a bass rising detection control circuit, and the LPF is provided during a pulse width of a bass rising portion obtained by the integrating circuit of the rising detection control circuit. bass enhancement circuit the bass component is added to the input audio LR signal, characterized in that so as achieve bass enhancement that has passed through the.

Images