JPH05145993A - Low frequency range reinforcing circuit - Google Patents

Abstract

PURPOSE:To suitably correct a low frequency range corresponding to low and high volume by controlling the reinforcing effect of the low frequency with the valid value of an input signal. CONSTITUTION:The RMS value of the input signal to an input terminal 1 is detected by an RMS valuing circuit 3 and according to the detected output, a voltage controlled amplifier circuit 5 to input the output of a low-pass filter 4 is controlled. The output signal and a source signal are added by an adder circuit 6 and outputted later. Thus, since the reinforcing amount of the low frequency is adjusted corresponding to the RMS value of the input signal or a low frequency signal, the low frequency can effectively be reinforced, the reinforcing effect is suppressed in the case of excess volume, and distortion can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bass booster circuit in a voice amplifier circuit.

[0002]

2. Description of the Related Art Conventionally, as a technique in this field, a technique having a fixed low-frequency range enhancement rate as shown in FIG.

[0003]

However, in the circuit having the above configuration, since the enhancement rate in the low frequency range is fixed, the signal is distorted immediately when the volume is excessively high. Therefore, it is necessary to set the enhancement rate conservatively. Therefore, there has been a problem that the bass range cannot be effectively enhanced at a low volume.

[0004]

In order to solve the above problems, the present invention detects the effective value of an input signal and controls the enhancement rate of the low frequency range in accordance with the effective value to reduce the audibility at a low volume. The present invention is intended to effectively correct and enhance the sound range, and reduce the sense of distortion at high volume.

[0005]

According to the present invention, the bass amplification factor is controlled according to the level of the input signal or the bass component level as described above, so that the bass can be sufficiently enhanced even at a low volume. However, at the same time, it works to suppress the signal enhancement so as not to exceed the dynamic range even at high volume, and reduces the feeling of distortion compared to when the enhancement rate is fixed.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a bass range enhancing circuit showing a first embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a bass range enhancing circuit showing a second embodiment of the present invention, and FIG. Third of the present invention
FIG. 4 is a schematic configuration diagram of a bass range enhancing circuit showing an embodiment of FIG. 4, and FIG. 4 is a schematic configuration diagram of a bass range enhancing circuit showing a fourth embodiment of the present invention.

In FIGS. 1 and 2, 1 is an input terminal, 2 is an output terminal, 3 is an effective value circuit, 4 is a low-pass filter, 5 is a voltage control type amplifier circuit, 6 is an addition circuit, and FIG. 4, reference numeral 7 is an adder circuit.

In FIG. 1, the signal input to the input terminal 1 has its effective value detected by the effective value conversion circuit 3, and its detected output is the voltage control type with the output of the low-pass filter 4 as an input. The amplifier circuit 5 is controlled, and its output signal
The source signal is added by the adder circuit 6 and output from the output terminal 2.

In FIG. 2, the signal input to the input terminal 1 is input to the low-pass filter 4, the effective value of the output of the low-pass filter 4 is detected by the effective value conversion circuit 3, and the detection is performed. The output controls the voltage control type amplifier circuit 5 to which the output of the low pass filter 4 is input, and the output signal and the source signal are added by the adder circuit 6 and output from the output terminal 2.

In FIG. 3, the audio signals input to the respective channels are added by the adder circuit 9, and the output signal is
The rms value conversion circuit 3 detects the rms value, and the detected output controls the voltage control type amplifier circuit 5 which receives the output of the low-pass filter 4 as an input, and outputs the output signal and the source signal of each channel. And are respectively added by the adder circuit 6 and output from the output terminal 2.

In FIG. 4, the audio signals input to the respective channels are added by the adder circuit 9, and the output signal is
The rms value conversion circuit 3 detects the rms value, and the detected output controls the voltage control type amplifier circuit 5 which receives the output of the low-pass filter 4 as an input, and outputs the output signal and the source signal of each channel. And are respectively added by the adder circuit 6 and output from the output terminal 2.

Further, in FIGS. 3 and 4, when the circuits configured in FIGS. 1 and 2 are required for two channels for stereo and the localization of the low range does not pose a problem, the effective value conversion circuit 3 and the low range are arranged. Only one circuit consisting of the pass filter 4 and the voltage control type amplifier circuit 5 is sufficient, and the rate of adding the bass signal according to the level of the input audio signal described in the first embodiment is adjusted to be small. A bass range enhancing circuit that enhances the bass tone at volume and suppresses the bass range distortion at a loud volume, and adds the bass range signal according to the bass range signal level of the input audio signal described in the second embodiment. It is possible to inexpensively configure a bass range enhancing circuit for a stereo system, which adjusts the ratio to enhance the bass feeling at a low volume and suppresses the bass range distortion at a loud volume.

The present invention is not limited to the above-mentioned embodiment, and based on the gist of the present invention, for example, a current control type amplifier circuit is used instead of the voltage control type amplifier circuit, or an effective value conversion circuit. Various modifications are possible such as using an averaging circuit instead of, and these are not excluded from the scope of the present invention.

[0015]

As described above in detail, according to the present invention, since the voltage control type amplifier circuit is controlled in accordance with the effective value of the input signal or the bass signal, the bass boosting amount is adjusted.
It is possible to effectively enhance the bass range regardless of the volume, and to suppress the enhancement effect at the time of excessive volume and reduce the feeling of distortion.

If the circuit configuration according to claims 3 and 4 is adopted, it can be realized at low cost.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a bass enhancement circuit showing a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a bass enhancement circuit showing a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a bass boost circuit showing a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a bass boost circuit showing a fourth embodiment of the present invention.

FIG. 5: Input / output characteristics of voltage-controlled amplifier circuit

FIG. 6 is a schematic configuration diagram of a conventional circuit.

[Explanation of symbols]

 1 Input Terminal 2 Output Terminal 3 Effective Value Circuit 4 Bass Pass Filter 5 Voltage Controlled Amplifier Circuit 6 Adder Circuit 7 Adder Circuit 11 Input Terminal 12 Output Terminal 13 Bass Pass Filter 14 Adder Circuit

Claims (4)

[Claims] 1. A 1-channel input / output terminal, a low-pass filter and an effective value conversion circuit for inputting a signal input from the input terminal, and an output for the low-pass filter as an input. A voltage control type amplification circuit in which the amplification factor of the signal is controlled by the output of the binarization circuit, and an addition circuit for synthesizing the output of the voltage control amplification circuit and the source signal are provided. By adding the low range signal extracted according to the effective value to the source signal, the low range enhancement circuit that enhances the low range at low volume and suppresses the low range distortion at excessive volume. 2. A 1-channel input / output terminal, a low-pass filter that receives a signal input from the input terminal, an effective value conversion circuit that receives an output of the low-pass filter, and the low-pass filter. A voltage control type amplifier circuit whose input is the output of the range pass filter and whose amplification factor is controlled by the output of the RMS circuit, and an adder circuit which combines the output of the voltage control type amplifier circuit and the source signal. By adding the low range signal extracted according to the effective value of the low range signal of the input audio signal to the source signal, it is possible to enhance the low range at low volume and suppress low range distortion at excessive volume. Range enhancement circuit. 3. A two-channel input / output terminal, a summing circuit for two-channel input signals input from this input terminal, and a low-pass filter and an effective value converting circuit having the output of the summing circuit as each input. And a voltage control type amplifier circuit whose input is the output of the low pass filter and whose amplification factor is controlled by the output of the RMS circuit, the output of the voltage control type amplifier circuit and the source signal of each channel. And an adder circuit that synthesizes the bass signal to adjust the ratio of the bass signal added according to the level of the input audio signal, to enhance the bass feeling at low volumes and to suppress the bass distortion at high volumes. circuit. 4. A 2-channel input / output terminal, an adder circuit for 2-channel input signals input from the input terminal, a low-pass filter having the output of the adder as an input, and the low-pass filter. A voltage control type amplifier circuit having the output of the input as an input, a voltage control type amplifier circuit having the output of the bass pass filter as an input, and the amplification factor of the signal being controlled by the output of the effective value converting circuit, and the voltage control type amplification circuit. An addition circuit for synthesizing the output of the circuit and the source signal of each channel is provided, and the bass addition feeling at a low volume is enhanced by adjusting the ratio of addition of the bass range signal according to the bass range signal level of the input audio signal. Bass boost circuit that suppresses distortion in the bass range at high volume.