JPH05145992A - Low frequency range characteristic correcting circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to a low-frequency range correction circuit suitable for application to an audio amplification circuit in a television receiver, and corrects human auditory characteristics at a low volume, and also has a maximum output power. It also provides a correction circuit that suppresses an excessive volume that exceeds the dynamic range of the audio signal amplification circuit, which is limited. [Composition] By passing the low-range signal only through the voltage-controlled amplifier circuit 6, the low-range signal increases the low-range amplification factor, and when the low-range signal is large, the low-range amplification factor increases. Therefore, it also functions as a correction circuit that corrects the human auditory characteristics at low volume and suppresses excessive volume.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as a technique in this field, a volume controller is used as shown in FIGS. 4 and 5 in order to correct the characteristic that human hearing makes it difficult to hear sounds in the low range when the volume is low. By controlling the correction of the low frequency range characteristic in conjunction with it, if the overall attenuation of the volume control is set to a large value, the low frequency range attenuation is made relatively small, and as a result, it seems that the low frequency range is enhanced. Conversely, if the overall attenuation of the volume control is set to a small value, the attenuation in the low range becomes equal to the overall attenuation, and the amplification rate in the low range decreases. Had occupied.

[0003]

However, in the circuit having the above-mentioned structure, the average level of the input signals is different even if the audio signals have the same contents because the enhancement ratio in the low frequency range is linked to the volume controller. However, when listening at a similar volume, the degree of the effect is different, and there is a problem that it is not possible to effectively correct the low range in the sense of hearing when the volume is low.

[0004]

In order to solve the above problems, the present invention uses an effective value conversion circuit and a voltage control type amplification circuit to amplify a low frequency range according to the level of an input signal. The ratio is controlled to effectively correct the low sound range in the sense of hearing when the volume is low.

[0005]

According to the present invention, as described above, since the amplification ratio of the low frequency range is controlled according to the level of the input signal or the level of the low frequency range component, if the audio signals of the same content are input, Even if the average level of the signal is different, the effect is the same when listening at the same volume, and it is possible to effectively perform the correction of the low frequency range in the sense of hearing when the volume is low.

[0006]

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

FIG. 1 is a schematic configuration block diagram of a bass range characteristic correction circuit showing a first embodiment of the present invention, and FIG. 2 is a schematic configuration block diagram of a bass range characteristic correction circuit showing a second embodiment of the present invention. Is.

In FIG. 1, 1 is an input terminal, 2 is an output terminal, 3 is a high frequency band pass filter, 4 is a low frequency band pass filter, 5 is an effective value circuit, 6 is a voltage control type amplifier circuit, 7
Is an adder circuit.

In the circuit of FIG. 1, the signal input to the input terminal 1 is input to the high frequency band pass filter 3 and the low frequency band pass filter 4, and the output signal of the low frequency band pass filter 4 is an effective value conversion circuit 5. The effective value is detected, and the detected output is used to control the low frequency component signal of the input signal, which is the output of the low frequency band pass filter 4, by the voltage control type amplifier circuit 6, and the output signal and the high frequency band pass filter. The treble range component, which is the output of -3, is added by the adding circuit 7 and output from the output terminal 2.

In FIG. 2, reference numeral 8 is an adder circuit. Figure 2
In the circuit, the signal of each channel input to the input terminal 1 is input to the treble band pass filter 3 and the addition circuit 8, and the output signal of the addition circuit 8 is input to the bass band pass filter-4, The effective value of the output of the pass filter-4 is detected by the effective value conversion circuit 5, and the detected output is used to amplify the signal of the low frequency component of the input signal, which is the output of the low frequency band pass filter-4, by voltage control type amplification. Controlled by the circuit 6, the output signal and the treble range component that is the output of the treble range pass filter-3 of each channel are added by the adder circuit 7 and output from the output terminal 2.

Note that the present invention is not limited to the above-described embodiment, and based on the gist of the present invention, for example, a voltage control type amplifier circuit may be a current control type, or all circuits may be processed by digital signal processing. Various modifications are possible, such as
They are not excluded from the scope of the present invention.

[0012]

As described above in detail, according to the present invention, the amplification factor increases as the level of the input signal decreases, and the amplification factor decreases as the level of the input signal increases. Since the audio signal is inserted in the low-pitched sound path, there are two effects, that is, low-pitched sound correction in the auditory sense when the audio signal is at a low level and suppression of distortion when the audio signal is at an excessive level. It can also be constructed at low cost.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a bass range characteristic correction circuit showing a first embodiment of the present invention.

FIG. 2 is a schematic block diagram of a bass range characteristic correction circuit showing a second embodiment of the present invention.

FIG. 3 is a control characteristic diagram of the voltage control type amplifier circuit according to the embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a conventional circuit.

5 is a schematic diagram of operating characteristics of the circuit of FIG.

[Explanation of symbols]

 1 Input Terminal 2 Output Terminal 3 High Band Pass Filter-4 Low Band Pass Filter-5 Effective Value Circuit 6 Voltage Controlled Amplifier Circuit 7 Adder Circuit 8 Adder Circuit

Claims (2)

[Claims] 1. A 1-channel input / output terminal, a high-pass filter and a low-pass filter, each of which receives a signal input from the input terminal, and an output which receives the output of the low-pass filter. A value control circuit, a voltage control type amplifier circuit which receives the output of the bass pass filter and whose signal amplification factor is controlled by the output of the effective value circuit, an output of the voltage control type amplifier circuit and the treble range It is equipped with an adder circuit that synthesizes the output of the pass filter, and by adding the low range signal extracted according to the effective value of the entire band of the input audio signal to the source signal, it is possible to reduce the audibility at a low volume. Low-range characteristic correction circuit characterized by suppressing the low-range distortion at the time of range correction and excessive volume. 2. A 2-channel input / output terminal, a 2-channel high-pass filter which receives signals input from the respective input terminals, an adder circuit which adds the 2-channel input signals, and the adder. A low-pass filter having an output of the circuit as an input, an effective value circuit having the output of the low-pass filter as an input, and an output of the low-pass filter as an input, and a signal by the output of the effective value circuit. Of an input audio signal, which includes a voltage control type amplifier circuit whose amplification factor is controlled, and an adder circuit for two channels which synthesizes the output of the voltage control type amplifier circuit and the output of each of the treble band pass filters. Depending on the effective value of the entire band of
A bass range characteristic correction circuit, which is characterized by adding the extracted bass range signal to the source signal to suppress the bass range in the sense of hearing at a low volume and suppress the distortion of the bass range at an excessive volume.