CN101489165A - Audio frequency compensation apparatus - Google Patents

Abstract

An audio compensation device, comprising a left input terminal and a right input terminal for respectively receiving the left and right channel sound input signals output by a player, and a left output terminal and a right output terminal for respectively outputting the left and right channel sound input signals. 1. The sound input signal of the right channel is sent to an earphone. The audio compensation device further includes a frequency compensation unit. The frequency compensation unit is coupled between the left and right input terminals and the left and right output terminals, and is used to select the low-range components of the left and right channel sound input signals input from the left and right input terminals, After amplifying and adjusting the amplitude, it is cross-coupled to the sound input signals of the left and right channels. The above-mentioned audio compensation device can improve the bass effect of the sound output by the earphone, and can be realized with a simple analog circuit.

Description

audio compensation device

technical field

The invention relates to an audio compensation device, in particular to an audio compensation device with low audio compensation.

Background technique

With the development of audio technology, audio players are used more and more in daily life. However, when the earphones with poor bass range response are used for playback, the low range components of the output sound of the audio player cannot be fully played on the earphones, resulting in poor bass effect of the player output sound.

The publication date is November 6, 1996, and the Chinese patent with the publication number CN1135120 discloses a bass enhancement circuit. The circuit uses a low-pass filter to extract the low-range components below the low-range reproduction range of the earphone in the sound input signal, and generates the even-order harmonics of the above-mentioned low-range components through full-wave rectification, and extracts the second harmonic of the even-order harmonics , amplify it to an appropriate level and add it to the sound input signal. However, the low-frequency components of the left and right channel sound input signals selected by the low-pass filter circuit of the bass enhancement circuit cannot be adjusted, resulting in an unsatisfactory bass effect of the earphone output sound.

Based on the above problems, the present invention provides an audio compensation device, which can adjust the low-range components of the selected output sound, and improve the bass effect of the earphone output sound.

Contents of the invention

An audio compensation device, comprising a left input terminal and a right input terminal for respectively receiving a left channel sound input signal and a right channel sound input signal output by a player, a left output terminal and a right output terminal For respectively outputting the sound input signals of the left and right channels, a frequency compensation unit, the frequency compensation unit includes a first and second order low-pass filter circuit, a first DC blocking capacitor, a third potentiometer, a A second second-order low-pass filter circuit, a second DC blocking capacitor and a fourth potentiometer. In the first second-order low-pass filter circuit, the first DC-blocking capacitor and the third potentiometer are sequentially connected in series between the right input terminal and the left output terminal; the second second-order low-pass filter circuit, The second DC blocking capacitor and the fourth potentiometer are sequentially connected in series between the left input terminal and the right output terminal. The first second-order low-pass filter circuit includes a first potentiometer and a first operational amplifier. The first potentiometer has an adjustment terminal connected to the non-inverting input terminal of the first amplifier, and the adjustment terminal is adjusted to change The first second-order low-pass filter circuit selects the low-range component of the right-channel sound input signal, amplifies it, adjusts its amplitude, and then cross-couples it to the left-channel sound input signal. The second second-order low-pass filter circuit includes a second potentiometer and a second operational amplifier. The second potentiometer has an adjustment terminal connected to the non-inverting input terminal of the second amplifier, and the adjustment terminal is adjusted to change The low-range components of the left-channel sound input signal selected by the second second-order low-pass filter circuit are amplified, adjusted in amplitude, and then cross-coupled to the right-channel sound input signal.

The advantage of the present invention is that the above-mentioned audio compensation device can adjust the selected low-frequency components, thereby improving the low-frequency effect of the earphone output sound.

Description of drawings

FIG. 1 is a schematic diagram of an audio compensation device of the present invention located in a player.

FIG. 2 is a circuit diagram of an embodiment of the audio compensation device of the present invention.

FIG. 3 is a schematic diagram of the audio compensation device of the present invention as an independent module connected between the player and the earphone.

FIG. 4 is a schematic diagram of the audio compensation device of the present invention located inside the earphone.

Detailed ways

See Figure 1. The audio compensation device 1 of the present invention is placed inside the player 2 . The player further includes an audio output interface 21 for connecting an earphone 3 . The audio signal output by the player 2 is subjected to audio compensation by the audio compensation device 1 , and then input to the earphone 3 through the audio output interface 21 for playback.

Please refer to FIG. 2 . FIG. 2 is a circuit diagram of an embodiment of the audio compensation device of the present invention. Described audio compensation device 1 comprises a right input end 11, is used for receiving a right channel sound input signal S1; A left input end 12, is used for receiving a left channel sound input signal S2; A right output end 13, uses outputting the right channel audio input signal S1; and a left output terminal 14 for outputting the left channel audio input signal S2. The audio compensation device 1 further includes a frequency compensation unit 10 . The frequency compensation unit 10 is coupled between the input terminals 11, 12 and output terminals 13, 14, and is used to select the right channel sound input signal S1 received by the right input terminal 11 and the input signal S1 received by the left input terminal 12. The low-range components of the left-channel sound input signal S2 of the left-channel sound input signal S2 are respectively cross-coupled to the right-channel sound input signal S1 output by the right output terminal 13 and the left The left channel sound input signal S2 outputted from the output terminal 14.

The frequency compensation unit 10 includes a first second-order low-pass filter circuit 15, a first DC blocking capacitor C3, a third potentiometer SW3; a second second-order low-pass filter circuit 16, a second DC blocking Capacitor C6, a fourth potentiometer SW4. The input end of the first second-order low-pass filter circuit 15 is electrically connected to the right input end 11 , and its output end is electrically connected to one end of the first DC blocking capacitor C3 . The other end of the DC blocking capacitor C3 is electrically connected to the input end of the third potentiometer SW3, the output end of the third potentiometer SW3 is grounded, and its adjustment end 17 is electrically connected to the left side of the audio compensation device 1. Output 14. The sound input signal S1 of the right channel is selected and amplified by the first second-order low-pass filter circuit 15, and the DC signal is suppressed by the first DC blocking capacitor C3, and then passed by the third potential After amplitude adjustment by the switch SW3, a right low-range sound signal S1' is obtained. The adjusting end 17 of the third potentiometer SW3 couples the right low-range sound signal S1' to the left channel sound input signal S2 output by the left output end 14, and obtains a coupled sound signal S2 + S1 ′, output the coupled sound signal S2+S1 ′ as the output sound signal of the left output terminal 14 . In different implementations, the adjustment end 17 of the third potentiometer SW3 can be adjusted through an adjustment knob (not shown) externally provided on the player 2, thereby changing the level of the right low-range sound signal S1'. The magnitude of the amplitude makes it consistent with the amplitude wave of the left channel sound input signal S2.

Similarly, the input end of the second second-order low-pass filter circuit 16 is electrically connected to the right input end 12 , and its output end is electrically connected to one end of the second DC blocking capacitor C6 . The other end of the DC blocking capacitor C6 is electrically connected to the input end of the fourth potentiometer SW4, the output end of the fourth potentiometer SW4 is grounded, and its adjustment end 18 is electrically connected to the right side of the audio compensation device 1. Output 13. The left channel sound input signal S2 is selected and amplified by the second second-order low-pass filter circuit 16, and the DC signal is suppressed by the second DC blocking capacitor C6, and then passed by the fourth potential Switch SW4 performs amplitude adjustment processing and obtains a left low-range sound signal S2'. The adjustment end 18 of the fourth potentiometer SW4 couples the left low range sound signal S2' to the right channel sound input signal S1 output by the right output end 13, and obtains a coupled sound signal S1 + S2 ′, outputting the coupled sound signal S1+S2 ′ as the output sound signal of the right output terminal 13 . Similarly, the adjusting end 18 of the fourth potentiometer SW4 can also be adjusted by an external adjusting knob (not shown) on the player 2, thereby changing the amplitude of the left low-range sound signal S2' , so that it is consistent with the amplitude of the right channel sound input signal output by the right output terminal 13 .

The first second-order low-pass filter circuit 15 further includes resistors R1, R2 and R3, a first potentiometer SW1, capacitors C1 and C2, and a first operational amplifier U1. The resistor R1 and the first potentiometer SW1 are connected in series between the right input terminal 11 and the non-inverting input terminal of the first operational amplifier U1; wherein, the adjustment terminal of the first potentiometer SW1 is electrically connected to The non-inverting input terminal of the first operational amplifier U1. The resistor R2 is connected between the inverting terminal of the first operational amplifier U1 and the ground, the resistor R3 is connected between the input terminal and the inverting terminal of the first operational amplifier U1, and is connected with the resistor R2 realizes the negative feedback of the operational amplifier U1. The capacitors C1 and C2, the resistor R1 and the first potentiometer SW1 form a secondary RC filter link, wherein the capacitor C1 is electrically connected to the output terminal of the operational amplifier U1, and is used to introduce an appropriate amount of positive feedback to improve the amplitude-frequency Characteristics: the capacitor C2 is electrically connected between the non-inverting input terminal of the first operational amplifier U1 and ground. The adjustment end of the first potentiometer SW1 can be adjusted through an adjustment knob (not shown) externally provided on the player 2, so as to change the frequency of the right low-range sound signal output by the secondary RC filter link. characteristic.

The second second-order low-pass filter circuit 16 further includes resistors R4, R5 and R6, a second potentiometer SW2, capacitors C4 and C5, and a second operational amplifier U2. The resistor R4 and the second potentiometer SW2 are connected in series between the left input terminal 12 and the non-inverting input terminal of the second operational amplifier U2; wherein, the adjustment terminal of the second potentiometer SW2 is electrically connected to The non-inverting input terminal of the second operational amplifier U2. The resistor R5 is connected between the inverting terminal of the second operational amplifier U2 and the ground, the resistor R6 is connected between the input terminal and the inverting terminal of the second operational amplifier U2, and is connected with the resistor R5 realizes the negative feedback of the operational amplifier U1. The capacitors C4 and C5, the resistor R4 and the second potentiometer SW2 form a secondary RC filter link, wherein the capacitor C4 is electrically connected to the output terminal of the operational amplifier U2, and is used to introduce an appropriate amount of positive feedback to improve the amplitude-frequency Characteristics: the capacitor C5 is electrically connected between the non-inverting input terminal of the first operational amplifier U1 and ground. The adjustment end of the second potentiometer SW2 can be adjusted through an adjustment knob (not shown) on the player 2 to change the frequency of the left low-range sound signal output by the secondary RC filter link. characteristic.

The right channel sound input signal S1 is input to the first second-order low-pass filter circuit 15, and the low-range components are selected through the second-stage RC filtering link and amplified by the first operational amplifier U1, and then the first operational amplifier U1 The DC blocking capacitor C3 filters out the DC component, and the amplitude is adjusted by the third potentiometer SW3 to obtain a right low range sound signal S1', and the right low range sound signal S1' is coupled to the left output terminal 14. The left channel sound input signal S2, so the left output terminal 14 outputs a coupled sound signal S2+S1'.

Similarly, after the left channel sound input signal S2 is processed by the second low-pass filter circuit 16, the second DC blocking capacitor C6 and the fourth potentiometer SW4, a left low-range sound signal S2' is obtained. The sound domain sound signal S2' is coupled with the sound input signal S1 of the right channel at the right output end 13, so the right output end 13 outputs a coupled sound signal S1+S2'.

See Figures 3 and 4. FIG. 3 is a schematic diagram of the audio compensation device of the present invention as an independent module connected between the player and the earphone. The audio compensation device 1 is an independent module connected between the player 2' and the earphone 3. The player 2' is connected to the frequency compensation device 1 through an audio output interface 21, and the audio compensation device 1 is connected to an earphone 3. The left and right channel sound input signals output by the player 2' are input to the audio compensation device 1 through the audio output interface 21 for audio compensation, and output a coupled sound signal. The earphone 3 plays the coupled sound signal. FIG. 4 is a schematic diagram of the audio compensation device of the present invention located inside the earphone. The audio compensation device 1 of the present invention is placed inside an earphone 3'. The earphone 3 also includes an earphone body 31 . The player 2' outputs a left channel sound signal and a right channel sound signal through the audio interface 21, the earphone 3' receives the left and right channel sound signals, and the audio compensation device 1 processes The left and right channel sound signals output a cross-coupling sound signal, and the earphone body 31 outputs the cross-coupling sound signal. In FIG. 3 and FIG. 4 , the audio compensation method of the audio compensation device 1 is the same as that in FIG. 1 , so it will not be repeated here.

To sum up, the coupled sound signals S1+S2' and S2+S1' are respectively obtained through the right output terminal 13 and the left output terminal 14.

Therefore, by adopting the above method, the audio compensation device can perform bass compensation on the sound signal output by the player, so as to strengthen the bass part of the sound signal output by the player, enhance the bass effect, and obtain a stereo output.

Claims (4)

1. [claim 1] a kind of audio frequency compensation apparatus, comprise that a left input and a right input are used for receiving respectively a L channel audio input signal and a right channel sound input signal, an one left output and a right output are used for exporting respectively a described left side, the right channel sound input signal, one frequency compensation unit, described frequency compensation unit comprises one first second-order low-pass filter circuit, one first capacitance, one second second-order low-pass filter circuit and one second capacitance, the described first second-order low-pass filter circuit and first capacitance are connected in series between described right input and the described left output; The described second second-order low-pass filter circuit and second capacitance are connected in series between described left input and the described right output, it is characterized in that, the described first second-order low-pass filter circuit comprises one first potentiometer, one first operational amplifier, described first potentiometer has one and adjusts the in-phase input end that end is connected in described first operational amplifier, regulates right the hang down range voice signal of this adjustments end with the described right channel sound input signal that changes the described first second-order low-pass filter circuit and choose; The described second second-order low-pass filter circuit comprises one second potentiometer, one second operational amplifier, described second potentiometer has one and adjusts the in-phase input end that end is connected in described second operational amplifier, regulates this adjustments end and hangs down the range voice signal with a left side of the described L channel audio input signal that changes the described second second-order low-pass filter circuit and choose.
2. [claim 2] audio frequency compensation apparatus as claimed in claim 1, it is characterized in that, described frequency compensation unit also comprises one the 3rd potentiometer and one the 4th potentiometer, described the 3rd potentiometer comprises that one adjusts end and is electrically connected on described left output, is used to adjust the amplitude of the low range voice signal in the described right side of described first second-order low-pass filter circuit output; Described the 4th potentiometer comprises that one adjusts end and is electrically connected on described right output, is used to adjust the amplitude of the low range voice signal in a described left side of described second second-order low-pass filter circuit output.
3. [claim 3] audio frequency compensation apparatus as claimed in claim 1 is characterized in that described audio frequency compensation apparatus places in the described player.
4. [claim 4] audio frequency compensation apparatus as claimed in claim 3 is characterized in that described audio frequency compensation apparatus places in the described earphone.

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