JP2661253B2 - Graphic equalizer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic equalizer, and more particularly to a graphic equalizer used for correcting frequency characteristics of audio equipment and the like.

The equalizer divides the audible frequency band into several frequency bands, and changes the characteristics of each frequency band according to the conditions of the sound field, audibility, etc., thereby changing the frequency characteristics of the entire audible range and changing the sound field. And recording / reproducing according to conditions such as hearing. The graphic equalizer allows the user to change several frequency bands in the audible frequency band by using a variable element, and the correction value can be visually recognized by a display device.

2. Description of the Related Art A conventional graphic equalizer adjusts a variable element such as a volume provided for each frequency band in an audible frequency band while a user looks at a display device or listens to a sound so that the entire audible frequency band can be adjusted. Was corrected.

In addition, there is a type in which predetermined correction is performed using a fixed element, such as a noise and reduction system.

Problems to be Solved by the Invention However, conventional equalizers such as graphic equalizers perform correction while looking at a display device or while listening to sound at a predetermined sound pressure level. As shown in FIG. 4, the frequency characteristics change depending on the sound pressure level. Particularly, at a low sound pressure level, a change such as a large decrease in sensitivity in a low frequency region occurs. There is a problem that the frequency characteristic is different from the previously set frequency characteristic, so that the frequency characteristic has to be set again.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a graphic equalizer that can perform correction according to the sense of hearing of a person by automatically performing correction according to an input signal level. .

Means for Solving the Problems The present invention controls gain independently for each of a plurality of characteristic frequencies by desired setting data, and corrects an input signal according to a desired frequency characteristic set by the setting data. A level detecting means for detecting a level of the input signal; a storage means for storing correction data corresponding to the input signal level detected by the level detecting means; a setting data and the storage means Calculating means for synthesizing the correction data with the correction data, and a frequency characteristic in which a low-frequency component increases as the input signal level decreases to a desired frequency characteristic according to the setting data obtained by the arithmetic means. The input signal is corrected by a synthesized frequency characteristic.

According to the present invention, an input signal is corrected by a synthesized frequency characteristic obtained by synthesizing a frequency characteristic in which a low-frequency component rises as the input signal level decreases to a desired frequency characteristic based on the setting data obtained by the arithmetic means. ,
Correction according to the hearing sensitivity of the human ear is performed according to the input signal level, and the input signal is corrected so as to have a desired frequency characteristic set regardless of the level. The input signal corrected by the frequency characteristics of (1) and (2) can be obtained, and the combined data of the setting data and the correction data combined by the calculation means is used as the setting data of the equalizer. Since it is not necessary to separately perform the correction according to the signal level, and it is not necessary to provide a circuit for each, the circuit configuration can be simplified.

Embodiment FIG. 1 shows a block diagram of an embodiment of the present invention. In the figure, 1 is an operation unit, 2 is a control unit, 3 is an equalizer unit, 4 is a graphic display unit, and 5 is a detection unit.

The operation unit 1 includes up keys 6a to 6g and down keys 7a to 7g. The detection unit 5 includes a filter 8 for removing unnecessary signals from the input signal and an analog / digital (A / D) conversion unit 9 for performing analog-to-digital conversion of the input signal according to its level and generating level data. .

The control unit 2 includes a key input reception unit 10 for generating key data in response to a key operation of the operation unit 1, a level data input reception unit 11 for receiving level data from the detection unit 5 into the control unit 2, and a read only memory (ROM). , An EQ flat preset memory 12 that stores reference value data, an EQ level preset memory 13 that is configured by a read-on memory (ROM) and stores level data corresponding to human hearing characteristics, a random access memory (RAM)
A key data memory 14 for storing key data, an arithmetic unit 15 for generating EQ data from key data, level data, etc., an EQ data output unit for outputting the EQ data of the arithmetic unit 15 to the equalizer unit 3 and the graphic display unit 4 16, arithmetic unit 15
After the arithmetic processing, a time constant control unit 17 for switching the data output time is provided. Time constant control section 17
Is connected to a switch 18, and the time constant is switched by turning on / off the switch 18.

EQ output from the EQ data output unit of the control unit 2
The data is supplied to the equalizer unit 3 and the latch control units 19 and 20 of the graphic display unit 4.

Equalizer 3 latch control unit 19, the shift register 21, f ₁ ~f ₇ latch 22 corresponding to the control resistor 23a~23
g, filters 24a to 24g, and an amplifier circuit 25. The graphic display unit 4 includes a latch control unit 20, a shift register 26, a latch 27, drive circuits 28a to 28g, and display units 29a to 28g.
Consists of 29g.

Latch control units 19 and 20 have E of control unit 2
EQ data and a clock are supplied from the Q data output unit 16, a latch control signal is generated based on these signals, and the latch control signal is supplied to the latch 22.

 Next, the operation of the equalizer will be described with reference to FIG.

First, when the power is turned on (step 30), the presence or absence of a power backup is confirmed when the power is turned off (step 31). If there is no power backup, no data is written in the key data memory 14, so the reference data is read from the EQ flat preset memory 13 and written to the key data memory 14 (step 3).
2).

In the case where a power supply backup is provided, the previous data is stored in the key data memory 14. In this case, the up keys 6a to 6g and the down keys 7a to 7g of the operation unit 1
Can correct the data in the key data memory 14 (steps 33 and 34).

Next, it is checked whether or not level data has been input from the level detector 5 (step 35). If there is no input of level data, steps 33 and 34 are repeated. If there is an input of level data, data corresponding to the level data from the detector 5 is read from the level EQ preset memory 13 (step 36).

The data read from the level EQ preset memory 13 is added to the EQ data in the key data memory 14 by the calculation unit 15 (step 37). Here, it detects whether the time constant set by the switch 18 is fast (FAST) or slow (SLOW).
The data is output to the data output unit 16 (steps 38, 39, 40). Time constant switching switches the time from the detection of the signal level to the output of the EQ data.If this time is shortened, good response characteristics can be obtained, but the change in characteristics becomes sharp. Therefore, a sense of discomfort is noticeable in hearing. In such a case, the data can be heard without discomfort by making the data processing time longer.

The output EQ data is supplied to the equalizer unit 3 and the graphic display unit 4 via the EQ data output unit. In the equalizer unit 3, the supplied EQ data is supplied from the latch control unit 19 to the control resistors 23a to 23g via the shift register 21 and the latch 22. Control resistors 23a to 23g are latched
According to the data from 22, the resistance value changes. When the resistance value of the control resistors 23a to 23g changes, each filter 24a to 24g connected to the inverting terminal of the operational amplifier constituting the amplifier circuit 25
Of the amplifier circuit 25, the amplification degree for each frequency characteristic of the amplifier circuit 25 changes.

In the graphic display unit 4, the EQ data is supplied to the drive circuits 28a to 28g via the shift register 26 and the latch 27, similarly to the equalizer unit 3. Drive circuits 28a to 28g
Drives the displays 29a to 29g according to the input EQ data. The gain of the display 29a to 29g is LE for each frequency.
It is indicated by D (light emitting diode) or the like.

The EQ data is obtained by adding the level-to-EQ preset data, which is correction data according to the input signal level, as shown in FIG. The level EQ preset data, which is the correction data, shows characteristics such that the low frequency region is emphasized when the input signal level is low, and becomes gradually flatter as the input signal level increases.

As described above, according to the present embodiment, if the input signal level changes in the related art, the human hearing sensitivity also changes, and the input and output levels are set in advance by the up and down keys 6a to 6g and 7a to 7g of the operation unit 1. The characteristic that is different from the set frequency characteristic is changed according to the input signal level based on the characteristic according to the iso-equalization curve of the human ear as shown in FIG. Since the frequency characteristics of the equalizer unit 3 are changed by adding the key data and the corrected EQ data, the correction in accordance with the key input of the operation unit 1 can be always performed. In the present embodiment, the level detector 5 detects the level of a predetermined frequency of the input signal. However, the level is detected for each divided frequency band, and data is input for each frequency band. By performing the correction, more accurate correction can be performed.

Further, in the present embodiment, the audible frequency band is divided into seven frequency bands to vary the frequency characteristics. However, the frequency characteristic is not limited to seven, and may be smaller or larger.

Effect of the Invention As described above, according to the present invention, a desired frequency characteristic based on the setting data obtained by the calculating means is combined with a frequency characteristic in which a low-frequency component rises as the input signal level decreases, by a composite frequency characteristic obtained by combining the frequency characteristics. By correcting the input signal, correction is performed according to the hearing sensitivity of the human ear according to the input signal level, and the input signal is corrected so as to have a desired frequency characteristic set regardless of the level. An input signal corrected with a desired frequency characteristic can be obtained irrespective of the level of the input signal, and the combined data of the setting data and the correction data combined by the calculation means is used as the setting data of the equalizer. It is not necessary to separately perform a specific setting and a correction according to the input signal level, and there is no need to provide a circuit for each. It has features such as being able to simply.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation of one embodiment of the present invention, FIG. The figure is a characteristic diagram of the hearing sensitivity of the human ear. DESCRIPTION OF SYMBOLS 1 ... Operation part, 2 ... Control part, 3 ... Equalizer part, 4 ... Graphic display part, 5 ... Level detection part, 12 ... EQ flat preset memory, 13 ... Level / EQ preset memory, 14 …… Key data memory, 15…
... Calculation unit.

Claims (1)

(57) [Claims] 1. A graphic equalizer for controlling gain independently for each of a plurality of specific frequencies by desired setting data and correcting an input signal in accordance with a desired frequency characteristic set by the setting data. Level detection means for detecting the level of the input signal; storage means for storing correction data corresponding to the input signal level detected by the level detection means; and setting data and correction data for the storage means. Calculating means for synthesizing by a calculation, a synthesized frequency characteristic obtained by synthesizing a frequency characteristic in which a low-frequency component increases as the input signal level decreases to a desired frequency characteristic based on the setting data obtained by the arithmetic means. A graphic equalizer for correcting the input signal in response to the input signal.