JPH0585116U - Graphic equalizer circuit - Google Patents

Abstract

(57) [Abstract] [Object] An object of the present invention is to provide a graphic equalizer circuit which has a small error with respect to the amplitude gain setting value of each preset frequency and can obtain a smooth total frequency characteristic. . [Constitution] In a graphic equalizer circuit that divides a frequency band into a plurality of frequencies and sets the amplitude gain of a preset frequency in each divided frequency band to set the total frequency characteristic, the frequency band division is equally spaced. Configure to do.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a graphic equalizer circuit.

[0002]

[Prior Art]

 A conventional graphic equalizer circuit divides a frequency band into a plurality of bands and sets the amplitude gain of a preset frequency in each of the divided frequency bands to set the total frequency characteristic as shown in FIG. The preset frequency f1 to f7, which is the center frequency in each frequency band, is set not at equal intervals, for example, f1 = 60Hz, and then 120Hz, 250Hz, 500Hz, 1kHz, 3.5kHz, 10kHz in order. Also, since the filter characteristic F of each frequency band is broad, the total frequency characteristic becomes like the curve C for the amplitude gain setting value L of each preset frequency, and for the amplitude gain setting value L, As a result, the error becomes several dB, and further, it was not possible to obtain a natural smooth characteristic in the connection between the frequency bands.

[0003]

[Problems to be solved by the device]

 An object of the present invention is to provide a graphic equalizer circuit which has a small error with respect to the amplitude gain setting value of each preset frequency and can obtain a smooth total frequency characteristic.

[0004]

[Means for Solving the Problems]

 The graphic equalizer circuit of the present invention divides the frequency band into a plurality of frequencies, and sets the amplitude gain of the preset frequency in each divided frequency band to set the total frequency characteristic. It is configured so that the division is performed at regular intervals.

[0005]

[Action]

 When setting the overall frequency characteristics by dividing the frequency band into multiple and setting the amplitude gain of the preset frequency in each divided frequency band, divide the frequency band into equal intervals, and Since the determined frequency characteristic is set for each frequency band, a smooth equalizer characteristic with no error can be obtained with respect to the amplitude gain setting value of each preset frequency.

[0006]

【Example】

 FIG. 1 is a specific configuration diagram of an embodiment of a graphic equalizer circuit according to the present invention, and FIG. 2 is a frequency characteristic diagram of the circuit of FIG. In FIG. 1, 1 is an input terminal, 2a to 2g are bandpass filters having a frequency characteristic such as F in FIG. 2, and 3a to 3g are gain control amplifiers and gain setting values of each band. (L in FIG. 2) is set, 4 is an adder for adding the output of each band, and 5 is an output terminal. In FIG. 2, the vertical axis represents the gain (dB), and the horizontal axis represents the logarithmic frequency. The frequency settings of preset frequencies f1 to f7, which are the center frequencies in each frequency band, are set at equal intervals, for example, f1 = 60Hz, and in the following order 141Hz, 330Hz, 775Hz, 1.82kHz, 4.26kHz, 10kHz. .. According to the sampling theorem, if sample values are given at equal intervals, and if the interval is τ, then a smooth curve connecting the sample values can be obtained as a waveform with a frequency component of 1/2 τ or less. Therefore, C is obtained as the total frequency characteristic of the total sum of each band, and a smooth equalizer characteristic with no error with respect to the gain setting value L which is a sample value is obtained. At this time, the bandpass filter characteristic F (f) of each band is given by the following formula 1.

[0007]

[Equation 1]

In this way, the characteristics of the bandpass filter obtained from the sampling theorem are reproduced by the bandpass filters 2a to 2g of FIG. 1, and the amplitude gain setting values of FIG. The total frequency characteristic C of FIG. Although the filter characteristics of the gain control amplifiers 3a to 3g shown in FIG. 1 are assumed to be ideal filter characteristics based on the sampling theorem in the above embodiment, they may be characteristics using a fluency function.

[0009]

[Effect of the device]

 According to the graphic equalizer circuit of the present invention, it is possible to obtain an equalizer having a smooth total frequency characteristic with no error with respect to the amplitude / gain setting value of each preset frequency.

[Brief description of drawings]

FIG. 1 is a detailed configuration diagram of an embodiment of a graphic equalizer circuit according to the present invention.

FIG. 2 is a frequency characteristic diagram of the circuit of FIG.

FIG. 3 is a frequency characteristic diagram of a conventional graphic equalizer circuit.

[Explanation of symbols]

 1 Input terminal 2a to 2g Band pass filter 3a to 3g Gain control amplifier 4 Adder 5 Output terminal F Filter characteristic L Amplitude gain setting value C Overall frequency characteristic f1 to f7 Preset frequency

Claims (1)

[Scope of utility model registration request] 1. A graphic equalizer circuit that sets a total frequency characteristic by dividing a frequency band into a plurality of frequencies and setting amplitude gains of preset frequencies in the respective divided frequency bands. A graphic equalizer circuit, characterized in that the frequency characteristic is determined for each frequency band by setting the frequency characteristic determined by the division interval.