JPS6238339Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an equalizer circuit device.
The purpose is to improve the characteristics.

For example, as this type of equalizer circuit device,
As shown in Fig. 1, a differential amplifier 1, a resonator 2 (21,
22~2n), gain adjustment resistor 3 (31, 32, ~
3n), when the resistors 4 and 5 are formed, that is, when the input impedance characteristics of the resonator 2 are directly synthesized by the amplifier 1, the characteristics at the maximum and minimum values obtained by the gain adjustment resistor 3 are obtained. It will be done. However, the characteristics from the middle to the minimum change position are poor, and a graphic equalizer with multiple frequency points tends to become a level controller for the entire band. The reason for this is that the combined value of the gain adjustment resistor 3 limits the maximum gain increase/decrease given by the input impedance of the resonator 2 with respect to the resistors 4 and 5. The resistance value of the adjustment resistor 3 must be increased. Therefore, the resistor 3 is placed in series with the resonator 2, which deteriorates the characteristics.

In addition, as shown in Fig. 2, a subtractor 6,
When the adder 7 is provided, and the gain adjustment resistor 3 shown in FIG. Since a resonator 9, that is, an equalizer section is provided in the resonator 9, an LCR resonant circuit or a tuned amplifier circuit must be used as the resonator 9. The LCR resonant circuit is structurally susceptible to external influences, and there is a problem with L used at low frequencies. Further, the tuned amplifier circuit has a disadvantage that the circuit configuration is complicated and the number of constituent elements is large.

Furthermore, even if you want to use a semiconductor resonator using an operational amplifier as shown in Figure 3 A and B, the resonant impedance Zon of the resonator is used to act as the input impedance (between the input terminal and ground) of the semiconductor resonant circuit. Can not do it.

The present invention has been made to eliminate such drawbacks, and will be described below with reference to an embodiment shown in FIG.
7, 8, 81, and 82 are the same as those in Fig. 2. The difference is that semiconductor resonators are used as 101 and 102, the midpoint N of the semiconductor resonator power supply 11 is connected to the output circuit of the subtractor 6 as a common line for the semiconductor resonator 10, and the resonator 10, including the power supply 11, is in a floating state. In other words, the power supply for the resonator 10 is a separate power supply from the subtractor 6 and adder 7, and a semiconductor resonator with a resonance characteristic in the input impedance between the input terminal and the common line can be used.

Therefore, the resistance value of the gain adjustment resistor 8 can be made small so as not to affect the resonator impedance, so that graphic equalizer characteristics can be obtained.

As is clear from the above embodiments, according to the present invention, a semiconductor resonant circuit can be used and any equalizer characteristics can be set.

[Brief explanation of the drawing]

1 and 2 are connection diagrams of conventional equalizer circuit devices, FIG. 3 A and B are connection diagrams of semiconductor resonant circuits, and FIG. 4 is a connection diagram of an equalizer circuit device according to an embodiment of the present invention. be. 6...Subtractor, 7...Adder, 8...Gain adjustment resistor, 10...Semiconductor resonator, 11...Power source.

Claims (1)

[Scope of utility model registration request] A subtracter and an adder are connected in series between the input and output terminals, a gain adjustment resistor is provided between the input terminals of the subtracter and the adder, the input is connected to the resistor, and the common line is connected to the output side of the subtracter. An equalizer circuit device comprising: a semiconductor resonant circuit connected to the subtracter and the adder; and a midpoint of a dedicated power source for the semiconductor resonant circuit, which is different from the power sources for the subtracter and the adder, connected to the common line.