STK301-090 查看數據表（PDF） - SANYO -> Panasonic

零件编号

产品描述 (功能)

比赛名单

STK301-090

7-Band, 2-Channel Electronic Graphic Equalizer

SANYO -> Panasonic 

STK301-090

The LC7522 band filter connection pins, f(1) to f(7), are

used. The center frequency corresponding to each band is

shown below.

Pin name

f(1)

f(2)

f(3)

f(4)

f(5)

f(6)

f(7)

Frequency

60Hz

150Hz

400Hz

1kHz

2.5kHz

6kHz

15kHz

Figure 2. Resonant circuit

A 1MΩ resistor is connected from each pin to 1/2 VCC1 to

prevent pop noise when switching.

Flat Response, Boost and Cut

The built-in resonant and electronic volume control cir-

cuits are changed to vary the gain for the corresponding

resonant frequency. An equivalent circuit for the sake of

explanation is shown in Figure 3. Z represents the imped-

ance of the resonant circuit shown in Figure 2.

Z is the resonant circuit impedance.

VR is the LC7522 IC.

Figure 3. Equivalent circuit

Flat Response

Resistor equivalent circuit (1 band only shown)

The graphic equalizer circuit comprises 7 resonant circuits

and an output buffer amplifier (per channel). The variable

resistor (LC7522) and resonant circuit capacitors C1 and

C2 are built-in. The resonant circuits, employing semicon-

ductor inductor elements, use resonance to reduce imped-

ance and thereby change the gain.

Resonant Circuit

The resonant circuit uses semiconductor inductors, formed

by RC elements buffered by op-amp and transistor active

elements, to form an equivalent RLC series-resonant cir-

cuit. The STK301-090 resonant circuit buffer is formed by

the transistor as shown in Figure 2.

The resonant frequency fO is given by:

fO

=

-----------------------------1------------------------------

2π C1 × C2 × R1 × R2

When the volume control is set to the center position and

if Ri = RNF and the following relationships are estab-

lished:

ei′ = R-----i--R-+----⁄-R-2----⁄---2- × ei

AV = R-----N---F-R----+-⁄---2R------⁄--2--

In this case,

eo = AV × ei′ = ei

so that the gain is independent of the resonant circuit and

the frequency response becomes flat. If the maximum VR

resistance is R, the resistance value at the center position is

R/2.

No. 4589—6/9

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