Bass Band Circuit

This section presents the equivalent circuit and the calculations for the external capacitors and resistors used to achieve a

center frequency of 100 Hz.

• Bass band equivalent circuit

• Sample calculation

Specifications

Center frequency: f0 = 100 Hz

Gain at maximum boost: G = 20 dB

Let R1 = 0, R2 = 66.6 K

Ω, and C1 = C2 = C.

(1) Determine R2 from the fact that G = 20 dB.

R2

2R3

R2

66000

R3 = ———————— = —————

≠ 3.7 kΩ

2

× (10 – 1)

(2) Determine C from the fact that the center frequency f0 = 100 Hz.

1

f 0 = ————————

2

π R3R2C1C2

11

C = —————— = ———————————

≠ 0.1 µF

2

πf 0 R3R22π × 100 66000 × 3700

(3) Determine Q.

R3R2

1

Q = ——— • ———

≠ 2.1

2R3

R3R2

• Treble band circuit

The treble band circuit provides shelving characteristics.

This section presents the equivalent circuit in boost mode and the formulas used to calculate the external component

values.

No. 6270-17/20

LC75341, 75341M

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