AD1953YSTZRL Datasheet AD1953YSTZRL, AD1953YSTZ, AD1953YSTZRL7 | P34-P35

AD1953

–33–

APPENDIX

Cookbook Formulae for Audio EQ Biquad Coefficients

(adapted from Robert Bristow-Johnson’s Internet posting)

For designing a Parametric EQ, follow the steps below.

1. Given:

Frequency

dB_Gain

sample_rate

2. Compute Intermediate Variables

A = 10^(dB_Gain/40)

omega = 2

Frequency/Sample_Rate

sn = sin(omega)

cs = cos(omega)

alpha = sn/(2

3. Compute Coefficients

b0 = (1 + A

alpha)/(1 + (alpha/A))

b1 = –2

cs/(1 + (alpha/A))

b2 = (1 – (alpha/A))/(1 + (alpha/A))

a1 = 2

cs/(1 + (alpha/A)) = –b1

a2 = –(1 – (alpha/A))/(1 + (alpha/A))

4. The transfer function implemented by the AD1953 is given by:

H(Z) = (b0 + b1

–1

+ b2

–2

)/(1 – a1

–1

– a2

–2

)

Note the inversion in sign of a1 and a2 relative to the more standard form. This form is used in this document because the AD1953

implements the difference equation using the formula below.

Y(n) = a1

y(n – 1) + a2

y(n – 2) + b0

x(n) + b1

x(n – 1) + b2

x(n – 2)

REV. A

AD1953

Rev. A | Page 34

OUTLINE DIMENSIONS

COMPLIANT TO JEDEC STANDARDS MS-026-BBC

TOP VIEW

(PINS DOWN)

0.27

0.22

0.17

0.50

BSC

LEAD PITCH

1.60

MAX

0.75

0.60

0.45

VIEW A

PIN 1

0.20

0.09

1.45

1.40

1.35

0.08

COPLANARITY

VIEW A

ROTATED 90° CCW

SEATING

PLANE

7°

3.5°

0°

0.15

0.05

9.20

9.00 SQ

8.80

7.20

7.00 SQ

6.80

051706-A

Figure 25. 48-Lead Low Profile Quad Flat Package [LQFP]

(ST-48)

Dimensions shown in millimeters

ORDERING GUIDE

Model

Temperature Range Package Description Package Option

AD1953YSTZ –40°C to +105°C 48-Lead LQFP ST-48

AD1953YSTZRL –40°C to +105°C 48-Lead LQFP ST-48 on 13" Reel

Z = RoHS Compliant Part.

registered trademarks are the property of their respective owners.

D02909-0-12/14(A)

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P18 P19-P21 P22-P24 P25-P27 P28-P30 P31-P33 P34-P35

AD1953YSTZRL

Mfr. #:

Buy AD1953YSTZRL

Manufacturer:

Analog Devices Inc.

Description:

Audio DSPs IC Digital Audio Processor

Lifecycle:

New from this manufacturer.

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AD1953YSTZRL

AD1953YSTZRL

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