AV2636

Product Datasheet

DIGITAL FILTER CHARACTERISTICS

The digital interpolation filters have small passband ripples and large stopband attenuations. There are

three types of filters that are implemented for different sample mode (1X/2X/4X) and MCK relations. The

selection of the filters depends on the operation mode of the device, auto-detect mode or programmable

mode.

Programmable mode: filter selection is shown in the following table. 20kHz audio passband is assumed.

Sample Mode

Parameter

Condition

Min

Max

Unit

Passband Ripple

F < 0.45fs

±0.03

dB

Normal (1X)

Stopband Attenuation

F > 0.55fs

60

dB

Passband Ripple

F < 0.225fs

±0.03

dB

Double (2X)

Stopband Attenuation

F > 0.775fs

60

dB

Passband Ripple

F < 0.1125fs

±0.03

dB

Quad (4X)

Stopband Attenuation

F > 0.8875fs

53

dB

Auto-detect mode: filter type is automatically selected based on the detected sample mode and MCK

relations.

The following plots show the digital filter response and closer look of the passband ripple for normal

speed mode (1X), double speed mode (2X) and quad speed (4X).

AVS Technology, Inc.

12-16

August 18, 2004

www.avstech.com