STA320

8/37

Table 9.

5.1.2 Interpolation Ratio Select

The STA320 has variable interpolation (oversampling) settings such that internal processing and DDX output

rates remain consistent. The first processing block interpolates by either 2 times or 1 time (pass-through). or

provides a 2 times downsample.

The IR bits determine the oversampling ratio of this interpolation.

IR bit settings as a function of Input Sample Rate

Table 10.

Example: IR = 00, MCS = 011 (Default value):

XTI = 256 x fs = 8.192MHz (fs=32KHz) or 11.2896MHz (fs=44.1KHz) or 12.288MHz (fs=48KHz)

5.1.3 Thermal Warning Recovery Bypass

If the Thermal Warning Adjustment is enabled (TWAB=0), then the Thermal Warning Recovery will deter-

mine if the -3dB adjustment is removed when Thermal Warning is negative. If TWRB=0 and TWAB=0,

then when a thermal warning disappears the -3dB adjustment will be removed and the gain will be added

back to the system.

If TWRB=1 and TWAB=0, then when a thermal warning disappears the -3dB adjustment will remain until

TWRB is changed to zero or the device is reset.

Input Sample Rate

IR

MCS(2..0)

000

001

010

011

100

101

32, 44.1, 48

00

768fs

512fs

384fs

256fs

128fs

576fs

88.2, 96

01

384fs

256fs

192fs

128fs

64fs

x

176.4, 192

1X

384fs

256fs

192fs

128fs

64fs

x

BIT

R/W

RST

NAME

DESCRIPTION

4..3

R/W

00

IR(1..0)

Interpolation Ratio Select: Selects internal interpolation ratio

Input Sample Rate

IR(1,0)

32

00

2 times oversampling

44.1

00

2 times oversampling

48

00

2 times oversampling

88.2

01

Pass-Through

96

01

Pass-Through

176.4

10

2 times oversampling

192

10

2 times oversampling

BIT

R/W

RST

NAME

DESCRIPTION

5

R/W

1

TWRB

Thermal-Warning Recovery Bypass:

0 - Thermal warning Recovery enabled

1 - Thermal warning Recovery disabled