TMS57014A

DUAL AUDIO DIGITAL-TO-ANALOG CONVERTER

SLAS077D – SEPTEMBER 1993 – REVISED NOVEMBER 1995

6

POST OFFICE BOX 655303

de-emphasis filter (continued)

0

10

–10

De-emphasis

3.18

(50

µs)

10.6

(15

µs)

Frequency – kHz

Figure 4. De-emphasis Characteristics

digital attenuation

A value selected in the internal attenuation register determines the attenuation of the digital-audio-data input.

The attenuation value is 11 bits long with a valid range of hex values from 400h to 000h. A data value of 001h

corresponds to an attenuation value of – 60 dB and a data value of 400h corresponds to 0 dB. The attenuation

function is nonlinear (see equation 1). Figure 5 illustrates the attenuation function in dB. The default attenuation

value is 400h.

Attenuation

+ 20 log attenuation data

1024

(1)

0

–10

–20

–30

–40

–50

–60

1024 896

768

640

512

384

256

128

0

Attenuation Data (decimal values)

Figure 5. Digital Attenuation Characteristics