MSP58C20

AUDIO-BAND CONVERTER

SPSS015B – DECEMBER 1993 – REVISED JULY 1996

9

POST OFFICE BOX 655303

PARAMETER MEASUREMENT INFORMATION

The receive characteristics in the electrical characteristics table are measured by activating the MSP58C20 receive

path through a digital modulator. This modulator consists of two functional blocks (see Figure 1 and Figure 2)

connected in series. The output of the decoder (see Figure 2) is shown in Table 1.

Z –1

BITS (16 –1)

/

16

/

16

/

13 MSBs

3

/

Di

Em

3

/

+

3 LSBs

Figure 1. 16- to 13-Bit Modulator at 512-kHz Sampling Rate

Di

Z –1

Dx

Decoder

Z –1

DIGS

DIGL

13

/

16

/

11

/

12

/

4 MSBs

/

12

/

3

/

16

/

16

/

3

/

Ux

Vx

512 kHz

Dx

Sx

Rx

16

1/ 32

64

2048

+

+

+

+

12

512 kHz

Figure 2. Sigma-Delta-2 Modulator at 512-kHz Sampling Rate

Table 1. Dx Decoder

DECODER INPUT

DECODER OUTPUT

Vx (11)

Vx (10)

Vx (9)

Vx (8)

Dx (2)

Dx (1)

Dx (0)

DIGS

DIGL

0

1

X

X

H

H

L

L

H

0

0

1

X

H

H

L

L

H

0

0

0

1

H

H

L

L

H

0

0

0

0

H

H

H

L

L

1

1

1

1

L

L

H

H

L

1

1

1

0

L

H

L

H

H

1

1

0

X

L

H

L

H

H

1

0

X

X

L

H

L

H

H