AD9957SLASHPCBZ datasheet(22/61 Pages) AD

22 / 61 page

AD9957

Data Sheet

Rev. F | Page 22 of 61

tDH

TxENABLE

PDCLK

D[17:0]

IK – 1

tDH

tDS

Figure 30. 18-Bit Parallel Port Timing Diagram—Interpolating DAC Mode

tDH

TxENABLE

PDCLK

D[17:0]

tDH

tDS

Figure 31. 18-Bit Parallel Port Timing Diagram—Quadrature Modulation Mode

TxENABLE

PDCLK

I DATA

Q DATA

Q10

Q11

Q12

Q13

Q14

Q15

I10

I11

I12

I13

I14

I15

I16n – 1

Q16n – 1

Figure 32. Dual Serial I/Q Bit Stream Timing Diagram, BFI Mode

INPUT DATA ASSEMBLER

The input to the AD9957 is an 18-bit parallel data port in

QDUC mode or interpolating DAC mode. In BFI mode, it

operates as a dual serial data port.

In QDUC mode, it is assumed that two consecutive 18-bit

words represent the real (I) and imaginary (Q) parts of a

complex number of the form, I + jQ. The 18-bit words are

supplied to the input of the AD9957 at a rate of

SYSCLK

PDCLK

for QDUC mode

where:

fSYSCLK (for all of the PDCLK equations in this section) is the

sample rate of the DAC.

R (for all of the PDCLK equations in this section) is the

interpolation factor of the programmable interpolation filter.

When the PDCLK rate control bit is active in QDUC mode,

however, the frequency of PDCLK becomes

SYSCLK

PDCLK

with PDCLK rate control active

In the interpolating DAC mode, the rate of PDCLK is the same

as QDUC mode with the PDCLK rate control bit active, that is,

SYSCLK

PDCLK

for interpolating DAC mode

In BFI mode, the 18-bit parallel input converts to a dual serial

input that is, one pin is assigned as the serial input for the I-words

and one pin is assigned as the serial input for the Q-words. The

other 16 pins are not used. Furthermore, each I- and Q-word

has a 16-bit resolution. fPDCLK is the bit rate of the I- and Q-data

streams and is given by

SYSCLK

PDCLK =

for BFI mode

AD9957/PCBZ 数据表(PDF) 22 Page - Analog Devices

AD9957/PCBZ 数据表(HTML) 22 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61

数据表下载

链接网址

AD9957/PCBZ 数据表(PDF) 22 Page - Analog Devices

AD9957/PCBZ 数据表(HTML) 22 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61

数据表 下载

链接网址

数据表下载