AD6674 datasheet(38/91 Pages) AD

38 / 91 page

AD6674

Data Sheet

NCO

MIXER

(OPTIONAL)

DDC 3

SYSREF

REAL/I

REAL/Q

REAL/I

CONVERTER 6

Q CONVERTER 7

NCO

MIXER

(OPTIONAL)

DDC 0

SYSREF±

REAL/I

REAL/Q

REAL/I

CONVERTER 0

Q CONVERTER 1

NCO

MIXER

(OPTIONAL)

DDC 1

SYSREF±

REAL/I

REAL/Q

REAL/I

CONVERTER 2

Q CONVERTER 3

NCO

MIXER

(OPTIONAL)

DDC 2

SYSREF±

REAL/I

REAL/Q

REAL/I

CONVERTER 4

Q CONVERTER 5

ADC

SAMPLING

REAL/I

ADC

SAMPLING

REAL/I

SYNCHRONIZATION

CONTROL CIRCUITS

SYSREF±

Figure 99. DDC Detailed Block Diagram

Figure 100 shows an example usage of one of the four DDC

blocks with a real input signal and four half-band filters (HB4 +

HB3 + HB2 + HB1). It shows both complex (decimate by 16)

and real (decimate by 8) output options.

When DDCs have different decimation ratios, the chip

decimation ratio (Register 0x201) must be set to the lowest

decimation ratio of all the DDC blocks. In this scenario,

samples of higher decimation ratio DDCs are repeated to match

the chip decimation ratio sample rate. Whenever the NCO

frequency is set or changed, the DDC soft reset must be issued.

If the DDC soft reset is not issued, the output may potentially

show amplitude variations.

Table 11, Table 12, Table 13, Table 14, and Table 15 show the

DDC samples when the chip decimation ratio is set to 1, 2, 4, 8,

or 16, respectively. When DDCs have different decimation

ratios, the chip decimation ratio must be set to the lowest

decimation ratio of all the DDC channels. In this scenario,

samples of higher decimation ratio DDCs are repeated to match

the chip decimation ratio sample rate.

Rev. B | Page 38 of 91

AD6674 Datasheet(PDF) 38 Page - Analog Devices

AD6674 Datasheet(HTML) 38 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 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91

Datasheet Download

Link URL