AD9852ASQZ datasheet(25/52 Pages) AD

25 / 52 page

AD9852

Rev. E | Page 25 of 52

CLR ACC2

FREQUENCY

MODE

TW1

DPW

000 (DEFAULT)

RAMP RATE

011 (CHIRP)

I/O UD CLK

Figure 43. Effect of CLR ACC2 in FM Chirp Mode

HOLD

FREQUENCY

MODE

TW1

DFW

000 (DEFAULT)

RAMP RATE

011 (CHIRP)

DELTA FREQUENCY WORD

RAMP RATE

I/O UD CLK

Figure 44. Example of Hold Function

The 32-bit automatic I/O update counter can be used to

construct complex chirp or ramped FSK sequences. Because

this internal counter is synchronized with the AD9852 system

clock, it allows precisely timed program changes to be invoked.

For such changes, the user need only reprogram the desired

registers before the automatic I/O update clock is generated.

In chirp mode, the destination frequency is not directly speci-

fied. If the user fails to control the chirp, the DDS automatically

confines itself to the frequency range between dc and Nyquist.

Unless terminated by the user, the chirp continues until power

is removed.

When the chirp destination frequency is reached, the user can

choose any of the following actions:

•

Stop at the destination frequency either by using the

HOLD pin or by loading all 0s into the delta frequency

word registers of the frequency accumulator (ACC1).

•

Use the HOLD pin function to stop the chirp, and then ramp

down the output amplitude either by using the digital multi-

plier stages and the output shaped keying pin (Pin 30) or by

using the program register control (Address 21 hex to

Address 24 hex).

•

Abruptly end the transmission with the CLR ACC2 bit.

AD9852ASQZ 数据表(PDF) 25 Page - Analog Devices

AD9852ASQZ 数据表(HTML) 25 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

数据表下载

链接网址

AD9852ASQZ 数据表(PDF) 25 Page - Analog Devices

AD9852ASQZ 数据表(HTML) 25 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

数据表 下载

链接网址

数据表下载