AD9852ASQZ datasheet(26/52 Pages) AD

26 / 52 page

AD9852

Rev. E | Page 26 of 52

•

Continue chirp by reversing the direction and returning to

the previous or another destination frequency in a linear or

user-directed manner. If this involves reducing the

frequency, a negative 48-bit delta frequency word (the

MSB is set to 1) must be loaded into Register 10 hex to

frequency word requires the MSB to be set to logic high.

•

Continue chirp by immediately returning to the beginning

frequency (F1) in a sawtooth fashion, and then repeating the

previous chirp process. In this case, an automatic repeating

chirp can be set up by using the 32-bit update clock to issue

the CLR ACC1 command at precise time intervals. Adjusting

the timing intervals or changing the delta frequency word

changes the chirp range. It is incumbent upon the user to

balance the chirp duration and frequency resolution to

achieve the proper frequency range.

BPSK (MODE 100)

Binary, biphase, or bipolar phase shift keying is a means to

rapidly select between two preprogrammed 14-bit output phase

offsets. The logic state of BPSK (Pin 29) controls the selection of

Phase Adjust Register 1 or Phase Adjust Register 2. When low,

BPSK selects Phase Adjust Register 1; when high, it selects

Phase Adjust Register 2. Figure 45 illustrates phase changes

made to four cycles of an output carrier.

Basic BPSK Programming Steps

Program a carrier frequency into Frequency Tuning Word 1.

Program the appropriate 14-bit phase words into Phase Adjust

Attach the BPSK data source to Pin 29.

Activate the I/O update clock when ready.

If higher-order PSK modulation is desired, the user can select

single-tone mode and program Phase Adjust Register 1 using

the serial or high speed parallel programming bus.

BPSK DATA

360

PHASE

MODE

FTW1

PHASE ADJUST 1

000 (DEFAULT)

PHASE ADJUST 2

100 (BPSK)

270

I/O UD CLK

Figure 45. BPSK Mode

AD9852ASQZ 数据表(PDF) 26 Page - Analog Devices

AD9852ASQZ 数据表(HTML) 26 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