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參數(shù)資料
| 型號： | AD9858/PCBZ |
| 廠商： | Analog Devices Inc |
| 文件頁數(shù)： | 10/32頁 |
| 文件大?。?/td> | 0K |
| 描述： | BOARD EVAL FOR AD9858 |
| 產(chǎn)品培訓(xùn)模塊： | Direct Digital Synthesis Tutorial Series (1 of 7): Introduction Direct Digital Synthesizer Tutorial Series (7 of 7): DDS in Action Direct Digital Synthesis Tutorial Series (3 of 7): Angle to Amplitude Converter Direct Digital Synthesis Tutorial Series (6 of 7): SINC Envelope Correction Direct Digital Synthesis Tutorial Series (4 of 7): Digital-to-Analog Converter Direct Digital Synthesis Tutorial Series (2 of 7): The Accumulator |
| 設(shè)計資源： | Low Jitter Sampling Clock Generator for High Performance ADCs Using AD9958/9858 and AD9515 (CN0109) |
| 標(biāo)準包裝： | 1 |
| 主要目的： | 計時，直接數(shù)字合成（DDS） |
| 已用 IC / 零件： | AD9858/TL |
| 已供物品： | 板 |
| 其它名稱： | AD9858/PCB AD9858/PCB-ND |
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AD9858
Rev. C | Page 18 of 32
A DFRRW value of 0 written to the register stops all frequency
sweeping. There is no automated stop-at-a-given-frequency
function. The user must calculate the time interval required to
reach the final frequency and then issue a command to write 0
into the DFRRW register. The time required for a frequency
sweep is calculated by
DFTW
DFRRW
SYSCLK
2
f
t
2
34
S
F
×
=
where:
T is the duration of the sweep in seconds.
fS is the starting frequency determined by
SYSCLK
2
FTW
f
32
S
×
=
fF is the final frequency.
The delta frequency step size is given by
31
2
SYSCLK
DFTW ×
=
Δf
,
remembering that DFTW is a signed (twos complement) value.
The time between each frequency step (Δt) is given by
SYSCLK
DFRRW
×
= 8
Δt
The value of the stop frequency fF is determined by
Δt
Δf
×
+
=
t
f
S
F
Returning to Starting Frequency
The original frequency tuning word (FTW), which is written into
the frequency tuning register, does not change at any time during
a sweep operation. This means that the DDS can return to the
sweep starting frequency at any time during a sweep. Setting the
control bit, autoclear frequency accumulator, forces the frequency
accumulator to 0, instantly returning the DDS to the frequency
stored as FTW.
Full Sleep Mode
Setting all of the power-down bits in the control function register
activates full sleep mode. During the power-down condition,
the clocks associated with the various functional blocks of the
device are turned off, thereby offering a significant power savings.
SYNCHRONIZATION
SYNCLK and FUD Pins
Timing for the AD9858 is provided via the user-supplied REFCLK
input. The REFCLK input is buffered and is the source for the
internally generated SYSCLK. The frequency of SYSCLK can be
either the same as REFCLK or half that of REFCLK (CFR[6]).
The REFCLK input is capable of handling input frequencies as
high as 2 GHz. However, the device is designed for a maximum
SYSCLK frequency of 1 GHz. Thus, it is mandatory that the
divide-by-2 SYSCLK function be enabled when the frequency
of REFCLK is greater than 1 GHz.
SYSCLK serves as the sample clock for the DAC and is fed to
a divide-by-8 frequency divider to produce SYNCLK. SYNCLK
is provided to the user on the SYNCLK pin. This enables
synchronization of external hardware with the internal DDS
clock of the AD9858. External hardware that is synchronized
to the SYNCLK signal can then be used to provide the frequency
update (FUD) signal to the AD9858. The FUD signal and
SYNCLK are used to transfer the internal buffer register
contents into the memory registers of the device. Figure 33
shows a block diagram of the synchronization methodology,
and Figure 34 shows an I/O synchronization timing diagram.
SYNCLK is also used to synchronize the assertion of the profile
select pins (PS0 and PS1). The FUD, PS0, and PS1 pins must be
set up and held around the rising edge of SYNCLK.
U
P
DA
T
E
RE
G
S
REGISTER
MEMORY
EDGE
DETECTION
LOGIC
REFCLK
PS0, PS1
FUD
SYNCLK
SYSCLK
0
2 GHz DIVIDER
DISABLE
SYNCLK
DISABLE
TO CORE LOGIC
BUFFER
MEMORY
÷ 2
10
D
Q
WR/SCLK
ADDRx
DATA
SYNCLK
D
Q
÷ 8
03
16
6-
03
6
Figure 33. I/O Synchronization Block Diagram
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AD9858TLPCB | 制造商:AD 制造商全稱:Analog Devices 功能描述:1 GSPS Direct Digital Synthesizer |
| AD9858XSV | 制造商:Analog Devices 功能描述: |
| AD9859 | 制造商:AD 制造商全稱:Analog Devices 功能描述:400 MSPS, 10-Bit, 1.8 V CMOS Direct Digital Synthesizer |
| AD9859/PCB | 制造商:Analog Devices 功能描述:NCO, 400MSPS 10 BIT, 1.8V CMOS DIRECT DGTL SYNTHESIZER - Bulk |
| AD9859/PCBZ | 功能描述:BOARD EVAL FOR AD9859 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估演示板和套件 系列:AgileRF™ 標(biāo)準包裝:1 系列:- 主要目的:電信，線路接口單元（LIU） 嵌入式:- 已用 IC / 零件:IDT82V2081 主要屬性:T1/J1/E1 LIU 次要屬性:- 已供物品:板，電源，線纜，CD 其它名稱:82EBV2081 |
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