參數(shù)資料
型號(hào): AD9953
廠商: Analog Devices, Inc.
元件分類: XO, clock
英文描述: 400 MSPS 14-Bit, 1.8V CMOS Direct Digital Synthesizer
中文描述: 400 MSPS的14位,1.8V CMOS的直接數(shù)字頻率合成器
文件頁(yè)數(shù): 10/42頁(yè)
文件大?。?/td> 473K
代理商: AD9953
PRELIMINARY TECHNICAL DATA
Theory of Operation
AD9953
Component Blocks
DDS Core
The output frequency (f
o
) of the DDS is a function of the frequency of system clock (
SYSCLK
),
the value of the frequency tuning word (FTW), and the capacity of the accumulator (2
32
, in this
case). The exact relationship is given below with f
s
defined as the frequency of SYSCLK.
f
o
= (FTW)(f
s
) / 2
32
{ 0
FTW
2
31
f
o
= f
s*
( 1 – ( FTW / 2
32
) ) { 2
31
< FTW < 2
32
-1
The AD9953 frequency tuning word(s) are unsigned numbers, where 80000000(hex) represents
the highest output frequency possible, commonly referred to as the Nyquist frequency. Values
ranging from than 80000001(hex) to FFFFFFFF (hex) will be expressed as aliased frequencies less
than Nyquist. An example using a 3-bit phase accumulator will illustrate this principle. For a
tuning word of 001, the phase accumulator output (PAO) increments from all zeros to all ones and
repeats when the accumulator overflows after clock cycle number 8. For the tuning word of 111,
the phase accumulator output (PAO) decrements from all ones to all zeros and repeats when the
accumulator overflows after clock cycle number 8. While the phase accumulator outputs are
“reversed” with respect to clock cycles, the outputs provide identical inputs to the phase to
amplitude converter, which means the DDS output frequencies are identical.
Mathematically, for a 3-bit accumulator, the following equations apply:
f
o
= f
s*
(FTW / 2
3
)
{ 0
FTW
2
2
f
o
= f
s*
( 1 – ( FTW / 2
3
) ) { 2
2
< FTW < 2
3
-1
For the 001 frequency tuning word:
Fout = Fs * 1/2
3
= 1/8*Fs
And for the 111 frequency tuning word:
Fout = Fs * (1 – 7/8) = 1/8*Fs
The value at the output of the Phase Accumulator is translated to an amplitude value via the
COS(x) functional block and routed to the DAC.
REV. PrB 1/30/03
Page 10
Analog Devices, Inc.
相關(guān)PDF資料
PDF描述
AD9953ASV 400 MSPS 14-Bit, 1.8V CMOS Direct Digital Synthesizer
AD9953PCB 400 MSPS 14-Bit, 1.8V CMOS Direct Digital Synthesizer
AD9954 400 MSPS 14-Bit, 1.8 V CMOS Direct Digital Synthesizer
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD9953/PCB 制造商:Analog Devices 功能描述:400 MSPS, 14BIT DGTL SYNTHESIZER - Bulk
AD9953ASV 制造商:AD 制造商全稱:Analog Devices 功能描述:400 MSPS 14-Bit, 1.8V CMOS Direct Digital Synthesizer
AD9953PCB 制造商:AD 制造商全稱:Analog Devices 功能描述:400 MSPS 14-Bit, 1.8V CMOS Direct Digital Synthesizer
AD9953YSV 制造商:Analog Devices 功能描述:Direct Digital Synthesizer 400MHz 1-DAC 14-Bit Serial 48-Pin TQFP EP 制造商:Rochester Electronics LLC 功能描述:AD9953 400 MSPS DDS W/ 14 BIT DAC - Bulk 制造商:Analog Devices 功能描述:IC DDS 400MSPS SMD 9953 TQFP48
AD9953YSV-REEL7 制造商:Analog Devices 功能描述:Direct Digital Synthesizer 400MHz 1-DAC 14-Bit Serial 48-Pin TQFP EP T/R