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参数资料
| 型号： | AD9912A/PCBZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 11/40页 |
| 文件大小： | 0K |
| 描述： | BOARD EVALUATION FOR AD9912 |
| 产品培训模块： | 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 |
| 标准包装： | 1 |
| 主要目的： | 计时，直接数字合成（DDS） |
| 嵌入式： | 否 |
| 已用 IC / 零件： | AD9912 |
| 主要属性： | 14 位数模转换器，48 位调节字宽 |
| 次要属性： | 1GHz 图形用户界面 |
| 已供物品： | 板 |
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AD9912
Rev. F | Page 19 of 40
PRIMARY
SIGNAL
FILTER
RESPONSE
SIN(x)/x
ENVELOPE
SPURS
IMAGE 0
IMAGE 1
IMAGE 2
IMAGE 3
IMAGE 4
0
–20
–40
–60
–80
–100
MAGNITUDE
(dB)
fs/2
fs
3
fs/2
2
fs
5
fs/2
f
BASE BAND
06
76
3-
03
4
Figure 42. DAC Spectrum vs. Reconstruction Filter Response
Because the DAC constitutes a sampled system, its output must
be filtered so that the analog waveform accurately represents the
digital samples supplied to the DAC input. The unfiltered DAC
output contains the (typically) desired baseband signal, which
extends from dc to the Nyquist frequency (fS/2). It also contains
images of the baseband signal that theoretically extend to infinity.
Notice that the odd images (shown in Figure 42) are mirror
images of the baseband signal. Furthermore, the entire DAC
output spectrum is affected by a sin(x)/x response, which is
caused by the sample-and-hold nature of the DAC output signal.
For applications using the fundamental frequency of the DAC
output, the response of the reconstruction filter should preserve
the baseband signal (Image 0), while completely rejecting all
other images. However, a practical filter implementation
typically exhibits a relatively flat pass band that covers the
desired output frequency plus 20%, rolls off as steeply as
possible, and then maintains significant (though not complete)
rejection of the remaining images. Depending on how close
unwanted spurs are to the desired signal, a third-, fifth-, or
seventh-order elliptic low-pass filter is common.
Some applications operate off an image above the Nyquist
frequency, and those applications use a band-pass filter instead
of a low-pass filter.
The design of the reconstruction filter has a significant impact
on the overall signal performance. Therefore, good filter design
and implementation techniques are important for obtaining the
best possible jitter results.
FDBK_IN INPUTS
The FDBK_IN pins serve as the input to the comparators and
output drivers of the AD9912. Typically, these pins are used to
receive the signal generated by the DDS after it has been band-
limited by the external reconstruction filter.
A diagram of the FDBK_IN input pins is provided in Figure 43,
which includes some of the internal components used to bias
the input circuitry. Note that the FDBK_IN input pins are
internally biased to a dc level of ~1 V. Care should be taken to
ensure that any external connections do not disturb the dc bias
because this may significantly degrade performance.
06
76
3-
03
5
15k
15k
~1pF
TO S-DIVIDER
AND CLOCK
OUTPUT SECTION
AVSS
~1V
AVSS
~2pF
+
FDBK_IN
FDBK_INB
Figure 43. Differential FDBK_IN Inputs
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD9912BCPZ | 制造商:Analog Devices 功能描述:Direct Digital Synthesizer 1000MHz 1-DAC 14-Bit Serial 64-Pin LFCSP EP 制造商:Analog Devices 功能描述:DIRECT DGTL SYNTHESIZER 64LFCSP EP - Trays 制造商:Analog Devices 功能描述:IC DDS 1GSPS 14BIT DAC |
| AD9912BCPZ-REEL7 | 制造商:Analog Devices 功能描述:DIRECT DGTL SYNTHESIZER 64LFCSP EP - Tape and Reel |
| AD9913 | 制造商:AD 制造商全称:Analog Devices 功能描述:Low Power 250 MSPS 10-Bit DAC 1.8 V CMOS Direct Digital Synthesizer |
| AD9913/PCBZ | 功能描述:数据转换 IC 开发工具 Sub 50mW 250MSPS (+) 10-bit DDS RoHS:否 制造商:Texas Instruments 产品:Demonstration Kits 类型:ADC 工具用于评估:ADS130E08 接口类型:SPI 工作电源电压:- 6 V to + 6 V |
| AD9913/PCBZ1 | 制造商:AD 制造商全称:Analog Devices 功能描述:Low Power 250 MSPS 10-Bit DAC 1.8 V CMOS Direct Digital Synthesizer |
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