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参数资料
| 型号： | AD6620AS |
| 厂商： | ANALOG DEVICES INC |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | 65 MSPS Digital Receive Signal Processor |
| 中文描述： | SPECIALTY MICROPROCESSOR CIRCUIT, PQFP80 |
| 封装： | PLASTIC, QFP-80 |
| 文件页数： | 42/43页 |
| 文件大小： | 354K |
| 代理商： | AD6620AS |
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AD6620
–42–
REV. 0
For most narrow-band uses of the AD6600/AD6620 combina-
tion, a high oversampling ratio is desired. This spreads the
quantization noise of the A/D over a wider spectrum and allows
the digital filtering of the AD6620 to remove much of this noise.
This effectively increases the SNR of the AD6600. This process
of oversampling and digital filtering is called “process gain” and
its contribution to SNR can be calculated from the equation
below.
PG
Sample Rate of Channel
Signal Bandwidth
_
=
10log
_
_
_
The process of oversampling can also provide the benefit of
lowering the noise floor of the A/D. This can increase the effec-
tive dynamic range of a receiver if the sampling rate is chosen
such that the signal harmonics and/or intermodular distortion
(IMD) products fall out of the band of interest. In this case
these spurs could be filtered by the AD6620 and the quantiza-
tion noise would be the dominant dynamic range limitation of
the AD6600/AD6620 receiver solution.
A DSP is then used to perform the demodulation of the digital
channel. This has the advantage of allowing for in-system con-
figuration options and can even allow for improved modulation
techniques to be applied in the future. This assumes that the
AD6600 and the circuitry on its front end are compatible with
the modulation standard to be used.
For more information on using the AD6600 and AD6620 in a
Single Carrier application, refer to Analog Devices’ Application
note AN-502.
Using the AD6620 in a Wideband System
The AD6620 is fully capable of being utilized in a wide-band
architecture system where A/Ds such as the AD6640 or the
AD9042 usually run at higher sample rates than those typically
found in a narrow-band system. A correspondingly wider band
can then be digitized. The digitization of this wide bandwidth
allows many more channels to be digitized using the same A/D
and IF circuitry. The core configuration of such a system is
shown in Figure 62.
INPUT
12 DATA BITS
ENCODE
SCLK
SDI
SDO
SDFS
IN[15...5]
AD6620
CLK
AD6640
SCLK
SDO
SDI
SDFS
DSP
Figure 62. Implementation of a Multicarrier Receivers
The AD6640 and the AD6620 are both designed to run as fast
as 65 MHz. In these applications the AD6620 will be used to
process only one channel and will process the data at the A/D
sample rate. Additional channels can be processed by taking the
AD6640 high speed data stream to additional AD6620s. Each
AD6620 can then be tuned to a different channel.
The AD6620 provides a great deal of selectivity by mixing down
a channel of interest as in the narrow-band case and filtering the
out-of-band noise and adjacent channels. Unlike the narrow-
band solutions it is much more difficult to place the spurious
content out of the band of interest because more of this band-
width is used due to the larger number of carrier channels. The
aliased spurs of one channel are likely to fold back on another
channel. This places a greater requirement on the Spurious
Free Dynamic Range (SFDR) of the A/D than in the narrow-
band case. The SFDR is then usually the limiting factor of the
wide-band system.
Provided that the A/D has sufficient SFDR for the air interface
requirements, the AD6620 can use process gain, as in the narrow-
band case, by filtering the out-of-band noise and adjacent chan-
nel power. This increases the SNR of the digital data stream.
As in the Narrow-band System a DSP is then used to demodu-
late the digital data. The same advantages of flexibility exist in
the wide-band case as they did in the narrow-band case. Future
improvements in demodulation algorithms can be implemented
in the receiver, provided that the front end hardware is compat-
ible with the desired modulation standard.
相关PDF资料 |
PDF描述 |
|---|---|
| AD6620S | 65 MSPS Digital Receive Signal Processor |
| AD6620 | 65 MSPS Digital Receive Signal Processor(采样速率65MSPS的数字接收信号处理器) |
| AD6622AS | Four-Channel, 75 MSPS Digital Transmit Signal Processor TSP |
| AD6622PCB | Four-Channel, 75 MSPS Digital Transmit Signal Processor TSP |
| AD6622S | Four-Channel, 75 MSPS Digital Transmit Signal Processor TSP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD6620AS-REEL | 制造商:Analog Devices 功能描述:Signal Processor 80-Pin PQFP T/R |
| AD6620ASZ | 功能描述:IC DGTL RCVR DUAL 67MSPS 80-PQFP RoHS:是 类别:集成电路 (IC) >> 接口 - 专用 系列:- 特色产品:NXP - I2C Interface 标准包装:1 系列:- 应用:2 通道 I²C 多路复用器 接口:I²C，SM 总线 电源电压:2.3 V ~ 5.5 V 封装/外壳:16-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:16-TSSOP 包装:剪切带 (CT) 安装类型:表面贴装 产品目录页面:825 (CN2011-ZH PDF) 其它名称:568-1854-1 |
| AD6620ASZ-REEL | 功能描述:IC DGTL RCVR DUAL 67MSPS 80-PQFP RoHS:是 类别:集成电路 (IC) >> 接口 - 专用 系列:- 特色产品:NXP - I2C Interface 标准包装:1 系列:- 应用:2 通道 I²C 多路复用器 接口:I²C，SM 总线 电源电压:2.3 V ~ 5.5 V 封装/外壳:16-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:16-TSSOP 包装:剪切带 (CT) 安装类型:表面贴装 产品目录页面:825 (CN2011-ZH PDF) 其它名称:568-1854-1 |
| AD6620PCB | 制造商:AD 制造商全称:Analog Devices 功能描述:65 MSPS Digital Receive Signal Processor |
| AD6620S | 制造商:AD 制造商全称:Analog Devices 功能描述:65 MSPS Digital Receive Signal Processor |
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