数据搜索系统,热门电子元器件搜索
  Chinese▼

Delete All
ON OFF
ALLDATASHEETCN.COM

X  

预览 PDF Download HTML

DAC3484_15 Datasheet(数据表) 38 Page - Texas Instruments

部件型号  DAC3484
说明  Quad-Channel, 16-Bit, 1.25 GSPS Digital-to-Analog Converter
下载  107 Pages
Scroll/Zoom Zoom In 100% Zoom Out
制造商  TI1 [Texas Instruments]
网页  http://www.ti.com
标志 

DAC3484 Datasheet(HTML) 38 Page - Texas Instruments

Zoom Inzoom in Zoom Outzoom out
 38 page
background image
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
–160
–140
–120
–100
–80
–60
–40
–20
0
20
f/f
IN
G048
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
–160
–140
–120
–100
–80
–60
–40
–20
0
20
f/f
IN
G049
DAC3484
SLAS749E – MARCH 2011 – REVISED NOVEMBER 2015
www.ti.com
7.3.6 FIR Filters
Figure 60 through Figure 63 show the magnitude spectrum response for the FIR0, FIR1, FIR2 and FIR3
interpolating filters where fIN is the input data rate to the FIR filter. Figure 64 to Figure 67 show the composite
filter response for 2x, 4x, 8x and 16x interpolation. The transition band for all interpolation settings is from 0.4 to
0.6 x fDATA (the input data rate to the device) with <0.001dB of pass-band ripple and >90dB stop-band
attenuation.
The DAC3484 also has a 9-tap inverse sinc filter (FIR4) that runs at the DAC update rate (fDAC) that can be used
to flatten the frequency response of the sample-and-hold output. The DAC sample-and-hold output sets the
output current and holds it constant for one DAC clock cycle until the next sample, resulting in the well-known
sin(x)/x or sinc(x) frequency response (Figure 68, red line). The inverse sinc filter response (Figure 68, blue line)
has the opposite frequency response from 0 to 0.4 x Fdac, resulting in the combined response (Figure 68, green
line). Between 0 to 0.4 x fDAC, the inverse sinc filter compensates the sample-and-hold roll-off with less than
0.03dB error.
The inverse sinc filter has a gain >1 at all frequencies. Therefore, the signal input to FIR4 must be reduced from
full scale to prevent saturation in the filter. The amount of back-off required depends on the signal frequency, and
is set such that at the signal frequencies the combination of the input signal and filter response is less than 1
(0dB). For example, if the signal input to FIR4 is at 0.25 x fDAC, the response of FIR4 is 0.9dB, and the signal
must be backed off from full scale by 0.9dB to avoid saturation. The gain function in the QMC blocks can be
used to reduce the amplitude of the input signal. The advantage of FIR4 having a positive gain at all frequencies
is that the user is then able to optimize the back-off of the signal based on its frequency.
The filter taps for all digital filters are listed in Table 6. Note that the loss of signal amplitude may result in lower
SNR due to decrease in signal amplitude.
SPACER
Figure 60. Magnitude Spectrum for FIR0
Figure 61. Magnitude Spectrum for FIR1
SPACER
SPACER
38
Submit Documentation Feedback
Copyright © 2011–2015, Texas Instruments Incorporated
Product Folder Links: DAC3484




HTML 页

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  53  54  55  56  57  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72  73  74  75  76  77  78  79  80  81  82  83  84  85  86  87  88  89  90  91  92  93  94  95  96  97  98  99  100   ...More


数据表 下载




链接网址


Privacy Policy
ALLDATASHEETCN.COM
ALLDATASHEET是否为您带来帮助?  [ DONATE ]  

关于 Alldatasheet    |   广告服务   |   联系我们   |   隐私政策   |   书签   |   链接交换   |   制造商名单
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  , Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp  |   Russian : Alldatasheetru.com
Korean : Alldatasheet.co.kr   |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com  |   Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl