參數(shù)資料
型號： AD9709-EB
廠商： Analog Devices, Inc.
英文描述： 8-Bit, 125 MSPS Dual TxDAC D/A Converter
中文描述： 8位，125 MSPS的TxDAC系列雙D / A轉(zhuǎn)換
文件頁數(shù)： 17/27頁
文件大?。?/td> 466K
代理商： AD9709-EB
REV. 0
AD9709
–17–
CDMA
Carrier Division Multiple Access, or CDMA, is an air transmit/
receive scheme where the signal in the transmit path is modulated
with a pseudorandom digital code (sometimes referred to as the
spreading code). The effect of this is to spread the transmitted
signal across a wide spectrum. Similar to a DMT waveform, a
CDMA waveform containing multiple subscribers can be char-
acterized as having a high peak to average ratio (i.e., crest factor),
thus demanding highly linear components in the transmit signal
path. The bandwidth of the spectrum is defined by the CDMA
standard being used, and in operation is implemented by using
a spreading code with particular characteristics.
Distortion in the transmit path can lead to power being trans-
mitted out of the defined band. The ratio of power transmitted
in-band to out-of-band is often referred to as Adjacent Channel
Power (ACP). This is a regulatory issue due to the possibility
of interference with other signals being transmitted by air.
Regulatory bodies define a spectral mask outside of the transmit
band, and the ACP must fall under this mask. If distortion in
the transmit path causes the ACP to be above the spectral mask,
then filtering, or different component selection is needed to
meet the mask requirements.
Figure 42 shows the AD9709/AD8346 application circuit of
Figure 41 reconstructing a wideband, or W-CDMA test vector
with a bandwith of 8 MHz, centered at 2.4 GHz and being
sampled at 62.5 MHz. The IF frequency at the DAC output
is 15.625 MHz. ACPR for the given test vector is measured
at greater than 54 dB.
FREQUENCY
CENTER 2.4GHz 3MHz SPAN 30MHz
cu1
c11
–
130
–
120
–
110
–
100
–
90
–
80
–
70
–
60
–
50
–
40
–
30
d
1
C2
C0
c11
Figure 42. CDMA Signal, 8 M Chips Sampled at 65 MSPS,
Recreated at 2.4 GHz, Adjacent Channel Power > 54 dBm
Figure 43 shows an example of the AD9709 used in a W-CDMA
transmitter application using the AD6122 CDMA 3V IF sub-
system. The AD6122 has functions, such as external gain
control and low-distortion characteristics, needed for the
superior Adjacent Channel Power (ACP) requirements of
W-CDMA.
(
“
Q DAC
”
)
IOUTA
QOUTA
QOUTB
DCOM
FSADJ2
REFIO
SLEEP
R
1.9k
0.1 F
CLK2
Q DATA
INPUT
I DATA
INPUT
DVDD
AVDD
500
50
500
500
IIPP
IIPN
IIQP
IIQN
AD6122
CLK1
FSADJ1
R
SET1
2k
R
CAL
220
500
50
DAC
LATCH
DAC
(
“
I DAC
”
)
INPUT
LATCHES
WRT1
WRT2
ACOM
AD9709
U1
U2
LOIPP
LOIPN
2
PHASE
SPLITTER
REFIN
VGAIN
GAIN
CONTROL
TXOPP
TXOPN
GAIN
CONTROL
SCALE
FACTOR
TEMPERATURE
COMPENSATION
MODOPN
MODOPP
V
CC
V
CC
3V
500
500
IOUTB
INPUT
LATCHES
500
50
500
50
DAC
LATCH
DAC
634
Figure 43. CDMA Transmit Application Using AD9709 and AD6122
相關(guān)PDF資料
PDF描述
AD9712B RES,0.0,0.25W,METAL FILM,0%
AD9712BAN RES,0.0,0.25W,METAL FILM,0%
AD9712BAP TEST POINT, WHITE, 0.040 HOLE, 0.062 PCB
AD9712BBN POWER JACK, 250V,2 COND. FEMALE,2.1MM
AD9712BBP 12-Bit, 100 MSPS D/A Converters
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD9709-EBZ 功能描述:BOARD EVAL FOR AD9709 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 數(shù)模轉(zhuǎn)換器 (DAC) 系列:TxDAC® 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- DAC 的數(shù)量:4 位數(shù):12 采樣率（每秒）:- 數(shù)據(jù)接口:串行，SPI? 設(shè)置時間:3µs DAC 型:電流/電壓 工作溫度:-40°C ~ 85°C 已供物品:板 已用 IC / 零件:MAX5581
AD9709-EBZ1 制造商:AD 制造商全稱:Analog Devices 功能描述:8-Bit, 125 MSPS, Dual TxDAC Digital-to-Analog Converter
AD9712 制造商:AD 制造商全稱:Analog Devices 功能描述:12-BIT, 100MSPS D/A CONVERTERS
ad97128bsq/883b 制造商:Analog Devices 功能描述:
AD9712AJN 制造商:未知廠家 制造商全稱:未知廠家 功能描述:12-Bit Digital-to-Analog Converter
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