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參數資料
| 型號： | AD9864 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | IF Digitizing Subsystem |
| 中文描述： | 中頻數字化子系統 |
| 文件頁數： | 9/44頁 |
| 文件大?。?/td> | 1984K |
| 代理商： | AD9864 |
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AD9864
DEFINITION OF SPECIFICATIONS/TEST METHODS
Single Sideband Noise Figure (SSB NF)
Noise figure (NF) is defined as the degradation in SNR per-
formance (in dB) of an IF input signal after it passes through a
component or system. It can be expressed with the equation
(
SNR
Figure
Noise
log
10
×
=
Rev. 0 | Page 9 of 44
)
OUT
IN
SNR
/
The term SSB is applicable for heterodyne systems containing a
mixer. It indicates that the desired signal spectrum resides on
only one side of the LO frequency (i.e., single sideband); thus a
“noiseless” mixer has a noise figure of 3 dB.
The
SSB noise figure
of the AD9864 is determined by the equation
(
)
[
]
SNR
)
BW
P
NF
SSB
IN
–
dBm/Hz
174
(
–
log
10
–
×
=
where
P
IN
is the input power of an unmodulated carrier,
BW
is
the noise measurement bandwidth, –174
dBm/Hz
is the ther-
mal noise floor at 293K, and
SNR
is the measured signal-to-
noise ratio in dB of the AD9864.
Note that
P
IN
is set to –85 dBm to minimize any degradation in
measured SNR due to phase noise from the RF and LO signal
generators. The IF frequency, CLK frequency, and decimation
factors are selected to minimize any spurious components
falling within the measurement bandwidth. Note also that a
bandwidth of 10 kHz is used for the data sheet specification. All
references to noise figures within this data sheet imply single
sideband noise figure.
Input Third Order Intercept (IIP3)
IIP3 is a figure of merit used to determine a component’s or
system’s susceptibility to intermodulation distortion (IMD)
from its third order nonlinearities. Two unmodulated carriers
at a specified frequency relationship (
f
1 and
f
2) are injected into
a nonlinear system exhibiting third order nonlinearities pro-
ducing IMD components at 2
f
1 –
f
2 and 2
f
2
– f
1. IIP3 graphi-
cally represents the extrapolated intersection of the carrier’s
input power with the third order IMD component when plot-
ted in dB. The difference in power (
D
in dBc) between the two
carriers and the resulting third order IMD components can be
determined from the equation
(
)
IN
P
IIP
D
–
3
2
×
=
Dynamic Range (DR)
Dynamic range is the measure of a small target input signal
(
P
TARGET
) in the presence of a large unwanted interferer signal
(
P
INTER
). Typically, the large signal will cause some unwanted
characteristic of the component or system to degrade, thus mak-
ing it unable to detect the smaller target signal correctly. In the
case of the AD9864, it is often a degradation in noise figure at
increased VGA attenuation settings that limits its dynamic range.
The test method for the AD9864 is as follows. The small target
signal (an unmodulated carrier) is input at the center of the IF
frequency, and its power level (
P
TARGET
) is adjusted to achieve an
SNR
TARGET
of 6 dB. The power of the signal is then increased by
3 dB prior to injecting the interferer signal. The offset frequency
of the interferer signal is selected so that aliases produced by the
decimation filter’s response as well as phase noise from the LO
(due to reciprocal mixing) do not fall back within the measure-
ment bandwidth. For this reason, an offset of 110 kHz was
selected. The interferer signal (also an unmodulated carrier) is
then injected into the input and its power level is increased to the
point (
P
INTER
) where the target signal SNR is reduced to 6 dB. The
dynamic range is determined with the equation
TARGET
TARGET
P
INTER
P
SNR
DR
+
=
–
Note that the AD9864’s AGC is enabled for this test.
IF Input Clip Point
The IF input clip point is defined as the input power that
results in a digital output level 2 dB below full-scale. Unlike
other linear components that typically exhibit a soft compres-
sion (characterized by its 1 dB compression point), an ADC
exhibits a hard compression once its input signal exceeds its
rated maximum input signal range. In the case of the AD9864,
which contains a Σ- ADC, hard compression should be
avoided because it causes severe SNR degradation.
相關PDF資料 |
PDF描述 |
|---|---|
| AD9864-EB | IF Digitizing Subsystem |
| AD9864BCPZ | IF Digitizing Subsystem |
| AD9864BCPZRL | IF Digitizing Subsystem |
| AD9866BCPRL | Broadband Modem Mixed Signal Front End |
| AD9866CHIPS | Broadband Modem Mixed Signal Front End |
相關代理商/技術參數 |
參數描述 |
|---|---|
| AD9864BCP | 制造商:Analog Devices 功能描述:IF SUBSYS 48LFCSP EP - Bulk |
| AD9864BCPZ | 功能描述:IC IF SUBSYSTEM GEN-PURP 48LFCSP RoHS:是 類別:RF/IF 和 RFID >> RF 前端 (LNA + PA) 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:250 系列:- RF 型:GPS 頻率:1575.42MHz 特點:- 封裝/外殼:48-TQFP 裸露焊盤 供應商設備封裝:48-TQFP 裸露焊盤（7x7） 包裝:托盤 |
| AD9864BCPZ | 制造商:Analog Devices 功能描述:IC, IF SUBSYSTEM, 16-24BIT, 6.8KHZ-270KH |
| AD9864BCPZRL | 功能描述:IC IF SUBSYSTEM GEN-PURP 48LFCSP RoHS:是 類別:RF/IF 和 RFID >> RF 前端 (LNA + PA) 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:250 系列:- RF 型:GPS 頻率:1575.42MHz 特點:- 封裝/外殼:48-TQFP 裸露焊盤 供應商設備封裝:48-TQFP 裸露焊盤（7x7） 包裝:托盤 |
| AD9864-EB | 制造商:Analog Devices 功能描述: |
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