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參數(shù)資料
| 型號： | HFA3600 |
| 廠商： | Intersil Corporation |
| 英文描述： | Low-Noise Amplifier/Mixer |
| 中文描述： | 低噪聲放大器/混頻器 |
| 文件頁數(shù)： | 15/16頁 |
| 文件大?。?/td> | 430K |
| 代理商： | HFA3600 |
15
HFA3600 Mixer Evaluation Notes
The evaluation of the HFA3600 mixer by itself is facilitated by
the demo-board design which provides access to the 3 ports
by SMA connectors. As discussed before, RF to IF
feedthrough and LO to RF/IF ports moderate isolation can
cause errors during noise measurements.
The inherent RF to IF feedthrough of the single balanced
mixer mandates that noise measurements be single side
band only (with an appropriate band pass filter at the RF
frequency of interest). Because of this lack of isolation, the
incoming energy located at the IF passband from a
broadband noise source for example, will feedthrough and
cause significant noise figure measurement errors.
As noise measurement equipment often makes use of
broadband noise sources with energy covering a wide
spectrum, SSB measurements are made using a band
pass filter in front of the RF port. The role of the band pass
filter is to prevent the image and IF noise energy from being
fed to the mixer.
However, band pass filters exhibit poor return losses at
frequencies outside their passbands. Because a moderate
amount of power from a local oscillator is transferred back to
the RF port in many active mixers, and this returned LO
signal is outside the passband of the SSB filter being used,
the signal will get reflected back again to the RF port due to
impedance mismatch between the filter and the RF port.
This impedance mismatch occurs at the LO frequency and
these multiple signal reflections can affect gain and noise
performance of the mixer. This situation, although not a
problem for the actual receiver design, can become a source
of error during mixer noise measurements.
To minimize the problem, the simplest method is to provide a
short connection (well below
λ
/4 of the LO frequency)
between the filter and the RF port. In case a coaxial cable
connection is required, it maybe necessary to provide a
length of cable which assures minimum degradation to the
noise figure reading. Long cables above 3 feet can provide
the required standing wave dissipation for measurements in
the 800MHz to 1GHz range. Note that long cable losses
must be taken into account for the purpose of noise figure
measurements. Adjustable line stretchers or isolators at the
RF input port could also be used to optimize noise figure
readings as an option for the mixer evaluation.
And finally, the recommendation of filtering the local
oscillator signal before applying it to the LO port is important
for accuracy of noise measurements when evaluating the
mixer by itself, due to the typical LO to IF feedthrough in
single balanced mixers.
HFA3600 LNA Evaluation Notes
The evaluation of the LNA is straightforward. SMA
connectors are provided in the demo-board. There are no
recommendations for evaluating the LNA block other than
using typical RF amplifier test techniques.
Final Note
The cascaded evaluation of the HFA3600 LNA and mixer
blocks including an image rejection or high pass filter is the
best method to obtain accurate results. The gain and noise
performance contribution of the LNA and filter to the
cascaded results surpass considerably the performance
contribution of the mixer. The data collected by cascading
the blocks together reflects the performance at the system
level which includes the filter of choice for a required design.
FIGURE 37A. SSB NOISE FIGURE MEASUREMENT
FIGURE 37B. DSB NOISE FIGURE MEASUREMENT
TABLE 3. DSB MEASUREMENT SET UP
(NO INPUT BANDPASS FILTER)
IMAGE FILTER
NF
(dB)
GAIN
(dB)
COMMENTS
Saw, 3dB Loss
5.1
16.0
Equivalent to SSB
Measurement
Short/No Filter
1.8
31
Invalid Measurement
Π
Filter, No Loss
at the RF
Frequency
3.6
19.0
Note 3
NOTES:
2. Thesinglesidebandinputfilter(filterA)lossisaccountedforand
removed in the Noise figure and gain values.
3. The difference of a DSB to a SSB noise figure is theoretically
3dB. The expected value of 2.2dB NF for a DSB measurement
is degraded to 3.6db due to a small attenuation of the
Π
filter at
the image frequency.
4. The cascaded results presented in the AC Specifications Table
of the data sheet are calculated assuming the use of an ideal
image filter (no loss) and a SSB measurement.
HFA3600
LO
NOISE
SOURCE
HP8970A
NOISE
FIGURE
METER
BROADBAND
TUNED
AT THE
RF FREQ
FILTER A
LNA
FILTER
HP346B
LOW NOISE
HFA3600
NOISE
SOURCE
LNA
BROADBAND
HP346B
LO
LOW NOISE
FILTER
HP8970A
NOISE
FIGURE
METER
HFA3600
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| HFA3600IB | Low-Noise Amplifier/Mixer |
| HFA3600IB96 | Low-Noise Amplifier/Mixer |
| HFA3624 | 2.4GHz Up/Down Converter |
| HFA3624IA | 2.4GHz Up/Down Converter |
| HFA3624IA96 | 2.4GHz Up/Down Converter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| HFA3600 WAF | 制造商:Harris Corporation 功能描述: 制造商:Intersil Corporation 功能描述: |
| HFA3600_02 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Low-Noise Amplifier/Mixer |
| HFA3600IB | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| HFA3600IB96 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Low-Noise Amplifier/Mixer |
| HFA3624 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:2.4GHz Up/Down Converter |
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