Your High-Performance
Spectrum Analyzer can also
be a Test Receiver
Add the 85685A RF preselector to the
8566B or 8568B general-purpose spectrum analyzer, and you have a test receiver for specialized applications. The RF
preselector enhances these high-performance spectrum analyzers with tracking
filters and preamplifiers that cover the
20 Hz to 2 GHz range. The spectrum
analyzer/test receiver is sensitive to
low-level signals while providing overload protection from out-of-band signals.
The result, for tests in the presence of
high-level interference, is a measurement range 30 dB greater than that of the
spectrum analyzer alone. (The improvement is even greater in the presence of
broadband pulse-interference.)
Agilent
RF Preselector, 20 Hz to 2 GHz
For the 8566B or 8568B Spectrum Analyzer
Data Sheet
The test receiver is easy to operate; simply use the spectrum analyzer controls
without concern for preselector settings.
The preselector automatically adjusts
input-filter tracking, and the spectrum
analyzer reports preselector operating
conditions on the CRT display. For remote
operation with a computer, the receiver
system is fully GPIB programmable (GPIB
is hardware, software, documentation,
and support for IEEE-488 and IEC-625,
worldwide standards for interfacing
instruments.)
The 85685A preselector adds:
Automatic filter tracking
•
Input overload protection
•
Low system noise
•
to the 8566B and 8568B spectrum analyzers.
EMI Testing According
to CSPR Publication 16
Recommendations
Combining the 85685A RF preselector
with the 8566B or 8568B spectrum analyzer and the 85650A quasi-peak adapter
produces an EMI receiver with the characteristics recommended in CISPR publication 16
the measurement sensitivity and overload protection needed for FCC and VDE
radiated emission testing at open sites.
For commercial and MIL-STD conducted
EMI tests, the low-frequency input tolerates large impulses and line impedance
stabilization network (LISN) transients. A
built-in calibrator ensures ±2.0 dB absolute-amplitude accuracy as required by
the FCC and VDE. For measurement confidence, a linearity check tests for system
overload and distortion.
The sample display shows results for
VDE 0871 emission testing at an open
site. To prevent overload from the highlevel ambient signals, a spectrum analyzer needs input attenuation. This however,
increases displayed noise, which can
mask the low-level emissions. Using the
RF preselector in this test eliminates the
need for adding attenuation. The noise
of the spectrum analyzer, as shown,
exceeds the VDE limit, but the spectrum
analyzer/test receiver noise is more than
10 dB below the lowest limit.
1. Comite International Special Des Perturbations
Radio-Electriques (CISPR) publication 16 is the
"CISPR specification for radio interference measuring apparatus and measurement methods."
1
. The RF preselector provides
Signal Monitoring in the
Presence of High-Level
Interference
The RF preselector gives the 8566B
or the 8568B spectrum analyzer the
sensitivity and selectivity of a receiver.
The spectrum analyzer/test receiver
measures signals within the preselector filter passband and rejects outof-band interference by 40 dB. Even
in the presence of interference with
a total input power of +10 dBm, your
test receiver can monitor signals down
to -150 dBm.
The RF preselector improves signal
reception for the broadband signal
environment of a mobile test station.
In the 150 – 170 MHz business band,
the RF preselector reduces interference from radio and TV broadcast
stations and from amateur radios. For
the 800 – 900 MHz cellular radio band,
the spectrum analyzer/test receiver
makes field strength measurements
on cellular base-station transmitters
while rejecting interference from cellular mobile transmitters.
Transmitter Spurious
Testing with Fast Wideband
Measurements
Reduce transmitter-spurious test time
by adding the RF preselector to your
8566B or 8568B spectrum analyzer. The
preselector decreases input overload
from the out-of-band carrier and thereby
increases the range for measuring lowlevel signals. Compared to the spectrum
analyzer alone, the spectrum analyzer/
test receiver uses a wider resolution
bandwidth for the same measurement
range, resulting in a faster sweep time.
For example, to measure spurious signals over a 1 GHz frequency range at
–100 dB relative to the transmitter carrier, a spectrum analyzer by itself takes
3000 seconds, but when configured as a
test receiver it requires only 3 seconds.
2
Specifications
Specifications describe the instrument's warranted performance over the temperature range of 0°C to +55°C unless otherwise
noted. Typical values for the specified parameters represent probable but non-warranted performance. Nominal values provide
useful but non-warranted information about functional performance.
Test Receiver
The following system specifications apply when the 85685A RF preselector (RFP) operates with the 8566B or 8568B spectrum
analyzer (SA) and with or without the 85650A quasi-peak adapter (QPA). The test receiver system is fully GPIB programmable.
Refer to the specific instrument data sheets for more detailed information.
Test receiver frequency
Parameter Specification
Frequency range
RFP bypass
SA frequency resolution1 Hz
SA frequency accuracy±(tuned frequency x freq. reference error) Hz for SA zero span
SA frequency reference errorSettability2 < 10-8, Drift < 2 x 10-7/year
SA Frequency selectivity
3 dB resolution BW
1
3
20 Hz – 1.5 GHz with 8568B
20 Hz – 2.0 GHz with 8566B
20 Hz – 18 GHz (nominal) with 8568B
10 Hz – 3 MHz in 1, 3, 10 sequence
Test receiver amplitude
Parameter Specification
Measurement range-150 to +30 dBm (-43 to +137 dBµV) (nominal)
Gain compression (0 dB atten. for RFP and SA
Inside RFP passband
Outside RFP passband
Displayed average noise level
(0 dB atten. for RFP and SA 10 Hz resolution BW)
Broadband signal sensitivity
(0 dB atten. for RFP and SA, 10 Hz resolution BW)
Second harmonic distortion (0 dB atten. for RFP and SA)
For -35 dBm input signal:
Within RFP passband
Outside RFP passband
Third order intermodulation (0 dB atten. for RFP and SA)
For two -35 dBm input signals:
Within RFP passband
Outside RFP passband
Residual responses
(RFP input terminated, 0 dB atten. for RFP and SA
Amplitude accuracy6
(+10° to + 30°C, 10 dB SA atten. 0 –20 dB RFP atten.)
5,6
< 1 dB (nominal) for input ≤ -30 dBm
< 1 dB (nominal) for input ≤ +10 dBm
< 31 dBµV/MHz (nominal) for input < 1 MHz4
< 13 dBµV/MHz (nominal) for input = 1 – 1500 MHz
< 16 dBµV/MHz (nominal) for input ≤ 2.0 GHz
< -55 dBc (nominal), Equiv. SOI = +20 dBm
< -75 dBc (nominal), Equiv. SOI = +40 dBm
< -40 dBc (nominal), Equiv. SOI = -15 dBm
< -110 dBc (nominal), Equiv. SOI = +20 dBm
< -90 dB for input 2 kHz – 1 MHz
< -112 dB for input ≥1 MHz
< -120 dB (typical) for input ≥1 MHz
±2.0 dB for input < 1.0 GHz
±3.0 dB for input ≥1.0 GHz
4
RFP bypass
SA specification plus:
± 0.5 dB (nominal) for input ≤ 2.0 GHz
± 1.0 dB (nominal) for input > 2.0 GHz
3
CISPR EMI Receiver
The following system specifications apply when the 85685A RF preselector (RFP) operates with the 8566B or 8568B spectrum
analyzer (SA) and with the 85650A quasi-peak adapter (QPA). The EMI receiver system has the characteristics recommended in
CISPR publication 16 and is fully GPIB programmable. Refer to the specific instrument data sheets for more information.
CISPR EMI receiver frequency
Parameter Specification
Frequency range10 kHz – 1 GHz
SA frequency resolution1 Hz
SA frequency accuracy±(tuned frequency x freq. reference error) Hz
SA frequency reference errorSettability2 < 10-8, Drift < 2 x 10-7/year
SA Frequency selectivity
CISPR 6 dB bandwidth (QPA)
9
200 Hz for input = 10 – 150 kHz (band A)
9 kHz for input = 150 kHz – 30 MHz (band B)
120 kHz for input = 300 – 1000 MHz (band C, D)
Make dedicated receiver measurements
with a general-purpose spectrum analyzer
4
CISPR EMI Amplitude
ParameterSpecification
Measurement range+137 dBµV to noise floor (refer to amplitude sensitivity table)
Amplitude accuracy
(+10° to +30°C, 0 – 20 dB RFP atten.)
Calibration
Linearity check3 dB input attenuator test for system overload and distortion
Impulsive signal toleranceInput #1 withstands LISN transients (RFP)
Detection
Audio outputSpeaker with volume control (QPA)
10
9
8
±2.0 dB for 10 dB SA atten.
± 2.5 dB for 0 dB SA atten.
Automatic calibration for absolute amplitude with comb
generator (RFP)
(RFP)
Input #2 withstands CISPR calib. pulses (RFP)
Peak and average (SA), quasi-peak (QPA)
CISPR EMI Amplitude sensitivity
EMI receiverSpecification
Frequency bandResolution bandwidth (6 dB)Average noise6
(RFP/SA atten. = 0 dB)
10 – 150 kHz (band A)200 Hz-12 dBµV4
-17 dBµV typical
150 kHz – 1 MHz (band B)9 kHz+4 dBµV
-1 dBµV typical
1 – 30 MHz (band B)9 kHz-13 dBµV
-16 dBµV typical
30 – 1000 MHz (band C, D)120 kHz-1 dBµV
-6 dBµV typical
Quasi-peak noise
(RFP/SA atten. = 0 dB)
-15 dBµV (nominal)
0 dBµV (nominal)
-11 dBµV (nominal)
0 dBµV (nominal)
5
85685A RF Preselector
The following instrument specifications apply to the 85685A RF preselector (RFP).
85685A RF preselector input
ParameterSpecification
Input #1Input #2
Frequency range
RFP bypass
Connector type
Fuse blow time
Maximum safe input power
Average power
Impulsive signals
≥ 10 dB RFP atten.
≥ 20 dB RFP atten.
DC voltage0 Volts
Standing wave ratio (SWR)12
10 dB RFP atten.
0 dB RFP atten.
RFP bypass
Preamplifier gain20 dB (nominal) for 0 dB RFP atten.
1
20 Hz – 50 MHz20 MHz – 2 GHz
BNC, 50 Ω (nominal)
< 0.1 sec for > + 35 dBm
+30 dBm (1 Watt)
100 Watts peak for a 10 µs pulse
2,000 Watts peak for a 10 µs pulse11 (nom.)
< 1.5:1
< 1.5:1 (nominal)
NA
0 – 50 dB in 10 dB steps (nominal)
Add 3 dB (nominal)
BW range = 10 kHz• 1 MHz (nom.) for input < 2 MHz
10% (nom.) of tuned freq. for input = 2 – 55 MHz
5% (nom.) of tuned freq. for input = 55 – 500 MHz
20 MHz (nom.) for input = 500 – 2000 MHz
> 40 dB (nominal)
DC – 18 GHz (nom.)
Type N, 50 Ω (nom.)
NA
+30 dBm (1 Watt)
NA
< 1.5:1
< 2.0:1 (nominal)
< 1.5:1 (nominal)
ParameterSpecification
Comb generator
Line spacing
Line amplitude
SWR
GPIB interface*
Private BUS
Public BUS interface functions (public BUS)
85685A RF preselector output
100 kHz, 500 kHz, 1 MHz, 5 MHz (nominal)
-40 to -60 dBm (nominal)
< 1.5:1 (nominal)
Digital BUS and sweep control between RFP and SA
IEEE 488-1978 BUS
SH1, AH1, T6, L4, SR1, RL1, PPO, DC1, DT1, C0, E1
6
General
ParameterSpecification
Temperature0° to + 55°C operating
-40° to +75°C storage
Warm-up time30 minutes after cold start
Temp. equilibrium2 hours after warm-up
EMIConducted and radiated interference is in compliance with MIL-STD 461A methods in CE03 and
RE02, CISPR publication 11 (1975), and Messempfaenger-Postverfuegung 526/527/79
(Kennzeichnung Mit F-Nummer/Funkschutzzeichen).
Power requirements100, 120, 220, or 240 V RMS +5%, -10%; 50 –400 Hz; 35 VA (nominal)
Weight19 kg (42 lbs) net (nominal)
Size133 mm (5.25") H x 425 mm (16.75") W x 508 mm (20.0") D (nominal)
Firmware compatibility
for RFP operation with:
8566B, firmware data ≥ 5.5.85
8566B, firmware data < 5.5.85
8566A, any firmware date
8568B, firmware data ≥ 14.1.85
8568B, firmware data < 14.1.85
8568A, any firmware date
85864B EMI measurement software
Transit case, part number 1540-0663
EMI accessories13: Antennas, LISNs, current probes, and amplifiers
7
Agilent Email Updates
Agilent Direc
t
Agilent Open
Footnotes:
1. The RFP bypass switch connects input
#2 directly to the RF output.
2. Refer to spectrum analyzer test and
adjustment manual for the correct
frequency reference adjustment.
3. Refer to spectrum analyzer data sheet
for filter BW accuracy and filter shape.
4. 17 dB higher with 8566B for frequency
< 50 kHz.
5. Sensitivity is approximately equal to
system peak noise level.
6. Peak noise is nominally 8 dB higher
than average noise.
7. Measurement sensitivity is normalized
to 1 MHz resolution BW.
8. Specifications apply after system
calibration with the comb generator
in the 85685A. Refer to 85685A operating manual for correct amplitude measurement technique.
9. The system meets CISPR publication
16 recommendations for resolution
BW, detector time constant, and
detector pulse response.
10. System calibration can be verified with
an external CISPR standard pulse calibration generator.
11. Typical LISN transients.
12. SWR is measured at the tuned
frequency of the spectrum analyzer.
13. Refer to the EMI measurement
solutions guide (5954-2702) for more
information.
www.agilent.com/find/emailupdates
Get the latest information on the products and
applications you select.
www.agilent.com/find/open
Agilent Open simplifies the process of connecting and programming test systems to help
engineers design, validate and manufacture
electronic products. Agilent offers open connectivity for a broad range of system-ready instruments, open industry software, PC-standard I/O
and global support, which are combined to more
easily integrate test system development.
www.agilent.com/find/agilentdirect
Quickly choose and use your test equipment
solutions with confidence.
www.agilent.com
Agilent Technologies’ Test and Measurement Support,
Services, and Assistance
Agilent Technologies aims to maximize the value you
receive, while minimizing your risk and problems. We
strive to ensure that you get the test and measurement
capabilities you paid for and obtain the support you need.
Our extensive support resources and services can help
you choose the right Agilent products for your applications
and apply them successfully. Every instrument and system
we sell has a global warranty. Two concepts underlie
Agilent’s overall support policy: “Our Promise” and “Your
Advantage.”
Our Promise
Our Promise means your Agilent test and measurement
equipment will m eet its adve rt is ed per formance a nd
functionality. When you are choosing new equipment, we
will help you with product information, including realistic
performance specifications and practical recommendations
from experienced test engineers. When you receive your
new Agilent equipment, we can help verify that it works
properly and help with initial product operation.
Your Advantage
Your Advantage means that Agilent offers a wide range of
additional expert test and measurement services, which
you can purchase according to your unique technical and
business needs. Solve problems efficiently and gain a
competitive edge by contracting with us for calibration,
extra-cost upgrades, out-of-warranty repairs, and onsite
education and training, as well as design, system integration, project management, and other professional engineering services. Experienced Agilent engineers and technicians worldwide can help you maximize your productivity,
optimize the return on investment of your Agilent instruments and systems, and obtain dependable measurement
accuracy for the life of those products.
Agilent T&M Software and Connectivity
Agilent’s Test and Measurement software and connectivity
products, solutions and developer network allows you to
take time out of connecting your instruments to your computer with tools based on PC standards, so you can focus
on your tasks, not on your connections. Visit
www.agilent.com/find/connectivity
for more information.
For more information on Agilent Technologies’ products, applications or services, please contact your local
Agilent office.