Atec Agilent-8568b, Agilent-8566b User Manual
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 resolution 1 Hz
SA frequency accuracy ±(tuned frequency x freq. reference error) Hz for SA zero span
SA frequency reference error Settability2 < 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
< -132 dBm (-25 dBµV) for input 9 kHz – 1 MHz
< -150 dBm (-43 dBµV) for input 1 – 1500 MHz
< -147 dBm (-40 dBµV) for input ≤ 2.0 GHz
< 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
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