Service manual

4
Laboratory-quality
mea sure ments in the fi eld
Obtain all of the performance of your
bench-top analyzer in a portable
instrument.
Ease-of-use
Portability, versatility, and per for-
mance are valued attributes, but to
be really valuable an instrument must
also be easy to use. The 35670A has
a friendly front panel, plus online help
that’s always available to answer
your questions. An interactive mea-
sure ment state lets you configure
the instrument setup from a single
display.
FFT-based spectrum analyzers,
such as the 35670A, are ideal for
measuring the spectra of low-fre quen-
cy signals like speech or me chan i cal
vibration. Transient com po nents,
usually missed with swept-frequency
analyzers, are easily measured and
displayed at speeds fast enough
to follow trends. The 35670A has
both the per for mance and features
required to take full ad van tage of this
tech nol o gy.
16-bits for high per for mance
With a 16-bit ADC (90 dB typical
dynamic range) and a real-time
bandwidth of 25.6 kHz, you can be
sure nothing will be missed. Resolve
signals using 100 to 1600 lines
res o lu tion, or for really close-in analy-
sis, use frequency zoom to resolve
signals with up to 61 µHz resolution.
Use time or RPM arming to develop
waterfalls of sequential vibration
spectra for trend analysis or for an
overview of device vibration.
Power and linear spectrums
Match your spectrum measurement
mode to the signal being tested.
Use linear spectrum analysis to
measure both the amplitude and
phase of periodic signals such as the
spectra of rotating machinery. Power
spectrum analysis is provided for
averaging nonrepetitive signals.
Averaging
Various averaging modes let you
further refine spectrum analysis mea-
surements. Time averaging extracts
repetitive signals out of the noise
while rms averaging reduces the
noise to its mean value. Ex po nen tial
averaging, available for both time and
rms averaging, is useful for reducing
the noise while following changing
signals—tracking the resonance
shifts in a fatiguing structure for
example.
Spectrum Analysis
Two spectrums
of road induced
vibration measured at
different speeds are
com pared using the
front/back mode of
the Agilent 35670A.