O'Reilly logo

Oscilloscopes, 5th Edition by Ian Hickman

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

3
Advanced real-time
oscilloscopes
Entirely at the other end of the price range from the basic type
of
oscilloscope described in Chapter
2
is the advanced oscilloscope.
This typically
has
a
host
of
features not found on
a
basic scope.
and
may be
a
mainframe plus plug-in system or a stand-alone scope.
The latter is often dcscrihcd
as
a ‘portablc’, to distingiiish
it
from
the former. The really advanced end
of
the real-time oscilloscopc
rnarkct
is
shared bctwccn a small numhcr
of
manufacturers,
not.
more
t
liar1
half
a
chzrri.
Ncverthelrss, however many facilities
an
oscilloscope manufacturer’s top-of-tl-ie-range produc~
may
have,
what
really
marks
out
the
men
from the
boys
is handwidth. Fcw
indrcd arc the manufacturcrs
of
real-time oscilloscopes
wit.h
a
Y
bandwidth
in
excess
of
300
MHz.
Yct
in high-speed computers
50MHz
and
100MHz
clock
rates are by no
inearis
uncommoii,
while in analogue systems a frequency response extending
up
to
the lower end
of
the
UHF
band often reveals circuit problems, such
as parasitic oscillations, that would otherwise pass unnoticed
unless a spectrum ana1yst.r were
to
hand.
As
in
Chaptcr
2,
an
oscilloscope that is representative
of
its
class
is taken
as
an example,
and
its facilities discussed in detaiI. The
oscilloscope chosen For this purpose is the Fluke
modcI
PM3094
(Figure
3.1
j.
This
is
a
stand-alone instrument, requiring
no
plug-
ins. Its facilirics are comprchensive, and the tollowing description
covers nenrlv
all
01
the
points relevant.
1.0
high-pcrfnrmancc
oscilloscopes.
AI
thc
cnd
of thc chapter, however, rcfcrcnce .is
made
to
mainfmrrit.
plus
pl~ig-irt
systerns.
These
art.
potentially
more vcrsatilr
than
stand-alonc instruments, but gcnet-ally
work
out
rriory
c.xpt.tisivc.
for
11ir
sariic‘
iwrformancc.
Stand-alonc oscilloscope
The
FM3094
i\
at the top end
of
a
rangc
of
instruments offering
l00MHz
(PM3082,
PM3084)
or
200
MHz
(PM3092,
PM3094)
bandwidth. The
Ph13084
and
PM3094
have
four
identical
fully
Advanced real-time oscilloscopes 19
Figure 3.1 The microprocessor-controlled PM3094 advanced analogue real-
time oscilloscope has a bandwidth of 200MHz and a wide range of features
covered in this chapter (reproduced by courtesy of Fluke Europe BV)
featured input channels, while the other two more economically
priced instruments provide two such channels plus two supple-
mentary channels. The latter, with just two input sensitivity
settings of 0.1 V/division and 0.5V/division (I V/division and
5 V/division when used with a xl 0 probe), are ideal for use in logic
circuit testing. All four instruments have the controls arranged in
'functional groups', in designated sub-panel areas of the front
panel. Thus all the Channel 1 controls are grouped together, as are
those for the other channels, for the Main Timebase and etc. The
rest of this chapter describes the PM3094, but most of the
following applies to all four instruments in the range.
The PM3094 will first be described in its basic form, that is
without any of the various options available. Like many modern
instruments, the PM3094 incorporates a tapless switching mode
power supply, obviating the need for a mains voltage adjustment
switch. It operates from any a.c. supply of 100 V to 240 V rms, 50
to 400 Hz.
As one would expect, the PM3094 has all the facilities found in
the Metrix OX71 described in Chapter 2, though sometimes
differently labelled. The facilities offered by the PM3094 are so
extensive that it is not possible in the confines of this chapter to
describe them all in full detail: they greatly surpass the capabil-
ities of the Tektronix 475A described in the first edition of this
book in 1981, although that early model's bandwidth was 25 per

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required