Tektronix 2221 User Manual

Basic
Applications
-
2221
Operators
7. Adjust the TRIGGER LEVEL control for a stable
display .
More
accurate
phase
measurements can be
made
by
using the X10
Magnifier to
increase the
sweep
speed
without
changing the
SEC
/ DIV
Variable
control
setting .
П
П
П
П
П
Л
8. Set
the
SEC
/
DIV switch to
a
sweep
speed
which
displays about one full cycle of the waveforms .
9.
Position the
displays and
adjust the SEC
/ DIV
Vari
able
control so
that
one
reference
-
signal
cycle
occupies
exactly eight horizontal graticule divisions at the 50 % rise
time
points
( see
Figure 6-9 ) .
Each division of
the
graticule
now
represents
45 °
of the
cycle ( 360 °
8
divisions ) , and
the
horizontal
graticule
calibration can
be
stated as 45 °
per
division ,
EXAMPLE : If the
sweep
speed were
increased 10
times
with
the
magnifier
(
X10
Magnifier
out
) ,
the
magnified
horizontal
graticule
calibration
would be 45 °
/
division
divided by 10 (
or 4.5 ° /
division
) .
Figure
6-10
shows
the
same
signals
illustrated in
Figure 6-9 ,
but
magnifying
the
displays
results
in a
horizontal
difference of
6
divisions
between
the
two
signals .
Substituting the given values in the phase difference
formula :
Phase
Difference
6 div x
4.5 °
/ div =
27 °
10. Measure
the
horizontal
difference
between
corresponding points on
the
waveforms at a
common
hor
izontal
graticule
line ( 50 %
of rise time
) and
calculate the
phase
difference
using the
following
formula
:
Phase
Difference
Horizontal
Difference x
(
Divisions )
Horizontal
Graticule
Calibration (
deg
/
div
)
TIME
COMPARISON
П
Л
EXAMPLE : The
horizontal
difference is
0.6
division with
a
graticule
calibration of 45 ° per
division
as
shown
in
Figure
6-9
.
In a
similar
manner to
"
Amplitude
Comparison
, "
repeated time
comparisons
between
unknown
signals
and
a
reference signal (
e.g.
,
on
assembly -
line
test
)
may be
easily and
accurately
measured
with the
instrument
.
To
accomplish this , a reference signal of known time duration
is
first set to
an
exact
number of
horizontal
divisions by
adjusting the SEC / DIV switch and the SEC / DIV Variable
control .
Unknown
signals
can
then be
compared
with the
reference
signal
without
disturbing
the
setting of
the
SEC
/
DIV
Variable
control .
The procedure is
as
follows
:
Substituting the given values into the phase difference
formula :
Phase
Difference
0.6 div
x 45
° / div
= 27 °
П
1
CHANNEL 1
( REFERENCE )
CHANNEL
2
( LAGGING )
CHANNEL 1
(
REFERENCE )
CHANNEL 2
100
100
1
90
90
B
MEASURE
TIME
FROM
ATO ( B
B
MEASURE
TIME
FROM
A
А
ATOⓇ
JO
03 .
a
HORIZONTAL
DIFFERENCE
17
1 V
10us
д
П
п
П
П
П
OL
Ime
8 DIVISIONS
( 360 ° )
HORIZONTAL
DIFFERENCE
4998-37
4998-43
Figuro
6-9
.
Phase
difference
.
Figure
6-10
.
High
-
resolution
phase
difference .
6-11

Tektronix 2221 Specifications

General

Brand	Tektronix
Model	2221
Category	Test Equipment
Language	English