Rohde & Schwarz ZPV - Automatic Measurement

If
the
Z AUTO
or
Y AUTO mode is selected, the ZFV
calculates
the
resonant
impedance
or admittance
in accordance with
the above
formula and
reads
it
out
on
the left-hand display.
2.5.3 Automatic Measurement
Program-controlled
measurement
is based on the same principle
as manual
measurement.
The
controller
sets the
required
button
combinations
via the
IEC
bus,
stores the
measured
data
and
calculates from
them
the equivalent
circuit
parameters.
In
automatic
operation, a phase
offset can be entered into the ZPV,
say,
for
example,
+45
,
which causes the control loop
to
pull the signal
genera-
tor to
the frequency
at
which
the
phase
of the
crystal is not
0°
but,
for
example,
+45°.
With the given
resonant impedance
Z^, the controller,
can
calculate
the dynamic
inductance
,
the
capacitance and the
Q,
from the
two
45°
frequencies
in
accordance
with the following formulae:
(Z
+25
ft)
•
tan
tf
2
IT (f -f
,T
4
if
-<f
1
P P
4
T)
°
fr
•
L
2
ff
•
fr
•
0^
Z
r
resonant
frequency
frequency
with
positive
phase offset
frequency
with
negative phase offset
phase
offset
(e.g.
45°)
resonant
impedance.
The IEG-bus
instruction
for
programming
a phase offset reads
PRINT
(a)
26: "PO
",
L
Q
where
f
f
+
f
f
=
R
38535
-
29