Rohde & Schwarz URV5-Z4 - Page 37

After
the
zero
adjustment
the
frequency
is
set
to
100
kHz
and
the
output
voltage
measured
at
the
following
values:
0.2
mV;
3
mv;
10
mV;
30
mV;
100.mV:
0.3
V:
1
V:
3
V;
10
V
The
permissible
tolerances
are
specified
in
the
performance
test
report.
Please
carry
out
the
measurements
in
the
stated
se-
quence.
After
measurement
of
high
voltages
the
insertion
unit
re-
quires
a
certain
recovery
time
before
low
levels
can
be
measured
again.
3.3.2.2
Checking
the
Reflection
Coefficient
Linearity
and
reflection
coefficient
are
characteristic
data
of
the
10-V
insertion
unit.
If
both
are
within
the
specifications,
the
frequency
response
will
also
be
within
the
specified
toleran-
ces.
For
measuring
the
reflection
coefficient
any
test
set
up
to
2
GHz
and
a
directivity
of
at
least
46
dB
will
be
suitable.
The
measu-
rement
level
is
uncritical,
since
it
has
only
little
influence
on
the
reflection
coefficient.
The
10-V
insertion
unit
to
be
tested
is
terminated
at
one
end
by
50
n
for
low
reflection;
for
the
measurement
result
it
is
irrelevant
whether
the
insertion
unit
is
connected
to
the
basic
unit
or
not.
Care
should
be
taken
that
the
gegiection
coefficient
of
the
50-h
termination
does
not
exceed
The
permissible
reflection
coefficient
tolerances
for
the
10-V
insertion
unit
are
specified
for
100
MHz
to
2
GB:
in
the
per-
formance
test
report.
These
tolerances
do
however
not
include
the
measurement
error
of
the test set used. Please check first what reflection coeffi-
cients you can still measure with sufficient accuracy. The fol-
lowing example should be helpful. A test set with a directivity
of
46
dB
already
yields
an
uncertainty
of
20.5%.
Together
with
the
reflection
coefficient
of
the
termination
of
0.5%,
the
entire
test
set
has
a
measurement
error
of
21%.
Therefore,
only
re-
flection coefficients > 3% can reliably be determined. Con-
sequently,
the
reflection
coefficient
of
the
10-V
insertion
unit
can
only
be
checked
for
frequencies
above
500
MHz.
A
test
set
for
measuring
the
reflection
coefficient
up
to
2
GHz
and
with
a
directivity
of
46
dB
is
described
in
section
3.8.
It
contains
the
R&S
VSWR
Bridge
ZRBZ
and
a
URVS
with
two
RF
probes.
394.8010.02
3-17
E‘Z
0.2 my; 3 my; 10 my; 30 my; 100
.mV: 0.3 V; 1 V: 3
V:
10 V
After the zero adjustment the
frequency is Set to
100
kHz and the
Output voltage measured at the
following Values:
The perıuissible tolerances are specified in the performance
test
report. Please carry out the measurements in the stated se-
quence. After measurement of high voltages the Insertion Unit re-
quires a certain recovery time before low levels can be measured
again.
3.3.2.2
Checkínq the Reflection Coefficient
Linearity and
reflection coefficient are characteristic data of
the 10-V
Insertion Unit. If both are within the specifications,
the frequency response will also be weithin the specified toleran-
ces.
For measuring the reflection coefficient any test Set up to 2 GHz
and a directivity of at least 46 dB will be suitable. The measu-
rement level is uncritical, since it has only little influence on
the reflection coefficient. The 10-V Insertion Unit to be tested
is terminated at one end by 50 so for low reflection; for the
measurement result it is irrelevant whether the Insertion Unit is
connected to the basic Unit er not. Care should be taken that the
reflection coefficient of the 50-sı termination does not exceed
0.5%.
The permissible reflection co.efficient tolerances for the 10-v
inser tion Unit are specified for 100 MHz to 2 GHz in the per-
formance test Report.
These tolerances do however not include the measurement error of
the test Set used. Please Check first what reflection coeffi-
cients you can still measure Voith sufficient accuracy. The fol-
lowing example should be helpful. A test Set Voith a directivíty
of 46 dB already yields an uncer tainty of ±O.5%. Together Voith
the reflection coefficient of the termination of 0.5%, the entire
test Set has a measurement error of ±1%. Therefore, only re-
flection coefficients › 3% can reliably be determined. Con-
sequently, the reflection coefficient of the 10-V Insertion Unit
can only be checked for frequencies above 500 MHz.
A Test Set for measuring the reflection coefficient up to 2 GH:
and Voith a directivity of 46 dB is described in section 3.8. It
container the R&S VSWR Bridge ZRB2 and a URV5 Voith toto RF probes.
394.8010.02
3.17
E-2