6
Voltage Sensors ¸URV5-Z
The built-in detectors offer a dynamic
range of more than 90 dB for spectrally
pure sinusoidal signals with an unmodu-
lated envelope (CW, FM,
Μ
M, GMSK,
FSK, etc). This yields a voltage measure-
ment range of 200
Π
V to 10 V (
#
60 dBm
to +33 dBm into 50
:
) for the
¸URV5-Z2, and of 2 mV to 100 V
(
#
40 dBm to +53 dBm into 50
:
) for the
¸URV5-Z4. With modulated envelope
or high harmonic content, the insertion
units should be operated only within the
square-law region of the detectors, which
for the ¸URV5-Z2 ends at approx.
22 mV (
#
20 dBm into 50
:
) and for the
¸URV5-Z4 at 220 mV (0 dBm into
50
:
). In this region, the behavior of the
insertion units is similar to that of a ther-
mal power meter, i.e. the rms voltage or
the equivalent average power is mea-
sured.
Owing to the high decoupling of the
detector from the RF connectors, inser-
tion loss of the ¸URV5-Z4 is very low,
i.e. not exceeding that of a line of equiva-
lent length. The ¸URV5-Z4 is there-
fore truly transparent and can be inserted
into any test circuit without influencing
the parameters to be measured.
Both insertion units are equipped with a
calibration data memory that contains
information about the individual sensor
characteristics such as frequency
response, linearity, temperature coeffi-
cient, etc. The stored data is automati-
cally considered by the base unit during
operation so that the user can plug the
sensor in and immediately start measur-
ing.
Insertion Units ¸URV5-Z2
and ¸URV5-Z4
The Insertion Units ¸URV5-Z2 and
¸URV5-Z4 are used for uninterrupted
level measurements between source and
load and for terminated power measure-
ments. Due to their wide frequency range
they are ideal especially for the measure-
ment of EMC test levels as well as many
general-purpose applications.
Compared to the terminating power sen-
sors of the ¸NRV family, the
¸URV5-Z2 and ¸URV5-Z4 inser-
tion units offer a larger dynamic range, a
much lower frequency limit (9 kHz with
the ¸URV5-Z2) and the possibility of
using them during operation of the load.
Both units are made up of a short, coaxial
line between the two RF connectors, in
the middle of which the voltage is
tapped: directly with the ¸URV5-Z2,
and via a capacitive 20 dB divider with
the ¸URV5-Z4. If the insertion units
are match-terminated, the voltage is con-
stant over the whole length of the line, so
a fixed relationship is obtained between
applied RF power and test voltage:
P =V
rms
2
/ 50
:
. In this configuration, the
insertion units provide precise absolute
power and level measurements.
The insertion units are calibrated so that
the power incident upon them is indi-
cated. With a poorly matched load, pre-
cise absolute-value measurements are
not possible, but relative measurements
can be performed and system applica-
tions implemented in which subsequent
calibration of the complete test setup
takes place. Switchover between voltage,
level and power indication is made at the
base unit.
The Insertion Unit ¸URV5-Z2, 200
Π
V to
'
10 V, 9 kHz to
'
3 GHz
The Insertion Unit ¸URV5-Z4, 2
'
mV to 100 V, 100 kHz to 3 GHz
