Rohde & Schwarz HM8118, User Manual

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Instrument Functions
20Hz and 200kHz. In the CORR menu, use the arrow keys
7
to select the FRQ function to choose the mea-
surement frequency, press the knob
6
(editing mode) and
select the desired measurement frequency via knob. Press
the knob again to confirm the selection.
7.2.4 FUNC Function
You can use the FUNC function to select the measurement
function for the load impedance LOADM and LOADS. You
can choose from the following functions:
Ls-Q, Lp-Q, Ls-Rs,
Lp-Rp, Cs-D, Cp-D,
Cs-Rs, Cp-Rp, Rs-Q,
Rp-Q, Z-Θ, Y-Θ,
R-X G-B
In the CORR menu, use the arrow keys
7
to se-
lect the FUNC function to choose the measurement func-
tion, press the knob
6
(editing mode) and select the desi-
red function via knob. Press the knob again to confirm the
selection.
7.2.5 Correction Factors LOADM / LOADS
You can use the LOADM function (main measurement va-
lue display) to save a reference value for the load impe-
dance LOAD in the reference memory LOADM. Depending
on the parameter FUNC H, you can choose one of the fol-
lowing as unit for the measurement value: mH, µH, nH, F,
mF, µF, nF, pF, Ω, mΩ, kΩ, MΩ, or S, kS, mS, µS, nS, pS.
In the CORR menu, use the arrow keys
7
to se-
lect the LOADM function to set the reference value, press
the knob
6
(editing mode) and select the desired refe-
rence value via knob. By pressing the knob again, you can
activate the manual value input via numeric keypad. A va-
lue input window will be opened. You can use the numeric
keys to enter a value. After entering the value via keypad,
confirm the entry by pressing the ENTER key or by pres -
sing the knob again.
You can use the LOADS function (secondary measurement
value display) to save a reference value for the load impe-
dance LOAD in the reference memory LOADS. Depending
on the parameter FUNC, you can choose one of the fol-
lowing as unit for the measurement value: Ω, mΩ, kΩ, MΩ,
S, kS, mS, µS, nS, pS or °. In the CORR menu, use the ar-
row keys
7
to select the LOADS function to set
the reference value, press the knob
6
(editing mode) and
select the desired reference value via knob. By pressing
the knob again, you can activate the manual value input
via numeric keypad. A value input window will be opened.
You can use the numeric keys to enter a value. After en-
tering the value via keypad, confirm the entry by pressing
the ENTER key or by pressing the knob again.
The LOADM or LOADS function is not necessary for Hameg ac-
cessories. In this case, the regular OPEN /SHORT compensation
is sufficient.
You can use the parameters LOADM and LOADS if it is dif-
ficult to align a connect measurement adapter or if it is
connected to the bridge via long test leads. In this case, a
complete open or short circuit compensation is not pos-
sible because the bridge cannot compensate the actual
equivalent circuit diagram of the measurement adapter
with a simple equivalent circuit. This places the bridge in
a state that cannot be compensated. The user can com-
pensate the measurement error by means of a known im-
pedance with a given frequency. If the compensation with
a known load (LOAD) is activated, the bridge corrects the
measurement value of the connected impedance in rela-
tion to three impedances:
❙ Short circuit impedance,
❙ Idle time impedance
❙ Load impedance
It is possible to use up to 5 different reference values for
the load impedance which can be selected by means of
NUM parameter. An impedance always corresponds to a
group of parameters: a number, a frequency, a function
and naturally the known parameters of the impedance. Af-
ter the compensation with adjustment (LOAD), the impe-
dance is connected to the measured impedance to mea-
sure with the load impedance correction. Correcting with
a load impedance is most effective if the load impedance
is near the measured impedance. If the compensation with
adjustment (LOAD) is switched on (parameter LOAD set to
„ON“), the load impedance correction is automatically ac-
tivated when the set measurement frequency is equal to
the measurement frequency of the load impedance LOAD
which is saved for the load impedance corrections within
the 5 parameter groups. Therefore, it is important that the
5 parameter groups have different frequencies for the load
impedance correction.
7.3 Menu Function SYST
7.3.1 CONTRAST Function
You can use the CONTRAST function to set the display
contrast from 35 to 55. In the SYST menu, use the ar-
row keys
7
to select the CONTRAST function
to choose the screen contrast, press the knob
6
(editing
For a compensation with adjustment, a value is entered in both
reference memories (LOADM and LOADS) (e.g. for a real re-
sistance for LOADM the resistance value and the value "0" for
LOADS).
Fig. 7.9: Menu function SYST display