Rohde & Schwarz FSV3000, Руководство пользователя

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Common measurement settings
R&S
®
FSVA3000/ R&S
®
FSV3000
399 User Manual 1178.8520.02 ─ 08
Two-port mixer Three-port mixer
In both cases, the nominal LO level is 15.5 dBm.
Bias current
Single-diode mixers generally require a DC voltage which is applied via the LO line.
This DC voltage is to be tuned to the minimum conversion loss versus frequency. Such
a DC voltage can be set via the "BIAS" function using the D/A converter of the
R&S
FSV/A. The value to be entered is not the voltage but the short-circuit current.
The current is defined in the "Bias Settings" or set to the value of the conversion loss
table.
See "Bias Value" on page 413 and "Bias" on page 416.
The voltage U
0
at the output of the operational amplifier can be set in the range –3.3 V
to +3.3 V. An open-circuit voltage U
bias
of –0.75 V to +0.75 V is obtained accordingly at
the output of the voltage divider. A short-circuit current of I
short
= U
0
/ 260
Ω
= -12 mA to
+12 mA is obtained for a short circuit at the output of the voltage divider. In order to use
biasing it is not important to know the exact current flowing through the diode since the
conversion loss must be set to a minimum with the frequency. Therefore, it makes no
Data input and output