Omicron Lab Bode 100, User Manual, Page: 35 / 133

7.1 Gain measurement introduction
Bode 100 offers two different ways of measuring Gain. Either with the internal reference or the
external reference. Internal reference means that Receiver 1 is internally connected to the Bode 100
signal source picking up the source voltage. External reference means that Receiver 1 is routed to the
front panel input Channel 1.
Depending on the Receiver 1 connection, Gain is measured as shown in the following table:
Receiver 1 is set to internal reference Receiver 1 is set to external reference
Bode 100 measures
Where V
0
is the internal source voltage. If
Channel 2 is terminated with 50 Ω (default), Gain
equals the scattering parameter S21 of a two-port
DUT (Port 1 is connected to
Bode 100 output and
port 2 is connected to Bode 100 Channel 2).
If Channel 2 is set to high-impedance, a
Thru-connection from Output to
Channel 2 will result in +6 dB. To
normalize to 0 dB you can use Thru-
calibration.
Bode 100 measures
Gain therefore equals the transfer function of a 2-
port DUT if Channel 1 is connected to the DUT
input port and Channel 2 is connected to the DUT
output port.
The following two measurement modes can be used to perform a Gain measurement:
1. Transmission / Reflection : This mode allows both, measurements with internal and external
reference connection.
2. Gain / Phase : Is used to measure Gain from Channel 1 to Channel 2 (Frequency Response
Measurement).
Since the gain result is a complex number you can choose how gain shall be displayed. You can
select the result formats by clicking the drop down
Format in the trace configuration box.
Measurement types and applications
OMICRON Lab 35