>@9
Multitone Audio Test System
User Manual
V 3.32
13 / 71
Connections between an unbalanced DUT
and the balanced inputs of
>@9
should
preferably be made with shielded twisted
pair cables to avoid the introduction of
noise and hum. The shield of such a cable
shall be grounded only on one side.
Grounding the shield on both sides
increases the chance to build ground loops.
Balanced Connection
Balanced connections with two BNC cables can be realized by connecting them to the
>@9
HIGH and LOW inputs. The ground shells of both connectors are wired to ground. Do not
connect the shields together on the instrument side of the DUT but leave them open. With
balanced connections do not assemble the short circuit bar.
You may also use banana inputs instead of BNC inputs. The respective HIGH and LOW
inputs of the BNC and banana connectors are internally wired together.
Caution: For balanced signals make sure that not only the front ground connection
is disassembled but also the ground bar at the rear panel!
Unbalanced Connection
If you use the HIGH input only of
>@9
for connecting the hot output of the DUT,
use the BNC cable’s shield as the return
signal (common of the DUT output).
When using the generator in unbalanced
mode, the available level will always be
6dB (50%) below the defined level.
Battery Low Indication
>@9
contains a battery for backup purposes of the internal memories. Life expectancy of
the battery is about ten years. Should the battery become low, the 'Error' LED will blink 3 to 4
four times after a start-up and
Error 220 Battery low (memory backup)
is generated.
Fig. 4 Shielded Twisted Pair Cable
Fig. 5 Balanced BNC / Banana Connection
Fig. 6 BNC Cable - Balanced
Fig. 7 Unbalanced Connection
