Datasheet

22
5.2.12 External Load
In continuous mode, press 〖Output Menu〗and then〖Load〗softkey to set the external
load.
(1) The waveform generator has a fixed output impedance of 50Ω, the actual volts
value at the load is the standoff ration that load impedance to 50Ω. If change output
termination setting to higher, the standoff ratio will more approximate to 1, the error
between actual volts at the load and displayed amplitude or offset will become more
less. But if external load too lower, the actual volts will be not agreed with displayed
value.
(2) In order to make actual volts be agreed with display value, you should set suitable
external load.
Press 〖50Ω〗key to set external load as 50Ω.
Press 〖High Z〗key to set external load as High Z.
Press 〖Impedance〗key to set external load as desired value.
When setting of external load changes, the amplitude and offset display also
changes, but the actual output never change. Now you connect an external load to
output termination and make the actual value equals to setting, the actual voltage on
load will be same as the displayed value.
(3) When power on, the default external load is High Z.
(4) Note that most output termination are not totally resistive, because the inductive
impedance and capacitive impedance vary with frequency, especially when
frequency high, that the variation can’t be ignored. If actual impedance of output
termination are not confirmed, you can change the setting of ‘Load’ gradually and
make the actual volts are in line with displayed value, then final setting value for
‘Load’ is the actual impedance.
5.2.13 Output Control
The waveform generator has a output impedance of 50Ω, and it won’t be damaged once
instantaneous short-circuit. If an excessive external voltage is applied to a front-panel
channel output connector by an external circuit, the instrument will disable the output and
generate an error message with sound alarm. To re-enable the output, remove the
overload from the connector and press 【Output】key to enable output. But this function
is not absolutely safe, and long-time short circuit or too excessive external voltage is
forbidden.