User Manual

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5.2.11 Output Termination/External Load
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. If output termination is greater than 10kΩ, the error will be
less than 0.5％. But if change output termination too lower, the actual volts will be not agreed with
displayed value.
In order to make actual volts be agreed with display value, you should set output termination when
it’s too lower. Press 〖Load/High Z〗softkey, if select High Z, output termination of waveform
generator must be ‘high impedance’ (>10kΩ), if select ‘xxΩ’,output termination can be set within
range of 1Ωto 10kΩ.
When setting value of output termination is equal to actual value, the actual volts value at the load is
in line with display value.
You must notice that most output termination are not resistive, because the inductive impedance and
capacitive impedance vary with frequency, especially when frequency high, that the variation can’t be
ignored. If you don’t know the actual impedance of output termination, you can change the setting of
‘Load’ and make the actual volts are in line with displayed value, then final setting value for ‘Load’ is
the actual impedance.
5.2.12 Output Control
The waveform generator has a output impedance of 50Ω, and it won’t be damage if 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.