Source Impedance - Stanford Research Systems DS360 Operating Manual And Programming Reference

3-10 Operation

Source Impedance

The source impedance of the DS360 can be set to different values. When the output of
the DS360 is terminated into the selected source impedance, the amplitude set on the
front panel will be the amplitude seen by the load. If the output is not terminated into the
selected load, the amplitude set on the front panel will be incorrect. If one of the source
impedance's is selected (not Hi-Z), and the unit is terminated into a high impedance, the
amplitude will be double the set value. The Hi-Z should be used when the output is
terminated into a high impedance. The Hi-Z amplitude will be correct (<1% error) for all
load impedance's larger than 5 kΩ.
The output impedance changes for unbalanced and balanced. Each output (positive and
negative) has the selected source impedance for unbalanced outputs. For balanced
outputs, each output has 1/2 the selected source impedance.
Source Impedance
The selected source impedance is displayed under the IMPEDANCE heading to the left
of the display. To change the impedance, press [SHIFT][impedance], where impedance
is either 50Ω, 150Ω, 600Ω or Hi-Z. It is not necessary to press an entry key to select
source impedance's.
If changing the source impedance from Hi-Z or 600Ω to 50Ω or 150Ω would cause an
out of range amplitude or offset, the following will occur. The DS360 will beep, display
the message Adj volt and adjust the amplitude to 14.4V
DS360 Ultra Low Distortion Function Generator
Source Impedance for + or - Output
50Ω
150Ω
600Ω
Hi-Z
Unbalanced
50Ω
600Ω
25Ω
and the offset to 0 V
PP
Balanced
25Ω
75Ω
300Ω
25Ω
.
DC