BNC 645 User Manual
Page 165
165
-- V --
VOLTage {<amplitude>︱MINimum︱MAXimum}
Specify the output amplitude. The minimum value is 10 mVpp into 50Ω and the
maximum value is the largest amplitude for the chosen function (at most 10 Vpp
into 50Ω depending on the chosen function and the offset voltage).
z
The output amplitude and offset voltage are related to Vmax as shown
below:
|V
offset
| + Vpp ÷ 2 ≤ Vmax
Where Vmax is the maximum peak voltage for the selected output termination
(5 volts for a 50Ω load or 10 volts for a high-impedance load). The function
generator will take the new specified output amplitude, but the offset voltage
may be reduced accordingly, and a “Settings conflict” error is generated.
z
Output Termination Limits: When the Output Termination Setting is
changed, the Output Amplitude is automatically adjusted. For instance,
when you change the output termination from 50 ohms to “high
impedance”, your offset voltage doubles, thus it affects your output
amplitude, and when Output Termination has been changed from “high
impedance” to 50 ohms, the offset voltage decreases in half.
z
Output amplitude in dBm is not available when the output termination is
set to “high impedance”. The units will be Vpp.
z
For arbitrary waveforms, if the waveform data points do not span the full
range of output DAC (Digital-to-Analog Converter), the maximum offset
and amplitude will be limited.
z
Setting a high level and low level is another way to specify the output
amplitude. For instance, you will have an amplitude of 5 Vpp (with an
associated offset voltage of -500 mV) when you set your high level to +2
Vpp and low level to -3 Vpp.
z
While changing amplitude, you may notice a momentary disruption in the
output waveform at certain voltages due to switching of the output
attenuators. The amplitude is controlled, however, so the output voltage
will never exceed the current setting while switching ranges. You may use
the VOLT:RANG:AUTO command to disable the voltage autoranging to
prevent this output disruption.
z
To output a dc voltage level, select the dc voltage function using the FUNC
DC command and then set the offset voltage level using the VOLT:OFFS