BNC 645 - Manual (Page 26)

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•
Figure 3-8
• Limits with amplitude and output termination: DC offset value is
constrained by the equation below:
2
Vpp
Vmax Voffset − ≤
where Vmax is the maximum peak voltage allowed for the
selected output termination (5 volts for a 50 Ω load or 10 volts for
a high-impedance load).
If the specified dc offset is not valid, the waveform generator
automatically adjusts it to the maximum value allowed with the
specified amplitude.
• Arbitrary Waveforms Limitations: 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.
• For dc volts, the output level is actually controlled by setting the
offset voltage. You can set the dc level to any value between ±5
Vdc into 50 ohms or ±10 Vdc into an open circuit.
3.7 To Set High-Level and Low-Level Bounds
Setting high-level and low-level bounds provides an equivalent way to
specifying amplitude and DC offset. The procedure is as follows.
Front-panel Operation
1. Select your desired function by pressing one of the function keys.
2. Press the softkey under Ampl/High to toggle and make sure the
High is highlighted. Use the numeric keypad or the knob with
cursor keys to change the value.
3. Press the softkey under Vos/Low to toggle and make sure Low is
highlighted. Use the numeric keypad or the knob with cursor keys
to change the value.