B&K Precision 4078 - Manual - Manual (Page 37)

* Draw lines between data points
* Create a predefined waveform
* Export waveform from software
* Create data points using SCPI commands
* Combine any of these methods
The waveform’s frequency and amplitude are influenced by the number of data points and their value in the waveform.
For further information on how the number of data points influence the frequency and amplitude of a waveform in
execution memory, see Setting the Frequency portion (Section 3.14.3) and Setting the Amplitude portion (Section
3.14.4), respectively.
3.14.2 Entering Individual Data Points
The most basic way to program an arbitrary waveform is to enter data points for the waveform, one data point at a
time. While this can become tedious, the auto-increment function helps this process.
To enter individual data points into waveform memory, follow these steps:
1. Press ARB main key to display the selection menu.
2. Press F2: ARB to display the arbitrary menu.
3. Press F4:EDIT to display the Edit menu.
4. Press F1:POINT, to select the point by point programming mode.
5. Press F1:ADRS
6. Use the rotary knob or the numerical keypad to enter the address.
7. Press F2:DATA.
8. Use the rotary knob or the numerical keypad to enter the value for the data point. Valid entries range
from –8191 to 8191.
9. Repeat steps 5 through 8 for additional points until you finish creating your arbitrary waveform.
Note: Each time you press ENTER to complete a data point entry in numerical mode, the auto-increment
address advances the "A= value" by one.
3.14.3 Setting the Arbitrary Frequency
The arbitrary waveform frequency is a function of the number of data points used to run the waveform (the length
parameter in the ARB menu) and the waveform execution point rate. The waveform execution point rate is the
execution time between each point in the waveform. The total time taken to run one period of the waveform is
given by:
𝑇𝑜𝑡𝑎𝑙 𝑡𝑖𝑚𝑒 = # 𝑜𝑓 𝑝𝑜𝑖𝑛𝑡𝑠 ∙ 𝑟𝑎𝑡𝑒
Because the output frequency is a function of the rate and the number of points being executed, the output frequency is
calculated as:
𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 =
1
# 𝑜𝑓 𝑝𝑜𝑖𝑛𝑡𝑠 ∙ 𝑟𝑎𝑡𝑒
For example, to set the output frequency to 1000 Hz, given the number of data points used for the waveform output is
1000, the rate is calculated as: