B&K Precision 4079 - Manual - Manual (Page 40)

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3.14.4 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:
𝑟𝑎𝑡𝑒 =
1
1000 𝑝𝑡𝑠 ∙ 1000 𝐻𝑧 = 1 𝜇𝑠
EXAMPLE: Setting the Output Frequency
To set the output frequency of a 1000 point waveform in execution memory to 1000 Hz, set the rate to 1 µs:
ACTION KEYSTROKES
Step 1. Set the output rate to 1 µs (equivalent to PARAMETER
1000 Hz output frequency) F1 :RATE
1
KHz/us
3.14.5 Setting the Amplitude
The following equation represents the relative output amplitude voltage relationship between the front-panel amplitude peak-to-
peak setting and the data point values in waveform memory:
𝑜𝑢𝑡𝑝𝑢𝑡 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 =
𝐴𝑚𝑝𝑙𝑖𝑡𝑢𝑑𝑒 𝑝 − 𝑝 𝑠𝑒𝑡𝑡𝑖𝑛𝑔 ∙ 𝑑𝑎𝑡𝑎 𝑝𝑜𝑖𝑛𝑡 𝑣𝑎𝑙𝑢𝑒
16382
+ 𝑜𝑓𝑓𝑠𝑒𝑡
Where 16382 is the total data point value range in waveform memory.
Table 3-4: Relative Amplitude for Waveform Output (Examples)
Front Panel
Amplitude Setting
Data Point Value Relative Output
Amplitude Voltage
5 V peak-to-peak 8191 2.5 V positive peak
5 V peak-to-peak 0 0 V (offset voltage)
10 V peak-to-peak -8191 5 V positive peak