3156B User Manual
Racal Instrument © 2005
Using the Instrument 3-25
Standard waveform frequency is measured in units of Hertz (Hz).
Arbitrary waveform sample clock frequency is measured in units of
Samples per second (S/s). The frequency of a given arbitrary
waveform at the output connector must be computed using the sample
clock frequency and the number of data points. Use the following
equation for computing the frequency of (one cycle of) an arbitrary
waveform:
Frequency = Sample Clock / Number of data points
For example, using a sample clock of 80 MS/s with a 1000-point
waveform will generate 80kHz waveform at the output connector.
The following function call sets the sample clock frequency for the
arbitrary and sequenced waveforms:
ri3156B_set_arb_sampling_freq
()
Sampling clock frequency can normally be programmed throughout
the range of 1S/s to 200MS/s however, on one condition, that the
number of points in any waveform is a multiple of 2 points. For
example, waveform length of 25804 can be used throughout the entire
range but if you increase the number of point by 1, it will only work
with a special sample clock range that operates from 1S/s to 100MS/s.
Before you decide which of the sample clock ranges you can use,
check all of your waveform files. For even number of points, use the
normal range, for odd number of points you can use the limited range
only. Select the sample frequency range using the following function
call:
ri3156B_set_arb_sampling_freq_range
()
Figure 3-7 demonstrates how easy it is, using a graphic interface, to
select the sample clock range (1), select waveform format (2) and
program the sample clock frequency (3), all are done with a click of a
mouse button.
