Tegam 2711A, Operation Manual

Page: 22 / 98

32 - 3
2
The Y values of the starting and ending points in your waveform can cause
unexpected discontinuities if they are not the same value. The waveform
generator output will jump from the ending value to the starting value each
cycle. If you are using the sequence generator in an arbitrary waveform
generator, the ending value of a waveform will jump to the starting value of the
next waveform in the sequence. For a smooth, transient-free waveform output,
be sure the starting and ending values are the same for a single waveform and
the starting and ending values of adjacent waveforms are the same for a
sequenced waveform.
Other Considerations
More on Waveform Cycle
TEGAM 2711A arbitrary waveform generator may sample the data points up to
a maximum of 2 MS/s. The maximum frequency of the output is determined by
the sample rate divided by the number of points. For a 2 MHz arbitrary
waveform generator with a waveform length of 1000 points, the upper frequency
limit appears to be 2 kHz, since 2 MS/s / 1000 = 2 kHz. However, if you repeat
the segment, such as a sinewave, up to the minimum required number of
samples (4 samples/segment), you can replicate up to 250 segments within the
waveform length of 1000 points. Then, the output frequency of the sinewave
will be 500 kHz, since 2 kHz x 250 = 500 kHz.
Whenever possible range the Y-values of a waveform between -32768 to
+32767 in the memory to obtain maximum resolution and to maintain the
desired dc integrity of the signal. WaveWorks Jr. allows you to normalize any
waveform in its Y values by a simple command. For instance, if you have a
sinewave in the waveform window that ranges from -32768 to +32767 you can
specify the output at 5 volts peak-to-peak. Automatically the -32768 relative
amplitude will be scaled to -2.5 volts and the +32767 relative amplitude will be
scaled to +2.5 volts. The sinewave will be centered around zero volts. The
desired output voltage may be set on the front panel of the generator or on the
Download Setup form before the waveform is sent to the 2711A.
If you set the output amplitude to 10 volts peak-to-peak and then you download
a waveform with Y-values b16384 and -16384, you have the same
+/-2.5 volt sinewave output. It is very important to understand the differences
between digital scaling and analog scaling. See the following page for the
illustration.
Chapter 2 About arbitrary waveforms
More on Waveform Cycle
Digital and Analog Scaling