Tektronix AWG610, User Manual

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Appendix D: Sample Waveforms
AWG610 Arbitrary Waveform Generator User Manual
D-5
Table D-7: Nyquist pulse
File name NYQUIST.WFM Made with equation editor
Equation clock = 1e9
size = 1024
k0 = 50e-9
'data period
k1 = 512e-9 'peak location
a = 0.5 'excess bandwidth factor 0 to 0.5
t" = (time - k1) / k0
nyquist.wfm" = cos(a * pi * t") / (1 - (2 * a * t") ^ 2) * sinc(pi * t")
delete (t")
Descriptions This is the impulse response of a wave shaping Nyquist filter. The
shoulder characteristics of this filter are referred to as cosine rollĆoff"
characteristics, and the bandwidth used can be varied. This waveform
can be expressed by the following formula.
V(t)
+
cos
ǒ
pa
t
T
Ǔ
1–
ǒ
2
a
t
T
Ǔ
2
@
sin
ǒ
p
t
T
Ǔ
p
t
T
Here T is the data period and a is a value between 0 and 1. A wider
band is required for values closer to 1, where ripple is reduced and
implementation is easier.
Settings Waveform points: 1024, Clock frequency: 1.0 GHz,
Output time: 1024 ns