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Chapter 38
Signal Generation VIs
Sinc Pattern
Generates an array containing a sinc pattern.
If the sequence Y represents Sinc Pattern, the VI generates the pattern according to the
following formula:
y i = asinc ( i ∆t – d ) , for i = 0, 1, 2,…, n–1,
sin ( πx )
where sinc ( x ) = ------------------- , a is amplitude, ∆t is the sampling interval delta t, d is
πx
delay, and n is the number of samples.
The main lobe of the sinc function, sinc(x), is the part of the sinc curve bounded by the
region –1 ≤ x ≤ 1.
When |x| = 1, the sinc(x) = 0.0, and the peak value of the sinc function occurs when
x = 0. Using l'Hôpital's Rule, you can show that sinc(0) = 1 and is its peak value. Thus, the
main lobe is the region of the sinc curve encompassed by the first set of zeros to the left and
the right of the sinc value.
Sine Pattern
Generates an array containing a sinusoidal pattern.
If the sequence Y represents Sinusoidal Pattern, the VI generates the pattern according to the
following formula:
y i = a sin ( x i ) , for i = 0, 1, 2,…, n–1,
2πi k πφ
where x i = ------------- + --------0- , a is the amplitude, k is the number of cycles in the pattern,
n
180
φ 0 is the initial phase (degrees), and n is the number of samples.
© National Instruments Corporation
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LabVIEW Function and VI Reference Manual