Convolution – Tektronix AWG610 User Manual

Page 444

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Appendix F: Miscellaneous

F-4

AWG610 Arbitrary Waveform Generator User Manual

Convolution

The operation expressed by the following equation is called convolution. With
respect to a discrete system, convolution y(n) of a certain waveform x(n) and a
second one h(i) is expressed by the following equation. N is the number of items
of data.

yĂ (n) +

ȍ

Nć1

l+0

x(i)h(nći)

Periodic. The Periodic enables you to specify whether the two-waveforms must
be regarded as periodic during calculation. Below is an example showing
differences between non-periodic and periodic waveforms.

Waveform A = a0, a1, a2, a3, a4

(5 points)

Waveform B = b0, b1, b2

(3 points)

For nonperiodic case:

A*B =

a0b0,

a0b1+a1b0,

a0b2+a1b1+a2b0,
a1b2+a2b1+a3b0,
a2b2+a3b1+a4b0,

a3b2+a4b1,
a4b2,

0,

(8 points)

The data length of the waveform created is the total of the number of points of
the two-waveform files.

For periodic case:

A*B =

a0b2+a1b1+a2b0,
a1b2+a2b1+a3b0,
a2b2+a3b1+a4b0,
a3b2+a4b1+a0b0,
a4b2+a0b1+a1b0,

(5 points)

Waveforms A and B are regarded as periodic during calculation. The count of the
operation of sum of products is equivalent to the length of the shorter waveform.
The resulting waveform’s cycle equals the same as the longer waveform. The
actually output segment of the waveform corresponds to one cycle. The starting
point value of the waveform equals the sum of products that is obtained with the
starting point values of waveforms A and B added.

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