Rectangular pulse and Modulated Filter.
Here a pulse of width t is passed through a filter
with transfer function (1 + a cos(nwt
/2b)). The limits of the filter are ±b2p/t.
The output has 2 pulses of amplitude a/2 on either side of the incoming pulse separated by
nt/2b from the main pulse.
The effect is illustrated in the applet below. The applet shows one pulse
being advanced in time, however a real filter will have a phase delay which will
shift everything to the right. In the applet b is R.F., a is Amp and n is Har.
Magenta curve shows the incoming pulse, red curve shows the transfer function of the
filter, cyan curve is the spectrum of the incoming pulse , yellow curve is the
output of an ideal filter and green curve shows the output of the modulated filter.
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COPYRIGHT © 2005 Cuthbert Nyack.