Re: How many joules --> e.m. waves?

[inet@intellisys.net (brian whatcott)]

At 11:31 AM 4/23/97 EDT, LUDWIK KOWALSKI wrote:
>                                    Three questions:
> On 22 Apr 1997 Bob Sciamanda wrote:
>
> > Your "rig" is putting out a broad band signal; I don't expect much of a 
> > tuning effect over a broad range of the receiver "dial"!
>
> We have a well defined LC circuit with low R. Thus the frequency band of 
> the oscillating current is very narrow. Why would the e.m. wave emitted by 
> the wire loop have "a broad band"?  
> ...
>                                                         Ludwik Kowalski
An easy way to visualise this effect of signal shape on bandwidth
is to start with a very narrow pulse ( A 'Dirac' function even...)
 It is not difficult to understand that a wide band of  frequencies
is emitted.
 Then if this pulse is broadened to one cycle of a given frequency
 the  emitted bandwidth is reduced.
    If we proceed to a train of 10 cycles, the bandwidth decreases
again,  until at a continuous sine wave, the bandwidth narrows to a
'line' emission.

regards
brian whatcott <inet@intellisys.net>
Altus OK