"Jeff" wrote ...

Nope, you haven't the slightest bit of understanding of what the term
"passband" means so your question is nonsense.

"Radio receivers generally include a tunable band-pass filter with a
passband that is wide enough to accommodate the bandwidth of the radio
signal transmitted by a single station."

That statement is at best misleading, and in some cases incorrect.

In most receivers any *tunable* filter is MUCH MUCH wider than the
bandwidth required to accommodate the bandwidth of the signal transmitted.

The selectivity being produced by one or more *fixed* frequency filters
which are just wide enough to accommodate the bandwidth of the wanted
signal.


For me a radio is a box with the knob to rotate.
Now at FM no brakes between stations. At AM are.

What was in 1915?
S*


In 1915 there were no broadcast stations to speak of so your dial would
be just one large "brake" (sic).

"Well, it's like this. The story starts in 1915, when mankind discovered
sidebands. Now possessing this superior understanding of the AM signal,
radio scientists began to understand the implications of their discovery.
Soon afterwards, our old friends at Bell Labs, who have discovered
practically everything, developed a method for removing one of the sidebands
of an AM signal but retaining all the essential modulation components. As an
expert of that day supposedly said, "both sidebands are saying the same
thing" (Goodman, 1948). " From:
http://www.hamradiomarket.com/articles/SSBHistory.htm

If in 1915 were no broadcast stations to speak tell us what was with the
first station to speak and when it start transmitting.
S*