I obviously am confused about the meaning of bandwidth. Thanks for your replies.
Bandwidth, like happiness in the old song, is "different things to different people".
(1) Occupied spectrum of a signal--- for instance, if displayed on a Spectrum Analyser, an AM Medium Frequency Broadcast Station in Australia will occupy around 18kHz of spectrum around the Medium Frequency carrier ( other countries may vary), whereas a VHF Stereo Broadcast transmission will occupy around 200kHz.
(2)The range of frequencies which may pass through a device, whilst the device maintains the same gain or loss-- the "bandwidth" of the device.
(3)As Yada says above,
" a measure of how much information was contained in the signal" .
In simple amplifiers & modulation systems, there is a direct relationship between this & bandwidth as in (1), but with sophisticated modulation systems it is possible to send a lot more information with the same occupied spectrum.
With the proliferation of computer equipment, the original meaning of (1) & (2) have been blurred due to the propensity of IT people to refer to bandwidth as
"bit rate or throughput, measured in bits per second (bit/s)".
Marketing people, of course, stomp across every one of these meanings with hobnailed boots!
https://en.wikipedia.org/wiki/BandwidthEverybody leapt in with both feet to lecture the OP about the instrument bandwidth necessary to display 100MHz
square waves.
Apparently, they didn't notice the reference to
RF.
Far from needing to see harmonics of the fundamental, out to
5f, in RF work, we want to minimise harmonics!