But even if the RX bandwidth is wide enough that there is negligible
distortion, you can't distinguish dits that are 5 ms long if the rise
time is 2 ms.
73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/
On 30 Mar 2016 07:17, Jim Brown wrote:
On Tue,3/29/2016 1:03 PM, Vic Rosenthal 4X6GP/K2VCO wrote:
The relationship of bandwidth and speed is that for given rise/fall
times, increasing speed will reach a point when the code elements blur
together.
Yes, but that's RX bandwidth, VERY different from occupied bandwidth.
The issue is RX bandwidth is the TIME (phase) response -- every change
in amplitude is accompanied by a change in the phase response, that that
phase distortion (remember, phase is time) blurs the code elements
together.
So you need more bandwidth for super high-speed CW because you need to
shorten the rise and fall times.
You need more RX bandwidth, for the reason described above.
But the occupied bandwidth doesn't change as you vary the speed.
Right. Occupied bandwidth is your "footprint" on the band -- how much
your signal is spread out.
73, Jim K9YC
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