The ALPHA FLDIGI (4.2.06.19)?? as of Jan 05
2025
The? THOR? alpha (test) modes now have the?? OPTION ? to
include "signal shaping" from 0-8 milliseconds.
This is the rise/fall time of each tone
change.
It should operate in a similar way that the CW
carrier shaping limits the CW bandwidth and reduces "key
clicks" (older rigs).
Can we "see" or hear the changes when?? THOR?
signal shaping is turned ON or OFF?
Here is THOR? TX tone rise/fall times? signal
shaping set to a? 0 ms rise time? (no signal shaping at all)
in the Fldigi MENU
?? 
Here are the? OSCILLOSCOPE? trace (on Fldigi
WF)? and the ? RF Spectra ? captured when I was sending a?
THOR25 signal without signal shaping.
I can't hear the difference (in headphones) but
the RF Spectra? trace does show a cleaner skirt on the RF
signal.
The OSCILLOSCOPE trace has obvious differences
in the tone change amplitudes.
No signal shaping Oscilloscope Trace of THOR25
?? (signal amplitude vs. time)
THOR 25 RF Spectra reveals an??? 800 Hz BW???
at? -30 dB below the peaks.
Now with an? 8 millisecond signal
shaping turned? ON? (TX tone rise time (milliseconds)
Note:? using THOR 25? (25 tones/second)? EACH?
tone ? DURATION? is? 1/25? or? 40
milliseconds.
Oscilloscope Trace:? each tone is about? 40
milliseconds? with an? 8 ms? rise/fall time
The ? RF bandwidth ? of THOR 25? is
reduced by about? 100 Hz? (@ -30dB down)? from 800 Hz to 700
Hz? due to the tone "shaping"
K3EUI Barry