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RF SPECTRA of THOR with Signal Shaping

 

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Here are the?? RF Spectra ? of?? THOR22? (sent on 40m SSB)? when sent with? 0 (milliseconds) signal shaping and? 500 (millisec) signal shaping.

The shaping value is now in the FLDIGI MENU under? MODEM:? GENERAL??? and can be set manually from 0 to 500 value.


Shaping the signal amplitude tones in the FSK modes like THOR, MFSK, AFSK RTTY? should tend to "soften" them - resulting in a smaller bandwidth (like shaping a CW carrier)

On CW the shaping in milliseconds is typically 4-8 ms? (turning the carrier on/off) which results in a narrow bandwidth CW signal.

No shaping of a CW signal results in key clicks and a wide splatter type signal.


I'm not sure what the units are in FLDIGI for tone "shaping" but it also looks like milliseconds.

RF spectra captured with an SDR (RSP play) and RSP Spectrum Software


de k3eui


No Signal Shaping


500 ms Signal Shaping
 

Dave tells me that the “shaping” of Thor is for AGC and AFC and not to limit the bandwidth as I had surmised
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It only alters the first and the last tone and not every tone
?
de k3eui
?
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The newest alpha fldigi does have an option to adjust the rise/fall time of EACH Thor tone, which does slightly alter the bandwidth of the Thor signal (and other fsk modes)
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The choice of rise and fall timing is from 0 to 8 milliseconds
Modern rigs do the same for CW “shaping”
?
de k3eui

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