On Oct 20, 2005, at 3:28 PM, Joe Subich, W4TV wrote:
> The FT-990, FT-1000D, FT-1000MP, mark V, Field, etc. are actually
> AFSK even in "FSK." Yaesu generates FSK by feeding an audio
> tone into the balanced modulator. The audio tone is generated
> in a phase continuous audio synthesizer.
At one time, G3SEK and I checked the schematics very carefully, and
had reported to this reflector.
My FT-990 is definitely Keyed FSK (i.e., FSK interface, but an
internal AFSK generator that feeds an SSB modulator).
However, both Ian's FT-1000MP and my FT-1000MP appear to be direct
FSK. The FSK keying signal goes into an DDS chip. There is no AF
signal coming out of that chip, just synthesized RF.
I haven't found a FT-1000D schematics to look at, but I suspect it,
like the 990, is also Keyed FSK.
73
Chen, W7AY
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