[RTTY] FW: OO Advisory kk5oq

[Kok Chen]

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