On 3/20/02 9:36 AM, "Ronald A. Stunden" <sparks@quik.com> wrote:
> The FT 990 is for sure FSK as I have been using it for some time...VE7YC
If you look at the schematics (AF-UNIT F3178000A) of the FT-990,
you will see that the RTTY Key line is used to key a digital sine wave
oscillator whose output is binary encoded voltage levels, with 8:4:2:1
resistor weights feeding an op amp, whose output is controlled by
the RTTY-Level pot.
The FT-990 not an FSK rig, it is a keyed-AFSK rig.
The only rigs which I have used that are FSK are the Omni V and
the Omni VI. With those, you have to occasionally go in and adjust
a trimmer to get the shift re-adjusted to 170 Hz.
73
Chen, AA6TY
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