[Laser] TX Circuit for high speed data.

[James Whitfield]

From: "Chuck Hast"


> I have been working with the K3PGP TX circuit to run high speed data. I
have
> found that when my data speed goes much above 150Khz the data starts
> getting rounded off........  Is there any problem with removing the 1K
resistors
> and driving the gate directly with the TTL buffered data output? ....

Sorry to reply so slowly.  It took me a while to look up the schematic on
the circuit.

I suggest that you try a capacitor between the modulation input and the gate
of the FET to restore the rounded off waveform.  Selection of value would be
a trial and error method, but I suggest that you start with a capacitor that
will have one tenth the reactance at the desired data rate as the resistance
of the two 1K resistors.  It probably will not push the data rate to 10 MHz
like bypassing the resistors completely, but should not offset the operating
point of the circuit as much either.

Best Wishes.

James
 n5gui