I figured that your timing was based on a clock, but maybe with the pulse with to voltage scheme, jitter won't be a problem. That is, whatever initiates the timing pulse will have jitter, especially if it is based on a crystal clock (and what isn't). However, the exact start time of the pulse shouldn't matter, just the pulse width.
Hello Mike,
When I was a student I often rolled my own (and then sometimes spent the saved money in the pub...). If you have the time this provides a learning opportunity far beyond what a university can offer. The design, that is, not the pub ;-)
However, be careful. Saving $10 and then frying a $300 laser diode because of a slight circuit bug would not be such a good experience. Happens easily. Something bursting into oscillation, loop instability etc.
Study the diode's data sheet carefully. Many laser diodes cannot be run without cooling, at least not for too many milliseconds. Plus it will complicate the diode current regulation if your temperature is all over the place.
-- Regards, Joerg http://www.analogconsultants.com
Hello Win,
Even with a common base transistor up front from the transimpedance amp?
Maybe the photodiode would benefit from a strict current coupling for the amp (like into the emitter of an RF transistor) instead of a 50ohm link. Guess if that was more than 10 years ago the whole amp would have to have been discrete as well.
-- Regards, Joerg http://www.analogconsultants.com
Mike, important question, are you going to turn the laser diode on and off or just modulate it within the laser emission region? The diode properties make a difference in the required properties of the drive circuit.
-- JosephKK Gegen dummheit kampfen die Gotter Selbst, vergebens. --Schiller
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