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Modulate a current up to 100MHz



Jan 1, 1970
Hi, I am using the following basic and simple circuit to bias a sine

+/\/\/\+ Vcc
-- INPUT -- ||------+------------+------------------------> OUT
C | +/\/\/\+ GND
\ R2
/ R1
_+_ GND

with C=50pF and R1=50Ohm to match the impedence of the signal generator and
to avoid the DC reach its output. Well I adjust R2 and R3 for the correct

Now I need to build a current source driven proportionally with this voltage
I have signal up to 150MHz, current up to 350mA and the load is a LED. Which
transistor can I use? In which configuration? Well.... in which manner can I
optimize the LED driving considering that their resistence and capacitance
can limit the bandwidth of the circuit?

Moreover, well, I have a post in another NG but I take advantage of this
post to renew here the question.
For another application I need to convert this sinewave into a squarewave
(possibily with adjustable duty-cycle). I got some elegant solution as PLL,
Line receiver, ... but due to my limitation (in general for my rusty
electronic) and in particular about the tools I have available, I prefer
some simpler solution. I think a trigger-schmitt with two transistor can be
enough. Any suggestion also regarding this subject? I need packages non-SMD
that I can manage with my low-tech soldering tool :) I will try also with a
74ALS04 to make a trigger I need... bit I am open to other