I've tried a very simple switch with a NPN & a PNP plus some resistors and a
diode, but the result hasn't been as expected, and the efficiency is quite low.
Besides, a 1 KOhm load resistor is needed in order to increase the switching ti-
me (from 36V to 24).
I would prefer to limitate the emission of the circuit, that is, the switching
shouldn't radiate too much.
Any one can help me? Any proposal is welcome
You would be better off using a frequency division multipex system. At each end split the line into high and low frequency outputs. (Inductor to the power path and capacitor to the signalling path.) Use fsk on a vco at the sending end and a PLL at the receiving end for the data.
I don't want/need a fsk modulation (this would complicate my design), actually, my design suports this low baud velocity (9600). I was thinking in a Mosfet conmutation with some second order circuit to attenuate the switching noise.
How about putting a regulator on the load end to eliminate the noise. Then use a series zener and a FET to short it out. This will give you the two voltage levels. Then at the load end use a voltage divider to get the levels down and then put it to a comparator.
But, how could be the schematic of the switching source?,
Actually at the end load, as you say , I put a TRT as a comparator to read the transmition...
My design is like yours, using npn & pnp bipolar transistor, but the switching induces a lot of noise of radiated emi, and it requires a load in the line.
I was thinking to implement it with power mosfets to reduce emi (or a ressonant circuit).... i don't know....