Current pulse detection circuit
I would look at what is known as a current loop receiver.  There are standards that operate from 4 mA to 20 mA, one example is the BB (now TI) RCV420.  It's likely you could adapt a similar IC since that one might be EOL (End of Life)

Because it is it a current loop signal having larger voltages is OK so having larger sense resistors makes your life way easier, rather than a \$ 1 \Omega\$ resistor.



Here is a snip from that datasheet to give you some ideas if you want to implement it in op-amps.

Looking at that datasheet it says that the maximum current is 30 mA, which I suspect means that you design criteria probably match that standard.