This is my first time posting on this forum, so please bear with me. I'm trying to design a 'logic converter' to convert a signal from one logic standard to another, and vice-versa. The first logic standard is the Nuclear Instrumentation Module fast logic standard (NIM logic), whose logic voltages are 0 volts when low and -0.8 volts when high, and it remains high for only 10 nanoseconds. The other logic standard is the TTL standard, 3.3 V when high and 0 V when low. The inputs can also be seen as 50 Ohm line outputs depending on the direction. In terms of power supplies available, the module that will power this circuit has +6, 0 (GND), and -6 volts to work with.
I'm trying to start off by converting the NIM logic to TTL logic. My thought was that I can first boost the NIM logic signal to something higher, and then use that larger voltage to activate a switch to provide the 3.3 V output as needed. For example, I boost the input so it reaches 0 V and -1.8 V, which then activates a PMOS switch to provide a 3.3 V signal accordingly. The issue is that with such a small input voltage, it's not enough to activate a PMOS (specifically the ALD 1107), so I thought I had to use BJTs to get the fast switching necessary. I tried simulating it with a current switch (emitter coupled), but it doesn't seem to reach the appropriate low logic level needed.
The circuit shown is what I have so far, and I'm simulating it through LTspice. I have very little experience designing circuits like this, and I'm not sure what else I can do to approach this problem. The time to switch is in nanoseconds, and I'm not even sure if my choice of BJTs is appropriate for the time needed. Power isn't a problem right now; I'm just trying to see what I can do to get it working. Are there any other kinds of circuits that would be helpful to look at given the goals?