I designed a Schmitt Trigger with discrete components (using an emitter-coupled pair) that operates with a Low Disable Trigger of around 3.5V and a High Enable Trigger of around 4V on circuit simulation. The circuit simulation uses a sine wave function generator to simulate a changing analog waveform.
The desired output of the Schmitt Trigger for high and low are 5V and 0V respectively, but this Schmitt Trigger outputs a logic high of 5V and a logic low of 3V, which is not suitable for the rest of my circuit, as they require 5V-0V logic levels to work.
The question is how can I make the Schmitt Trigger output a logic level of 5V-0V from a logic level of 5V-3V? What circuit can I "bolt on" to this design to make it output that logic level, or even better, an entirely different circuit altogether that achieves similar functionality (a discrete-component comparator that can achieve a 5V-0V logic level is also cool with me).
Keep in mind that I cannot use any ICs due to project requirements, and I also cannot use any other power supply other than 5VDC.