This trigger uses two switching transistors that can still be found with some ease. The circuit is from an old documentation and its purpose is to speed up the switching of logic circuits.
Analog Devices AD7768 24-bit sigma-delta (Σ-Δ) ADCs include an Σ-Δ modulator and digital filter...
The RC network of this circuit determines the operating frequency. The emitter-coupled circuit was found...
The operational amplifier used in this circuit is no longer very common, but the configuration can be adapted...