The structure and properties of methylenetetrahydro-folate reductase from Escherichia coli suggest h

A tunnel diode pulse generator is triggered through a directional coupler. The tunnel diode is coupled across one end of an output transmission line through an impedance matching network which matches the characteristic impedance of the transmission line. Triggering signals are coupled to the transmission line through the directional coupler for propagation of triggering impulses towards the tunnel diode.