REGENEKATION OF BINARY MICROWAVE PULSES 



85 



as the input voltage in a branch reaches a vakie equal to that of the back 

 bias the diode will start to conduct, thus absorbing power and decrease 

 the slope of the characteristic. The output of Branch 1 starts to flatten 

 off when the input reaches the value Vi , while the output of Branch 2 

 does not flatten until the input reaches the value V2 . The combined 

 output, which is equal to the differences of the two branch outputs, is 

 then that shown by the solid line of Fig. 15C and is seen to have a transi- 

 tion region between a low output and a high output level. If the two 

 branches are accurately balanced and if the signal voltage is large com- 

 pared to the differential bias V2 — Vi the transition becomes sharp and 

 the device is a good slicer. 



If the two diodes are equally biased as shown on Fig. 15D the outputs 

 of the two branches should be nearly equal regardless of input and the 

 total output, which is the difference between the two branch outputs, 

 will always be small. 



Fig. 16 shows a microwave equivalent of the circuit of Fig. 15A. In 

 the microwave structure lengths of wave-guide replace the wire lines and 

 branching, recombining and isolation are accomplished by means of 

 hybrid junctions. The hybrid shown here is of the type known as the lA 

 junction. 



Fig. 17 shows another equivalent microwave structure employing only 

 one hybrid. This is the type used in the experiments described here. The 

 [output consists of the combined energies reflected from the two side 

 jarms of the junction. With the junction connected as shown phase rela- 

 Itionships are such that the output is the difference between the reflec- 



GATING 

 PULSE 



^(— r-V\^^^ 



RF 

 INPUT ARM 



PROBE 



TERMINATION 



I 



ARM 4 



I— vw-^ 



Fig. 16 — Microwave regenerator. 



