TRANSISTOR BINARY PULSE REGENERATOR 10G7 



2.1 Inhibiting in Blocking Oscillator 



The secondary of Ts is connected between the transistor base and 

 ground with the diode D2 and resistor R^ in series across it. The combina- 

 tion of diode and resistance across T^ serves a very important function, 

 the inhibiting of multiple triggering on a single input pulse. During the 

 interval in which the pulse is regenerated a negative potential is applied 

 between the base and ground. A current h flows through the base of the 

 transistor, the diode Do being poled to restrict the flow of current in 7?3 . 

 At the end of the pulse the current h in T^ drops suddenly to a low value. 

 This current change in the inductive winding of T3 induces a relatively 

 large potential across the base of the blocking oscillator. The impedance 

 of D2 becomes low and current flows in Rz and T3 . The potential across T-s 

 decays exponentially and with proper circuit values will take the form of 

 a damped cosine wave. 



E = Eoe~"' cos wo^ (10) 



I where t is the time measured from the peak of the pulse. The values of 

 a and coo can be adjusted by varying the inductance the transformer and 

 the capacity and resistance connected across it. E should become sub- 

 stantially zero at or near the next timing interval. The damping coeffici- 

 ent a should be sufficiently large to prevent an appreciable negative ex- 

 cursion of E since this will reduce the effective bias on the repeater and 

 consecjuently its noise margins. This will be further discussed in the sec- 

 tion on the measurements of errors. 



2.2 Quantized Feedback 



The quantized feedback is provided by coupling the input and output 

 transformers by means of resistances R. The fed back pulse must be in 

 the opposite phase compared to the input signal. 



2.3 Timing Wave Circuit 



The timing wave is derived by means of the parallel resonant tank cir- 

 cuit L2C5 which is tuned to the signal repetition frecjuency. The regen- 

 erated pulses are applied to this network through the relatively large 

 resistance 7^4 . The amoimt of energy added to the network by each pulse 

 as well as the amount dissipated in it is a function of Q. The higher the Q 

 the smaller will be the variations of timing wave amplitude as the aver- 

 age pulse density of the signal train changes. This does not mean that 

 the highest Q will be the most desirable for increased Q means larger, 



