Diode circuits for pulse regeneration and multiplexing at ultrahigh bit rates

Clocked step-recovery diode (SRD) circuits are investigated for regenerating and multiplexing PCM-type signals in the range from 0.1 to a few gigabits per second. One regenerator type is particularly suited for operating with signals in the 1-V range, whereas a differential version employing a magic T was developed for handling signals of down to about 5 mV. By making use of line transformers as coupling networks, high-level versions have been cascaded. Experiments performed at 0.3 and 1 Gbit/s yielded voltage amplifications (peak amplitudes) of 2.5-5.5 for single stages, and insertion power gains of 7-11 dB for 2-3 stage cascades. Diode stages have also been used for multiplexing 4 and 2 individual bit streams to give a combined output signal at 1 and 2 Gbit/s, respectively. In a preliminary multiplexer experiment an output at 4.5 Gbit/s was obtained. Finally, possibilities are discussed for improving the performance of the regenerators/multiplexers and for their applications.