Clock signal regeneration system for 155 Mega bits per second NRZ in digital cross=connection exchange matrix - has phase regulator and quartz filter, which works on fifth harmonic to coincide with bit rate

摘要

A signal is fed to a quartz (Q3) whose output (1) is supplied to a clipper (SQ) comprising a pair of transistors (TR5 and TR14) acting as a differential amplifier. The desired clock signal (CK) is obtained (on CKDB and CKDBN). The excitation signal at ECL level obtained from NRZ data, is applied to the circuit through a resistor that drives in current the filter (LC) tuned on the frequency to be extracted. The resistive impedance presented at resonance by the filter, added to the one of the polarisation inductance of the clipper differential downstream of the circuit, is placed in series with the quartz resonating at the same frequency, reducing its Q from 10,000 to about 1,000. The result is a sole filter with a Q of value suitable to the use.