AN ALGORITHM FOR A REAL-TIME MEASUREMENT OF NONLINEAR TRANSITION SHIFT BY A TIME-DOMAIN CORRELATION-ANALYSIS

An algorithm has been developed for a real time measurement of the non linear transition shift in high areal density magnetic recording, by a time domain correlation analysis. By measuring SNR and a correlation coefficient of the time domain readback voltages, r[v(t), v(t + epsilo n /2 + (M(1) - 1/2)T)], written by a pseudorandom sequence, we can det ermine the nonlinear transition shift in real time. This new algorithm not only simplifies data processing of the readback waveform, but als o includes noise effects on the nonlinear transition shift measurement . This algorithm has been implemented by LeCroy Corporation into their 7200-A high-speed digital oscilloscope. The LeCroy oscilloscope measu res the nonlinear transition shift in less than 100 ms utilizing this algorithm.