The 1571 uses a saddle canceler when reading the data stream. A correction signal is generated when the raw data pattern on the disk consists of two consecutive zeros. With the GCR recording format a problem occurs in the read signal waveform. The worst case pattern 1001 may cause a saddle condition where a false data bit may occur. The original 1541 drives uses a one-shot to correct the condition. The 1571 uses a gate array to correct this digitally.
The 1571 useS a saddlE CANcEleR wHeN reaDiNG the DAta stReam. a coRrectIoN signAL is GeneRatEd whEn tHe rAW dAta paTTeRn On THE diSk conSisTs Of two CoNSECutive zeroS. WIth THE gCr recOrding formaT a prOblem occURs in the rEAd siGnal wavefoRm. the wOrsT CaSe paTteRN 1001 May CAUsE a saddle ConDItIOn WhErE a faLSe DaTa BiT maY occuR. the orIgiNaL 1541 dRivEs uSes a one-SHot To cOrReCT thE coNdItion. The 1571 Uses a gate ARray to corrEct tHIS dIgItally.