Abstract: A tracking system and method are disclosed for a helical-scan recording device to automatically maintain the recording/playback heads in alignment with the stripes of recorded information on the magnetic tape. Each stripe on the magnetic tape includes a servo area having four distinct zones. An analog servo signal at a preselected frequency is recorded on one of the four zones on each stripe and is recorded at different ones of the four zones in succession on each group of four adjacent stripes. The servo signal recorded on the stripes is detected during playback and processed to maintain the desired head positioning relative to the stripes on the tape. The servo head is preferably maintained between adjacent stripes on the magnetic tape and signals detected from each of the adjacent stripes maintain head alignment by shifting the positioning of the head in either direction as needed.

Abstract: An improved amplitude sensing system for detecting the signal amplitude from the read head in a magnetic storage device wherein the signal amplitude is compared to a threshold voltage. When the signal amplitude is greater than the threshold voltage, the amplitude sensor output is high, indicating sufficient amplitude, and when the signal amplitude is less than the threshold voltage, the amplitude sensor output is low, indicating insufficient amplitude. The threshold voltage is selected to be the higher of a fixed minimum voltage, the minimum long term acceptable read head signal level, or an adaptive voltage derived from the peak voltages of the read head signal amplitude, which is a fixed percentage of the long term read head signal level. When the read head signal is not present for a long time, or while tape motion is starting, the fixed minimum voltage prevents invalid amplitude sensor output.