HP C2233 Product Description Manual page 55

Servo Processor
The servo processor provides index and start-of-sector
timing signals, and controls actuator movement, motor
spin-up and speed control, and synchronized spindle
operation. Actuator movement control consists of
track-to-track seeks, track following, and correction for both
DC and repeatable AC errors. Motor spin-up and speed
control consists of regulated drive motor current modified
by information derived from the dedicated servo surface.
Synchronized spindle control is derived from an external
sync input that is compared to position information from
the disk surface.
Head Interface
The head interface processes the data signals
transferred between the read/write heads and the data
encoder/decoder. This includes head selection, providing
analog write current to the heads, and amplification and
conversion of impulses from the heads to RLL data.
Actuator Driver
The actuator driver provides the current necessary to
operate the actuator assembly. The driver amplifies the
control information provided by the servo processor, and
outputs the resultant current to the actuator.
Servo Timing
The function of the servo timing circuit is to
~plify
and
convert impulses from the servo head to position and
rotation speed information for the servo processor.
Spindle Motor Driver
The spindle motor driver provides 3-phase current to
start, drive, and control the speed of the in-hub spindle
motor. Hall-effect sensors mounted on the spindle assembly
provide feedback for phase switching control.
DRAFT Product Features 3·15
10/24/90 11:07