Browse Prior Art Database

Method to Confirm Connection of Recording Heads in the Correct Polarity

IP.com Disclosure Number: IPCOM000104588D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Christianson, DJ: AUTHOR [+3]

Abstract

A test method to confirm that a recording head is connected in the correct polarity is disclosed. The head under test can operate in a read mode to detect a magnetic field from a nearby transducer driven by an AC signal. Conversely, the head under test can operate in a write mode, with its field sensed by the transducer. The test compares the electrical phase of the drive signal for one device to that of the signal sensed by the other.

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Method to Confirm Connection of Recording Heads in the Correct Polarity

      A test method to confirm that a recording head is connected in
the correct polarity is disclosed.  The head under test can operate
in a read mode to detect a magnetic field from a nearby transducer
driven by an AC signal.  Conversely, the head under test can operate
in a write mode, with its field sensed by the transducer.  The test
compares the electrical phase of the drive signal for one device to
that of the signal sensed by the other.

Typical signals, shown in Fig. 1, are:

2X CLOCK
          Toggles the drive signal, and defines times at which drive
          and sense phases are compared.
DRIVE SIGNAL
          A digital signal that controls direction of current flow
          through the "writing" device.
SENSED SIGNAL
          Amplified analog signal from the device being operated in a
          "read" mode.
COMPARATOR OUT
          Digital representation of the sensed signal.

These signals are processed by a circuit such as that shown in Fig. 2
as follows:

o   The Exclusive-OR compares the phase of the comparator output and
    the drive signal.
o   The Flip-Flop samples the XOR result at the center of each
    half-cycle.
o   The FF output is displayed to an operator or read by a
    controlling computer.