US 4,038,692 A · Tape sensing device for magnetic tape recording and/or reproducing apparatus

Abstract

A device for sensing the type of magnetic coating on a magnetic tape while the latter is at rest, for example, in a magnetic tape recording and/or reproducing apparatus, has a DC magnetic recording head energizable by a predetermined DC voltage for applying a DC magnetic flux to the tape with which such head is engaged, a magnetic sensing element preferably coupled with the DC magnetic recording head for sensing the remanence or residual magnetism in the tape while the latter remains at rest following the application of the DC magnetic flux to the tape, and a level detector for detecting the level of the sensed remanence of the tape as an indication of the type of magnetic coating thereon. Such level detector may be advantageously employed for controlling a frequency equalizing circuit and/or a bias oscillator included in the signal recording circuit of the recording and/or reproducing apparatus so as to automatically adapt the latter for recording operations on the particular type of tape installed therein.

Claims16

Dependent claims

A device for sensing the type of magnetic coating on a magnetic tape, comprising a DC magnetic recording head adapted to engage the magnetic tape, means for applying a predetermined DC voltage to said head so that the latter applies a DC magnetic flux to the tape while said tape is at rest, means for discontinuing the application of said DC magnetic flux, means for sensing the remanance of the magnetic tape while the latter remains at rest following the discontinuance of said DC magnetic flux to the tape, and level detecting means for detecting the level of the sensed remanence of the tape as an indication of the type of magnetic coating thereon.

A magnetic tape recording and/or reproducing apparatus:

comprising a signal recording circuit for recording informational signals on a magnetic tape;
a frequency equalizing circuit connected with said signal recording circuit and having a variable equalizing function for adapting the signal recording circuit to use with magnetic tapes having different types of magnetic coatings thereon;
a device for sensing the type of magnetic coating on a magnetic tape installed in the apparatus including a DC magnetic recording head adapted to engage the magnetic tape, means for applying a predetermined DC voltage to said head so that the latter applies a DC magnetic flux to the tape while said tape is at rest, means for discontinuing the application of said DC magnetic flux to said tape, means for sensing the remanence of the magnetic tape while the latter remains at rest following the discontinuance of said DC magnetic flux to the tape, and level detecting means for detecting the level of the sensed remanence of the tape as an indication of the type of magnetic coating thereon;
and means responsive to the detected level of the sensed remanence for controlling said variable equalizing function of the frequency equalizing circuit in accordance with the type of magnetic coating on the tape installed in the apparatus.

1 more element

A magnetic tape recording and/or reproducing apparatus comprising a signal recording circuit for recording informational signals on a magnetic tape;

a frequency equalizing circuit connected with said signal recording circuit and having a variable equalizing function for adapting the signal recording circuit to use with magnetic tapes having different types of magnetic coatings thereon;
a device for sensing the type of magnetic coating on a magnetic tape installed in the apparatus including a DC magnetic recording head adapted to engage the magnetic tape, means for applying a predetermined DC voltage to said head so that the latter applies a DC magnetic flux to the tape while said tape is at rest, means for sensing the remanence of the magnetic tape while the latter remains at rest following the application of said DC magnetic flux to the tape, said means for sensing the remanence of the magnetic tape including a magnetoelectric transducer coupled with said magnetic recording head, and level detecting means for detecting the level of the sensed remanence of the tape as an indication of the type of magnetic coating thereon;
and means responsive to the detected level of the sensed remanence for controlling said variable equalizing function of the frequency equalizing circuit in accordance with the type of magnetic coating on the tape installed in the apparatus.

Dependencies are inferred from the claim text.

Tape sensing device for magnetic tape recording and/or reproducing apparatus

Life of this patent

Tape sensing device for magnetic tape recording and/or reproducing apparatus

Life of this patent

Abstract

Claims16