Apparatus for magnetic tape head alignment

Apparatus for measuring maximum tape head skew in a multiple track magnetic tape recording system by continuously measuring the elapsed time between the occurrence of corresponding peaks of substantially identical output signals read from two tracks of a magnetic recording tape, comparing each measurement so made with the contents of a display register, and placing the larger of the two, in the display register comprising:

• first and second signal processor means for generating signals indicative of the level and signals indicative of the peaks of the output signals read from two tracks of a magnetic recording tape;
• first and second means for selectively connecting said output signals from any one of a plurality of tracks to said first and second signal processor means;
• oscillator means for generating a signal comprising repetitive pulses having a repetition period which is short relative to an allowable misalignment period;
• counter means;
• means for gating said repetitive pulses to said counter means;
• means coordinated with said output signals for clearing said counter means;
• means responsive to said signals from said first and second signal processor means for enabling said gating means during the time between the occurrence of corresponding peaks of said output signals;
• register means;
• means for comparing the contents of said counter means and said register means;
• means for gating the contents of said counter means into said register means if the contents of said counter means is greater than or equal to the contents of said register means;
• and
• means for displaying the contents of said register means.

Apparatus for determining skew in a multiple track magnetic tape recording system by measuring the elapsed time between the occurrence of corresponding peaks of substantially identical alternating output signals read from two tracks of a magnetic recording tape, which peaks occur simultaneously if there is no skew, comprising:

• first and second signal processor means for generating peak indicating signals and threshold indicating signals in response to the output signals read from two tracks of a magnetic recording tape;
• first and second means for selectively connecting said output signals read from any one of a plurality of tracks to said first and second signal processor means respectively;
• oscillator means for generating a repetitive pulse signal having a repetition period which is short relative to an allowable skew period;
• counter means;
• first means for gating said repetitive pulse signal to said counter means;
• means for counting a predetermined number of cycles of said output signals and for generating a signal in response to reaching a count equal to said predetermined number of cycles;
• register means;
• means for displaying the contents of said register means;
• means responsive to said signal generated by said cycle counting means for transferring at least a portion of the contents of said counter means to said register means and subsequently for clearing said counter means and said cycle counter means;
• and
• means responsive to said threshold indicating signals and to said peak indicating signals from said first and second signal processor means for enabling said first gating means during the time between corresponding peaks of said output signals.

The method of measuring read head skew in a multiple track magnetic tape recording system comprising repetitive performance of the following steps:

• a. reading two tracks of a standard alignment tape having prerecorded synchronous signals on at least two tracks thereof;
• b. generating signals indicative of the peaks of corresponding portions of said prerecorded synchronous signals read from said two tracks;
• c. generating an enable signal in response to the first to arrive of said peak indicative signals;
• d. generating a disable signal in response to the later to arrive of said peak indicative signals;
• e. counting pulses from a high frequency pulse source during the time period between the occurrence of said enable signal and said disable signal;
• f. transferring the count obtained from step (e) to a register circuit;
• and
• g. displaying the contents of said register circuit.

The method of measuring read head skew in a multiple track magnetic tape recording system comprising the following steps:

• a. reading two tracks of a standard alignment tape having prerecorded synchronous signals on at least two tracks thereof;
• b. generating signals indicative of the peaks of corresponding portions of said prerecorded synchronous signals;
• c. processing said peak indicative signals into an enable signal corresponding to the first to arrive of said peaks and a disable signal corresponding to the later to arrive of said peaks;
• d. generating a sequence of high frequency pulses;
• e. counting said high frequency pulses during the time between said enable signal and said disable signal;
• f. accumulating a count over a predetermined number of said peaks;
• g. averaging said count over said predetermined number of said peaks;
• h. transferring an average count to a register;
• i. clearing the accumulated count;
• and
• j. displaying the contents of said register.

The method of measuring the write head alignment of a multiple track magnetic tape recording system comprising the following steps:

• a. aligning a read head of the recording system;
• b. writing a periodic signal onto at least two tracks of a magnetic recording tape;
• c. reading said periodic signal with said read head;
• d. generating signals indicative of the peaks of said periodic signal so read;
• e. generating enable signals corresponding to the first to arrive of said peaks and disable signals corresponding to the later to arrive of said peaks in response to said peak indicative signals;
• f. counting pulses from a high frequency pulse source during the time between said enable signals and said disable signals;
• g. accumulating a count over a predetermined number of said peaks;
• h. averaging said count over said predetermined number of said peaks;
• i. transferring an average count to a register circuit;
• j. clearing the accumulated count;
• and
• k. displaying the contents of said register circuit.

The method of measuring maximum tape head skew in a multiple track magnetic tape recording system comprising the following steps:

• a. reading recorded signals from two tracks of a magnetic tape;
• b. generating signals indicative of the peaks of corresponding portions of said recorded signals;
• c. processing said peak indicative signals into an enable signal corresponding to the first to arrive of said peaks and a disable signal corresponding to the later to arrive of said peaks;
• d. counting pulses from a high frequency pulse source during the time period between the occurrence of said enable signal and said disable signal;
• e. comparing a count with the contents of a register circuit;
• f. transferring said count into said register circuit if said count is greater than or equal to the contents of said register circuit;
• g. clearing said count after the comparing and transferring steps are accomplished;
• h. clearing said register circuit periodically after a predetermined number of counting time periods;
• and
• i. displaying the contents of said register circuit.