Rotary head type magnetic recording and reproducing apparatus and method of producing tracking control signals therefor

A method of producing a tracking control signal in a rotary head type magnetic recording and reproducing apparatus having a plurality of rotary heads arranged for scanning parallel, oblique tracks of a magnetic tape for signal recording and reproduction with a predetermined displacement distance between the track scanning start ends of two adjacent tracks as measured in a direction perpendicular to the longitudinal direction of the tracks, the method comprising the steps of:

• recording a first record position detecting signal and a first tracking signal on a first portion and a second portion, respectively, of a series of first tracks, said first tracks being predetermined ones of said parallel, oblique tracks which are spaced from one another, said first record position detecting signal and said first tracking signal having frequencies different from each other, said first and second portions of said first tracks being at different locations so as to not overlap each other, and recording a second record position detecting signal and a second tracking signal on a first portion and a second portion, respectively, of a series of second tracks, said second tracks being other predetermined ones of said parallel, oblique tracks which are spaced from one another so as to be interleaved with said first tracks so that said first tracks are adjacent to said second tracks, said second record position detecting signal and said second tracking signal having frequencies different from each other, said first and second portions of said second tracks being at different locations so as to not overlap each other, wherein at least parts of the first portions of two tracks of one of said first and second tracks which are adjacent to any one of the other of said second and first tracks do not overlap with each other as viewed in said direction perpendicular to the track longitudinal direction, at least parts of the second portions of the two tracks of one of said first and second tracks which are adjacent to any one of the other of said second and first tracks do not overlap with each other as viewed in said direction perpendicular to the track longitudinal direction, at least a part of the first portion one of any one of said first and second tracks on which first portion one of said first and second record position detecting signals is recorded is not farther from the track scanning start ends than one of the non-overlapping parts of the second portions of two adjacent tracks which non-overlapping part is nearer to the track scanning start ends as viewed in said direction perpendicular to the track longitudinal direction, one of said first and second tracking signals being recorded on said second portions;
• scanning said first tracks to reproduce the recorded first record position detecting signal and to reproduce first and second crosstalk signals of the recorded second tracking signal from the two adjacent second tracks, and scanning said second tracks to reproduce the recorded second record position detecting signal and to reproduce third and fourth crosstalk signals of the recorded first tracking signal signal from the two adjacent first tracks;
• and
• detecting the difference of the levels between said first and second crosstalk signals with first timing based upon the reproduction of the recorded first record position detecting signal from said first tracks to generate a first tracking error signal, and detecting the difference of the levels between said third and fourth crosstalk signals with second timing based upon the reproduction of the recorded second record position detecting signal from said second tracks to generate a second tracking error signal, said first and second tracking error signals being alternately used for said first and second tracks to constitute said tracking control signal.

A rotary head type magnetic recording and reproducing apparatus comprising:

• a plurality of rotary heads mounted on rotary head carrying means and arranged for scanning parallel, oblique tracks of a magnetic tape for signal recording and reproduction with a predetermined displacement distance between the track scanning start ends of two adjacent tracks as measured in a direction perpendicular to the longitudinal direction of the tracks;
• means for driving said head carrying means;
• means for driving said magnetic tape;
• means for processing signals to be supplied to and from said head so that said signals are properly recorded on and reproduced from the tracks of said tape;
• means for generating a head position signal in synchronism with rotation of said rotary heads, said head position signal containing a plurality of scanning start pulses each representative of the time point when one of said head is located at the scanning start end of said tracks;
• signal source means capable of generating at least two different frequencies;
• means connected with said head position signal generating means for generating two first gate pulse signals starting, respectively, upon elapse of first and second time periods from scanning start pulses for each of a series of first tracks and second tracks, said first tracks being predetermined ones of said parallel, oblique tracks spaced from one another, said second tracks being other predetermined ones of said parallel, oblique track spaced from one another so as to be interleaved with said first tracks so that said first tracks are adjacent said second tracks;
• means connected with said first gate pulse signal generating means for generating a second gate pulse signal for said first tracks in a first timed relation with the associated one of said first gate pulse signals and for generating a third gate pulse signal for said second tracks in a second timed relation with the other one of said first gate pulse signals under control of said head position signal received from said head position signal generating means;
• selection means connected with said signal source means and with said first gate pulse signal generating means and said second and third gate pulse signal generating means to deliver first and second signals having first and second ones of said different frequencies of said signal source means during the width of said first gate pulse signals as first and second record position detecting signals, a third signal having a third one of said different frequencies during the width of said second gate pulse signal as a first tracking signal and a fourth signal having one of said different frequencies and being different from said first and second frequencies during the width of said gate pulse signal as a second tracking signal, said signal processing means being arranged to receive the output of said selection means for recording of said first record position detecting signal and said first tracking signal on said first tracks, and said second record position detecting signal and said second tracking signal on said second tracks of said magnetic tape through said magnetic heads and to receive from said heads and process reproduced signals containing information signals, record position detecting signals, tracking signals and crosstalk signals of the tracking signals;
• and
• tracking control circuit means interconnected between said signal processing means and either one of said magnetic tape drive means and said head carrying means drive means, said tracking control circuit means including
• (a) means connected with said signal processing means for extracting reproduced first and second record position detecting signals for the tracks from the processed reproduction output of said signal processing means,
• (b) means connected with said signal processing means for alternately producing first and second crosstalk detection signals from said second tracks and third and fourth crosstalk detection signals from first tracks on the basis of the crosstalks contained in the processed reproduction output of said signal processing means,
• (c) means connected with said reproduced first and second record position detecting signal extracting means for generating a sampling signal on the basis of said reproduced first and second record position detecting signals, and
• (d) means for alternately comparing said first and second crosstalk detection signals and said third and fourth crosstalk detection signals by the use of said sampling signal to produce a tracking control signal to be fed to either one of said drive means.