Method of controlling the position of a write or read head and a device for carrying out the method

Claim 1

A method of detecting the position of a magnetic recording/playback head relative to one of four or more tracks on a record carrier, said tracks containing first information signals and at least four consecutive tracks containing second tracking signals having mutually different frequencies recorded therein in cyclic sequence, said frequencies of said tracking signals being different from frequencies of said information signals, said method comprising the steps of generating a third signal having a frequency which changes from track to track in relation to the frequency of said tracking signals such that, for a given pair of adjacent tracks, the frequency of the third signal associated with one track of said pair differs from the frequency of the tracking signal recorded on the other track of said pair by one of a first and second predetermined number of cycles which are different from each other, subtracting the frequency of said third signal associated with said one track from the frequencies of tracking signals in the tracks adjacent said one track to produce a pair of fourth signals each having a frequency corresponding to said first and second number of cycles, respectively, and obtaining from said pair of fourth signals a resultant signal indicative of displacement of said head from the track being read.

Claim 2

A method of detecting the position of a magnetic recording/playback head relative to one of four or more tracks on a record carrier, said tracks containing first information signals and at least four consecutive tracks containing second tracking signals having mutually different frequencies recorded therein in cyclic sequence, said frequencies of said tracking signals being different from frequencies of said information signals, said method comprising the steps of generating a third signal having a frequency which changes from track to track in relation to the frequency of said tracking signals such that, for a given pair of adjacent tracks, the frequency of the third signal associated with one track of said pair differs from the frequency of the tracking signal recorded on the other track of said pair by one of a first and second predetermined number of cycles which are different from each other, subtracting the frequency of said third signal associated with said one track from the frequencies of tracking signals in the tracks adjacent said one track to produce a pair of fourth signals each having a frequency corresponding to said first and second number of cycles, respectively, and obtaining from said pair of fourth signals a resultant signal indicative of displacement of said head from the track being read.

Claim 5

A device for detecting the position of a recording/playback head capable of simultaneously writing an information signal in one track and reading tracking signals recorded in adjacent tracks and capable of simultaneously reading the information signal in said one track and the tracking signals in adjacent tracks during playback, said device comprising means for generating an output signal with a frequency that changes from track to track in cyclic sequence, means for applying said output signal to the head as a tracking signal when said device is in a recording mode, said tracking signal being recorded in n consecutive tracks as tracking signals of n different frequencies in cyclic sequence, where n is equal to or greater than 4, means for subtracting the frequency of said output signal from the frequencies of the tracking signals read by said head from said adjacent tracks to produce a pair of signals with the respective difference frequencies, means for subtracting the amplitudes of said pair of signals to produce an amplitude difference signal, and means for periodically reversing the polarity of said amplitude difference signal to provide an error signal indicating the position of said recording/playback head.

Claim 6

A device for detecting the position of a recording/playback head capable of simultaneously writing an information signal in one track and reading tracking signals recorded in adjacent tracks and capable of simultaneously reading the information signal in said one track and the tracking signals in adjacent tracks during playback, said device comprising means for generating an output signal with a frequency that changes from track to track in cyclic sequence, means for applying said output signal to the head as a tracking signal when said device is in a recording mode, said tracking signal being recorded in n consecutive tracks as tracking signals of n different frequencies in cyclic sequence, where n is equal to or greater than 4, means for subtracting the frequency of said output signal from the frequencies of the tracking signals read by said head from said adjacent tracks to produce a pair of signals with the respective difference frequencies, means for subtracting the amplitudes of said pair of signals to produce an amplitude difference signal, and means for periodically reversing the polarity of said amplitude difference signal to provide an error signal indicating the position of said recording/playback head.