CN1071042C - Method and device for measuring relative height of magnetic head of magnetic recording device - Google Patents
Method and device for measuring relative height of magnetic head of magnetic recording device Download PDFInfo
- Publication number
- CN1071042C CN1071042C CN96109602A CN96109602A CN1071042C CN 1071042 C CN1071042 C CN 1071042C CN 96109602 A CN96109602 A CN 96109602A CN 96109602 A CN96109602 A CN 96109602A CN 1071042 C CN1071042 C CN 1071042C
- Authority
- CN
- China
- Prior art keywords
- magnetic head
- magnetic
- signal
- pilot signal
- tape
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
Abstract
本发明公开一种磁记录装置的磁头相对高度及走带速度的测量方法及其装置，其是把在一般录音的走带速度下记录了信号的磁带，在不同于一般录音的走带速度的大致一定的走带速度下放音，从磁头检测出磁道偏离信号，通过比较从多个磁头得到的磁道偏离信号的相位，检测出多个磁头间的相对高度。另外，本发明的测定装置由磁道偏离信号的波长检测出走带速度偏差。
The present invention discloses a method and apparatus for measuring the relative height of magnetic heads and tape speed in a magnetic recording device. The method involves playing back a tape recorded at a normal recording speed at a substantially constant speed different from the normal recording speed. Track deviation signals are detected from the magnetic heads, and the relative heights of the multiple magnetic heads are determined by comparing the phases of the track deviation signals obtained from the multiple heads. Furthermore, the measuring apparatus of the present invention detects tape speed deviations based on the wavelengths of the track deviation signals.
Description
The invention relates to the measuring method and the device thereof of the magnetic head relative height of measuring magnetic recording system.
Helical scan such as VTR or DAT type magnetic recording system because its multifunction and high density recordingization are compared with general magnetic recording system, requires to have the machining precision and the controllability of height.Therefore, to the measurement of each parameter of helical scan type magnetic recording system, must be tighter than the measurement of each parameter of general magnetic recording system.
In this measurement, to being recorded in the measurement of the signal amplitude (width of magnetic track) on the tape, be an important measurement project, when it is the signal of regenerative recording on tape, for the level that determines regenerated signal necessary.
In nearest helical scan type magnetic recording system, be by be installed on the rotor a plurality of magnetic heads alternatively scanning tape (as shown in Figure 8) come picture intelligence with (or) voice signal records on the tape.The width of magnetic track is decided by the position and the tape running speed of the magnetic head installed on the rotor.
Measuring method to head position describes below.
As shown in Figure 9, wherein, H represents the magnetic height, R represents lead-in wire, and magnetic head 2a and magnetic head 2b correctly are installed on the original due height by the turning axle direction of the rotor of being made up of last cylinder C1 and following cylinder C2 1, tape running speed one regularly scans track width and fixes.If tape running speed is certain, and the setting height(from bottom) of magnetic head will produce the error of track width when having error with respect to the turning axle direction X of rotor, and existence is the problem of regenerated signal well.The relative height of magnetic head is to be defined by the absolute altitude from certain reference field (omitting the figure) to certain magnetic head and above-mentioned certain reference field difference to the absolute altitude of other magnetic heads.Specifically be exactly, the relative height of magnetic head, be by the absolute altitude from reference point 31 to magnetic head 2a when the pre-determined line of being centered close to of magnetic head 2a 30 positions, the difference of the absolute altitude from reference point 31 to magnetic head 2b when making the pre-determined line of being centered close to of magnetic head 2b 30 positions with the rotor rotation defines.Reference point 31 is positioned on line 30 positions.Reference point 31 also can be selected on the plane, chassis (base) of magnetic recording system (omitting among the figure).
The measurement of magnetic head relative height, method of adjustment are being studied by people always.For example open in the flat 4-252414 communique, just put down in writing the measurement/method of adjustment of relevant magnetic recording system the spy.Opening the method for being put down in writing in the flat 4-252414 communique the spy is, with rotation in the synchronous flash illumination of rotation axial plane, utilize fixed camera to take and forward camera magnetic head nearby to, measure the height of each magnetic head respectively.According to the error of its magnetic head height, correspondingly use the laser radiation head base, adjust the magnetic head height by making the head base drawdown deformation.
But, during this present magnetic head relative height error is adjusted, must utilize directly definite head positions such as microscope, and use the laser radiation magnetic head.Therefore, be installed to rotor individually in the special measurement mechanism and go.After adjusting the magnetic head relative height on the rotor monomer, when rotor being installed on the chassis of magnetic recording system, the mounting plane of rotor crooked causes the misalignment of magnetic head relative height sometimes.To measure the magnetic head relative height under the state on the chassis be necessary so be installed at rotor.
Of the present inventionly present be, be installed at rotor under the state on chassis, detect the relative height between a plurality of magnetic heads.
In order to achieve the above object, the present invention is by the following technical solutions:
A kind of measuring method of magnetic head relative height, it is the relative height that is used to measure described relatively first magnetic head of second magnetic head of magnetic recording system, described magnetic recording system comprises: under first tape running speed, record first and second pilot signal on the tape, with first magnetic head of the second tape running speed playback different with described first tape running speed; And under described first tape running speed, record described first and second pilot signal on the described tape, with second magnetic head of the described second tape running speed playback, described measuring method is characterized in that, comprising:
According to first and second pilot signal of the described first magnetic head playback, first generative process of first signal of the time-varying relationship of the difference of generation expression first pilot signal and second pilot signal;
According to first and second pilot signal of the described second magnetic head playback, second generative process of the secondary signal of the time-varying relationship of the difference of generation expression first pilot signal and second pilot signal;
Detect first testing process of the phase place of described first signal;
Detect second testing process of the phase place of described secondary signal; And
Obtain poor between the phase place of described first signal and the secondary signal phase place,, calculate the process of described second magnetic head with respect to the relative height of described first magnetic head according to difference.
The measuring method of described magnetic head relative height is characterized in that:
Above-mentioned tape have first magnetic track, second magnetic track and be clipped in first magnetic track and second magnetic track between the 3rd magnetic track, above-mentioned first pilot signal of record in described first magnetic track, above-mentioned second pilot signal of record in described second magnetic track, recording level is 0 pilot signal in described the 3rd magnetic track.
A kind of measurement mechanism of magnetic head relative height, it is used to measure the relative height of second magnetic head of magnetic recording system with respect to described first magnetic head, described magnetic recording system has: will under first tape running speed, record first and second pilot signal on the tape, with first magnetic head of the described first tape running speed second tape running speed playback inequality; And will under described first tape running speed, record described first and second pilot signal on the described tape, with second magnetic head of the described second tape running speed playback, described measurement mechanism is characterised in that and comprises:
According to described first and second pilot signal by the described first magnetic head playback, first generating unit of first signal of the time-varying relationship of the difference of generation described first pilot signal of expression and second pilot signal;
According to described first and second pilot signal, generate second generating unit of secondary signal of time-varying relationship of the difference of described expression first pilot signal and second pilot signal by the described second magnetic head playback;
Detect first test section of the phase place of described first signal;
Detect second test section of the phase place of described secondary signal; And
Obtain poor between the phase place of the phase place of described first signal and secondary signal,, calculate the calculating part of described the 2nd magnetic head with respect to the relative height of described first magnetic head according to described difference.
The measurement mechanism of described magnetic head relative height is characterized in that:
Above-mentioned tape have first magnetic track, second magnetic track and be clipped in first magnetic track and second magnetic track between the 3rd magnetic track, in described first magnetic track, record above-mentioned first pilot signal, in described second magnetic track, record above-mentioned second pilot signal, in described the 3rd magnetic track, record level and be 0 pilot signal.
The present invention has following positive effect:
As mentioned above, according at general record with monitor signal level difference and time relation when being different from regeneration tape under the tape running speed of general record, can obtain the relative height error between a plurality of magnetic heads.Therefore, can be installed in state on the chassis, promptly in fact finish under the state of assembling of tested device, measure magnetic head relative height error at rotation bolt face.So, can obtain comprising because rotor is installed to the caused error of installation process on the chassis, the relative height error between a plurality of magnetic heads.
Following with reference to accompanying drawing, describe embodiments of the invention in detail:
Fig. 1 is the oblique view of major part of the recording/reproducing of the relevant magnetic recording system of expression.
Fig. 2 is the mode chart of the relative position relation of expression magnetic track and magnetic head.
Fig. 3 represents the example that measurement mechanism of the present invention constitutes.
Fig. 4 is the processing flow chart of expression CPU7 shown in Figure 3.
Fig. 5 (a) is that expression will be stored in the memory 6, the waveform 301 that the related data of magnetic head (a) was described with uniformly-spaced (sample time), Fig. 5 (b) is that expression will be stored in the memory 6, the waveform 303 that the related data of magnetic head (b) was described with uniformly-spaced (above-mentioned sample time), Fig. 5 (c) be expression will be stored in the storer data by threshold value O (v) (above-mentioned sample time) waveform 302 of describing uniformly-spaced after the binarization, Fig. 5 (d) expression be stored in data in the memory by threshold value O (V) digitizing after (above-mentioned sample time) waveform 304 of describing uniformly-spaced.
When Fig. 6 is expression general record speed and the certain speed that the is different from general record speed planimetric map of the position relation of the magnetic head 2a during regeneration and magnetic head 2b down.
Fig. 7 is the oscillogram that expression is stored in the related data of the ATF error signal waveform in the memory.
Fig. 8 is the figure that expression is recorded in the signal magnetic track on the tape.
Fig. 9 is the figure of expression magnetic head relative height and magnetic head height.
Fig. 1 is that the device that the present invention will measure is the oblique view of the relevant major part of recording/reproducing of magnetic recording system.
Below, magnetic recording system is done simple explanation.
Rotor 1 has magnetic head 2a, the 2b of the signal of regenerative recording on tape 20.Rotor 1 is along the direction rotation of arrow A.Tape 20 is clipped between capstan 21 and the tightening pulley 22, and along with the rotation of capstan 21, tape 20 is along arrow B direction tape transport.The tape transport of tape 20 is subjected to the guiding of bar 23.
The recording/reproducing of signal is alternatively to scan the tape 20 of crossing on the rotor 1 of rotation by magnetic head 2a, 2b to realize.Magnetic head 2a, 2b are fixed on the rotor 1 by fixed screw 19a, 19b.
Fig. 8 is an example that is recorded in the signal on the tape 20.As shown in Figure 8, signal is recorded on the tape 20 oblique a plurality of magnetic tracks 24 that are divided into.Fig. 2 is the relative position relation mode chart of expression magnetic track 25a-25e and magnetic head 26a-26c.Magnetic track 25a-25e among Fig. 2 is the 24 vertical result displayed of the magnetic track among the figure.As can be seen from Figure 2, the scanning position of magnetic head 26a-26c has nothing in common with each other.Arrow is the expression direction of scanning.
Below by Fig. 9 the tape running control that utilizes ATF (Auto Track Fouowing) is described.
In magnetic track 25a-25e, except that general signal, also having write down frequency is the pilot signal of f1, f0, f2, f0, f1.The picture intelligence that general signal is meant and (or) voice signal.In general, the frequency of the general signal of frequency ratio of pilot signal is low, but the frequency of pilot signal also can be than the frequency height of general signal.
The order of recorded pilot signal is the order of magnetic track 25a～25e as shown in Figure 2.Order corresponding to the frequency of each pilot signal is f1 → f0 → f2 → f0 → f1 in addition.Corresponding to the signal under the whole magnetic recording is that frequency is by f1 → f0 → f2 sequential loop pilot signal repeatedly.In addition, frequency is that the level of the pilot signal of f0 also can be 0.In order to simplify explanation, below in the explanation, suppose that frequency is that the level of the pilot signal of f0 is 0 to ATF.
The following describes be head scanning magnetic track 25b the time example.Because the width of magnetic head 26a～26c is wideer than track width 25b, so in the signal of magnetic head 26a regeneration, also comprised and be recorded in adjacent magnetic track 25a and the pilot signal among the 25c.Specifically, frequency is the pilot signal of f1, f2, is included among the signal of regeneration.
Because the center of magnetic head 26a almost overlaps with the center of magnetic track 25b, be identical so magnetic head 26a and the frequency that obtains are the level of the pilot signal of f1, f2.But, when magnetic head 26b scanning magnetic track 25b, frequency is that the level of the pilot signal of f2 will be the level of the pilot signal of f1 greater than frequency.Otherwise when magnetic head 26c scanning magnetic track 25b, frequency is that the level of the pilot signal of f1 will be the level of the pilot signal of f2 greater than frequency.Like this, with respect to the central authorities of magnetic track, when the scanning position of magnetic head was partial to a certain side, the level of the pilot signal on its direction on the adjacent magnetic track just changed.
In ATF control, be from record the signal of magnetic track regeneration of pilot signal that frequency is f0, detect the signal that frequency is f1, f2, deduct " pilot signal level that frequency is f1 " from " frequency is the pilot signal level of f2 " and draw the ATF error signal, in order to make this signal approach 0 as much as possible, the capstan revolution is controlled, track center and magnetic head center are consistent.
Utilize Fig. 3 that the formation of the measurement mechanism of magnetic recording system of the present invention is described below.Fig. 3 is the pie graph of the measurement mechanism of magnetic recording system of the present invention.The measurement mechanism of Fig. 3 has ATF error signal generative circuit 3a, 3b and control circuit 4.
With first and second pilot signal that records under first tape running speed on the tape,, receive respectively by ATF error signal generative circuit 3a, 3b being different from the pilot signal that forms by magnetic head 2a, 2b regeneration under second tape running speed of first tape running speed.Magnetic head 2a and magnetic head 2b are installed on the rotor 1, and the turning axle of magnetic head 2a, rotor and magnetic head 2b constitute 180 degree angles.In addition, represented magnetic head 2a, 2b is state from the rotor upper perspective among Fig. 3.
ATF error signal generative circuit 3a, 3b generate the ATF error signal on the basis of the pilot signal that receives.In addition, between magnetic head 2a, 2b and ATF error signal generative circuit, also be provided with the testing circuit that the signal that magnetic head 2a, 2b are regenerated carries out the prime amplifier of amplification and detect pilot signal from the signal of magnetic head 2a, 2b regeneration.
In control circuit 4, have: with the ATF error signal of exporting among ATF error signal generative circuit 3a, the 3b simulate a digital conversion (be referred to as later on A/D conversion) A/D change-over circuit 5, store the ATF error signal carried out the memory 6 of A/D conversion back gained data and carried out the CPU7 of calculation process to being stored in data in the memory.The result of CPU7 calculation process is presented on the monitor.
Utilize Fig. 4 and Fig. 5 that simple explanation is carried out in the action of the measurement mechanism of magnetic recording system of the present invention below.Fig. 4 is the processing flow chart of the processing that CPU7 carried out in the presentation graphs 3.
Handling in 9 in binarization, is the data that will be undertaken by A/D change-over circuit 5 after the A/D conversion, i.e. the quantized signal of discretize, and threshold value is according to the rules carried out binarization.In other words, just the process of the ATF error signal binarization of the pilot signal generation of regenerating according to magnetic head 2a, 2b.Specifically, the quantized signal greater than certain threshold value is transformed into 1, and the quantized signal less than certain threshold value is transformed into-1.The ATF error signal is carried out A/D conversion, carried out the example of the signal that 2 o'clock inhibition and generation handles and be illustrated among Fig. 5 (c) and Fig. 5 (d) being stored in data in the memory 6.Among Fig. 5 (c) and Fig. 5 (d), abscissa express time t, ordinate represent 2 system signal values.
With zero crossing determination processing 10, in the data that binarization is handled, the positive and negative counter-rotating of data is judged constantly.For example, in Fig. 5 (c) institute example, detect a1, a2, a3 and a4 constantly, in Fig. 5 (d) institute example, detected b1, b2 and b3 constantly.
Wavelength detect to handle 11, according to zero crossing constantly, i.e. binarization positive and negative counter-rotating moment of data, detect wavelength.For example, in Fig. 5 (c) institute example, deduct a1 constantly, can obtain the wavelength of the relevant ATF error signal of magnetic head 2a from moment a3.In Fig. 5 (d) institute example, deduct b1 constantly from moment b3, can obtain the wavelength of the relevant ATF error signal of magnetic head 2b.
Phase-detection handles 12, is that the zero crossing evolution becomes phase value on the time shaft that will obtain according to the zero crossing judgment processing.The associated phase value of the signal that can obtain the associated phase value of the signal that obtains from magnetic head 2a thus and obtain from magnetic head 2b.
Phase difference detection handles 13, is associated phase value poor of the associated phase value of obtaining the signal that obtains from magnetic head 2a and the signal that obtains from magnetic head 2b.
Magnetic head relative height error detection process 14 is phase difference detection to be handled 13 phase difference values that draw be transformed into the magnetic head relative height, by relatively this transformed value and theoretical value, detects magnetic head relative height error.
The tape running speed deviation detects handles 15, is after wavelength detection processing 11 wavelength conversions that obtain are become tape running speed, to get tape running speed and theoretical value by comparing conversion, obtains the tape running speed deviation.
Action to measurement mechanism of the present invention is elaborated below.
As shown in Figure 1, under the state that the revolution of capstan 21 is set at the w% of revolution when being higher than general record, make tape 20 with the certain speed tape transport.Under regeneration mode, magnetic head 2a, the signal of 2b regenerative recording on tape 20.For example, the revolution when considering with respect to general record, the revolution during regeneration exceeds 1% situation.The revolution of capstan is 180rpm when supposing general record, and the revolution when then regenerating is 181.8rpm.And, only detect the ATF error signal and do not carry out above-mentioned ATF control.And the regeneration tape 20 that uses is track width and prescribed form is very approaching, magnetic track is crooked seldom, be known as the tape that is used to adjust tape transport of standard reference tape preferably.
Utilize Fig. 6 that the magnetic track and the relation of the position between magnetic head 2a, the 2b of tape 20 are described below.
In Fig. 6, magnetic track 16a～16i totally 9 tracks have been expressed.In magnetic track 16a～16i, record the monitor signal that frequency is one of f0～f2 respectively.Specifically, record the pilot signal that frequency is f1 among the magnetic track 16a, record the pilot signal that frequency is f0 among the magnetic track 16b, record the pilot signal that frequency is f2 among the magnetic track 16c.(frequency is arranged is that pilot signal, the frequency of f1 is that f0 pilot signal and frequency are the pilot signal of f2 in journal among the magnetic track 16d～16i) at the later magnetic track of magnetic track 16c.
At first, magnetic head 2a is positioned at position 17a, and the center of magnetic track 16a is consistent with the center of magnetic head 2a.After magnetic head 2a has scanned magnetic track 16a, magnetic head 2b scanning magnetic track 16b.Because regenerative recording than the speed (writing speed) of tracer signal toward tape on w% soon, makes the center of magnetic head 2b in the speed (reproduction speed) of the signal on the tape, the edge is scanned from the position that the misalignment of magnetic track 16b goes out the track width of w%.Afterwards, magnetic head 2a scanning magnetic track 16c, magnetic head 2b scans 16d.
Like this, when with respect to track pitch L, during the big w% of sweep span S, the deviation of scanning position will increase pro rata along with the increase of scanning times.
Yet, because being poor (F2-F1) by the level of pilot signal, the error signal of ATF decides, for example, should work as the magnetic head at scanning magnetic track 16b center, even deviation arrives the center of magnetic track 16f, ATF error signal (F2-F1) is similarly 0.And F1 represents that frequency is the level of the pilot signal of f1, and F2 represents that frequency is the level of the pilot signal of f2.
Therefore, when the deviation of head position reached 4 track widths, the ATF error signal will be restored.If be conceived to the single magnetic head in 2 magnetic heads, the cyclical signal that it is one-period that the ATF error signal becomes with 4 track widths.
In addition, as shown in Figure 7, wherein, horizontal ordinate express time t, vertical emblem is represented ATF error signal (f2-f1), because scanning position 17a and the 17b of magnetic head 2a and 2b have almost departed from 1 track width, if magnetic head 2b is provided with correctly with respect to the relative height of magnetic head 2a, the ATF error signal will be offset the almost part of a track width, the i.e. phase place of the quater-wave section of the period of change of ATF error signal.
Below, the relation that is stored between the data in the memory 6 among the ATF error signal that the ATF error signal generative circuit 3a among Fig. 3 and 3b are generated and Fig. 3 is carried out simple explanation.
As shown in Figure 1, magnetic head 2a and magnetic head 2b alternatively scan the tape 20 on the rotor 1.Therefore, the signal waveform from ATF error signal generative circuit 3a and 3b output is discontinuous signal waveform.The ATF error signal of ATF signal generating circuit 3a and 3b output is carried out the A/D conversion by A/D change-over circuit 5.The data storage of the ATF error signal after the expression A/D conversion is in memory 6.But when ATF error signal generative circuit 3a did not generate the ATF error signal, the related data of magnetic head 2a just was not stored among the memory 6.And when ATF error signal generative circuit 3b did not generate AT F error signal, the related data of magnetic head 2b was not stored among the memory 6 yet.If therefore the data of storing in the memory 6 equally spaced (sample time of above-mentioned A/D change-over circuit use) show, the waveform of ATF error signal just becomes waveform shown in Figure 7.
As a reference, the related data that is stored in the magnetic head 2 (a) in the memory 6 is illustrated among Fig. 5 (a) with the waveform 301 that draws uniformly-spaced (above-mentioned sample time), the related data that is stored in the magnetic head (b) in the memory 6 is illustrated among Fig. 5 (b) with uniformly-spaced (above-mentioned sample time) waveform 303 that draws.In Fig. 5 (a) and Fig. 5 (b), horizontal ordinate express time t, ordinate is represented the ATF error signal level.
For the data that are stored in the memory 6, carry out two inhibition and generation and handle 9.Binarization is handled, be meant according to central value as the set magnitude of voltage or the peak-to-peak value (p-p value) of threshold value, data conversion become 1 with the processing of-1 two value.When data during greater than threshold value, be transformed into 1, when data during, be transformed into-1 less than threshold value.
As a reference, according to threshold value 0 (v) will be stored in data binarization in the memory value be illustrated among Fig. 5 (c) with the waveform 302 that draws uniformly-spaced (above-mentioned sample time), (value that v) will be stored in after the data binarization in the memory is illustrated among Fig. 5 (d) with the waveform 304 that draws uniformly-spaced (above-mentioned sample time) according to threshold value 0.
Handle in 10 at zero fork shown in Figure 4, detect the positive and negative counter-rotating moment of binarization signal.Zero crossing constantly, the change point of the difference value by detecting binary signal can obtain.For example, as the zero crossing of the relevant ATF error signal of magnetic head 2a constantly, can be in the hope of the moment a1 among Fig. 5 (a), moment a2, moment a3 and moment a4, as the zero crossing of the relevant ATF error signal of magnetic head 2b constantly, can be in the hope of the moment b1 among Fig. 5 (b), b2, b3 and b4 constantly constantly constantly.
Detect in the processing 11 at wavelength shown in Figure 4, wavelength is equivalent to 2 times zero crossing moment spacing.Therefore, in Fig. 5, a1 is to the time of a3 is equivalent to a wavelength X constantly constantly.Thereby by:
λ (sec)=a3-a1 ... (1) calculates.Certainly, wavelength X also can wait by a4-a2, b3-b1 and calculate.
Handle in 12 in phase-detection shown in Figure 4, the phase value of a1～moment an is respectively α 1～α n if establish constantly, then passes through
α i (rad)=(ai-a1) * 2 π/λ (i=1～n) ... (2) calculate.
Similarly, be that benchmark calculates the phase value of b1～moment bn constantly with moment a1.If constantly the phase value of b1～moment bn is respectively β 1～β n, then pass through β i (rad)=(bi-a1) * 2 π/λ (i=1～n) ... (3) calculate.
Like this, utilize the phase value that obtains, just can carry out phase difference detection and handle 13.If phase differential is θ i, then by formula (2), formula (3), by
θ i=β i-α i (i=1～n) ... (4) calculate.
Then, utilize the phase differential that obtains according to formula (4), carry out magnetic head relative height error detection process 14.
At first, phase difference error δ i is tried to achieve by following formula.
δi=θi-λ/4 (i=1～n)…………(5)
When the relative height of magnetic head did not have error, because phase differential θ i is the wide part of a tracks, i.e. λ/4 were so phase difference error δ i is 0.Therefore, phase difference error δ i, the caused phase deviation of relative height error of expression magnetic head 2a and magnetic head 2b.Like this, for phase difference error δ i is transformed into magnetic head relative height error, carry out following processing.
The scanning position deviation of 4 times of track widths is the phase place of 2 π corresponding to a wavelength.Therefore, establishing track width is Tw (μ m), and then 4 * Tw is corresponding to 2 π.Phase difference error δ i can be transformed into magnetic head relative height error Xi (μ m) by following formula.Xi=4×Tw×δi/2π (i=1～n) (6)
,, also need not calculate a lot of here, only calculate one and also be fine though can obtain n Xi.And, in order to reduce to detect error, also can obtain the mean value of magnetic head relative height error Xi.
Like this, just can the magnetic head relative height error numerical value that CPU7 among Fig. 3 calculates be presented on the monitor 8.
Below the velocity deviation among Fig. 4 being detected processing 15 describes.
When the capstan revolution was accelerated the tape running speed of W%, as mentioned above, head scanning can be widened W% than track width at interval.If tape running speed is correctly accelerated W%, every scanning 100/w (returning), scanning position can track width of deviation.A period of change that produces the ATF error signal is the scanning position deviation of 4 times of track widths, needs scanning 400/w time.Here suppose that the time that single pass needs is T (sec).
For example, revolution is 9000rpm, and when two magnetic heads became 180 degree relative, T that single pass is taken time (sec) was T=0.5 * 60/9000.Thereby a wavelength that produces the ATF error signal is that the scanning deviation required time Y (sec) of 4 times of track widths is:
Y=T×400/W (7)
If tape is by set speed running, the wavelength of Fig. 4 detects and handles 11 wavelength X that drawn (sec) is consistent with Y.But, even the capstan revolution is set for than the correctly fast W% of benchmark revolution, because factors such as leading diameter of axle errors, Shi Ji tape running speed is not fast W% sometimes.This situation, the tape running speed during for general record also are same.Here, when setting tape running speed and increase W%, the tape running speed when detecting real-world operation can be obtained the tape running speed deviation of the device that will measure.The increment rate of supposing actual tape running speed is P (%), utilizes wavelength to detect and handles 11 resulting wavelength X, and formula (7), there is following formula (8) to set up.
λ=T×400/P (8)
By formula (8), detect processing 11 wavelength X that obtains and T by wavelength, can obtain actual tape running speed increment rate P (%).Therefore, tape running speed deviation e% is:
e=P-W (9)
Like this, the tape running speed deviation e that tries to achieve also may be displayed on the monitor 8 of Fig. 3.
More than set forth for the measurement mechanism and the method thereof of the relative height sum of errors tape running speed deviation of two magnetic heads of relative one-tenth 180 degree.Self-evident, for 4 magnetic heads of 90 degree configurations at interval etc., or have the magnetic recording system of other a plurality of magnetic heads, utilize the corresponding relation of the phase value deviation of the relative height error of magnetic head and ATF error signal, can obtain magnetic head relative height error equally.
In addition, present embodiment has carried out the scale-of-two processing in the waveform processing of ATF error signal, adopt the wavelength and the phase place of other method signal calculated, for example differentiating detects its vertex position, detects the method for wavelength and phase place, also can draw same result.
Moreover the change conditions of the ATF error signal that has produced under the fast situation when having enumerated tape running speed than general regeneration in the present embodiment adopts additive method that the scanning deviation amount is increased in time pro rata certainly and also is fine.For example, when the setting tape running speed is lower than general speed, clearly, also can obtain same result.
Claims (4)
1, a kind of measuring method of magnetic head relative height, it is the relative height that is used to measure described relatively first magnetic head of second magnetic head of magnetic recording system, and described magnetic recording system comprises: recording first and second pilot signal on the tape with first magnetic head of the second tape running speed playback different with described first tape running speed under first tape running speed; And recording described first and second pilot signal on the described tape with second magnetic head of the described second tape running speed playback under described first tape running speed, described measuring method is characterised in that and comprises following process:
According to first and second pilot signal of the described first magnetic head playback, first generative process of first signal of the time-varying relationship of the difference of generation expression first pilot signal and second pilot signal;
According to first and second pilot signal of the described second magnetic head playback, second generative process of the secondary signal of the time-varying relationship of the difference of generation expression first pilot signal and second pilot signal;
Detect first testing process of the phase place of described first signal;
Detect second testing process of the phase place of described secondary signal; And
Obtain poor between the phase place of described first signal and the secondary signal phase place,, calculate the process of described second magnetic head with respect to the relative height of described first magnetic head according to difference.
2, the measuring method of magnetic head relative height as claimed in claim 1 is characterized in that:
Above-mentioned tape have first magnetic track, second magnetic track and be clipped in first magnetic track and second magnetic track between the 3rd magnetic track, above-mentioned first pilot signal of record in described first magnetic track, above-mentioned second pilot signal of record in described second magnetic track, recording level is 0 pilot signal in described the 3rd magnetic track.
3, a kind of measurement mechanism of magnetic head relative height, it is used to measure the relative height of second magnetic head of magnetic recording system with respect to described first magnetic head, described magnetic recording system has: will under first tape running speed, record first and second pilot signal on the tape, with first magnetic head of the described first tape running speed second tape running speed playback inequality; And will under described first tape running speed, record described first and second pilot signal on the described tape, with second magnetic head of the described second tape running speed playback, described measurement mechanism is characterised in that and comprises:
According to described first and second pilot signal by the described first magnetic head playback, first generating unit of first signal of the time-varying relationship of the difference of generation described first pilot signal of expression and second pilot signal;
According to described first and second pilot signal, generate second generating unit of secondary signal of time-varying relationship of the difference of described expression first pilot signal and second pilot signal by the described second magnetic head playback;
Detect first test section of the phase place of described first signal;
Detect second test section of the phase place of described secondary signal; And
Obtain poor between the phase place of the phase place of described first signal and secondary signal,, calculate the calculating part of described the 2nd magnetic head with respect to the relative height of described first magnetic head according to described difference.
4, the measurement mechanism of magnetic head relative height as claimed in claim 3 is characterized in that:
Above-mentioned tape have first magnetic track, second magnetic track and be clipped in first magnetic track and second magnetic track between the 3rd magnetic track, in described first magnetic track, record above-mentioned first pilot signal, in described second magnetic track, record above-mentioned second pilot signal, in described the 3rd magnetic track, record level and be 0 pilot signal.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP213202/1995 | 1995-08-22 | ||
| JP7213202A JPH0963155A (en) | 1995-08-22 | 1995-08-22 | Inspection method and apparatus for magnetic recording device |
| JP213202/95 | 1995-08-22 |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN01103720.2A Division CN1199172C (en) | 1995-08-22 | 2001-02-06 | Measuring method and device for measuring tape running speed deviation of magnetic recording device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1149173A CN1149173A (en) | 1997-05-07 |
| CN1071042C true CN1071042C (en) | 2001-09-12 |
Family
ID=16635233
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN96109602A Expired - Fee Related CN1071042C (en) | 1995-08-22 | 1996-08-22 | Method and device for measuring relative height of magnetic head of magnetic recording device |
| CN01103720.2A Expired - Fee Related CN1199172C (en) | 1995-08-22 | 2001-02-06 | Measuring method and device for measuring tape running speed deviation of magnetic recording device |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN01103720.2A Expired - Fee Related CN1199172C (en) | 1995-08-22 | 2001-02-06 | Measuring method and device for measuring tape running speed deviation of magnetic recording device |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH0963155A (en) |
| CN (2) | CN1071042C (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5119249A (en) * | 1988-09-22 | 1992-06-02 | Nakamichi Corporation | Tracking error detection circuit using pilot signals during tape reproduction |
-
1995
- 1995-08-22 JP JP7213202A patent/JPH0963155A/en active Pending
-
1996
- 1996-08-22 CN CN96109602A patent/CN1071042C/en not_active Expired - Fee Related
-
2001
- 2001-02-06 CN CN01103720.2A patent/CN1199172C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5119249A (en) * | 1988-09-22 | 1992-06-02 | Nakamichi Corporation | Tracking error detection circuit using pilot signals during tape reproduction |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1345055A (en) | 2002-04-17 |
| CN1199172C (en) | 2005-04-27 |
| CN1149173A (en) | 1997-05-07 |
| JPH0963155A (en) | 1997-03-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1236428C (en) | Optical disk, optical disk servo error control method and its device | |
| US20050024761A1 (en) | Dynamic measurement of head media spacing modulation | |
| CN1129907C (en) | Optical disk device | |
| CN1181487C (en) | Playback method of disk-shaped storage medium | |
| CN1071042C (en) | Method and device for measuring relative height of magnetic head of magnetic recording device | |
| CN100342434C (en) | Optical disc tracking control device and tracking control method thereof | |
| CN1137672A (en) | Automatic tracking apparatus and method therefor during abnormal speed playback | |
| US5577009A (en) | Tracking control system for generating a variable still jump signal | |
| CN1224022C (en) | Oblique control for optical disk recording reproducing apparatus | |
| CN114779279B (en) | Method and system for scanning and measuring contaminated plane | |
| CN1088239C (en) | Apparatus for reproducing tape-shaped recording medium | |
| JPH079713B2 (en) | Optical disk defect evaluation system | |
| US5231619A (en) | Optical disk apparatus having improved tracking servo mechanism | |
| JP3462328B2 (en) | Spindle servo device for optical disk player | |
| US20030128639A1 (en) | Optical disc device | |
| US7916419B2 (en) | Posture adjustment method of magnetic head | |
| US5268891A (en) | Optical recording/reproducing apparatus which reduces seek time by timing initiation of tracking control based upon characteristics of record medium vibrations relative to an optical pick-up head | |
| JP2564266B2 (en) | Optical disk drive seek method and optical disk drive | |
| KR0185185B1 (en) | Helical scan-type rotary head drum unit | |
| CN1790492A (en) | Optical disk apparatus and optical disk evaluation method | |
| US20050152241A1 (en) | Information disc recorder/reproducer and method for controlling recording/reproducing speed | |
| CN1057169C (en) | Tracking control method for VCR and apparatus thereof | |
| JP2696949B2 (en) | Head position control method | |
| JPH0467124B2 (en) | ||
| CN1813302A (en) | Disk positioning information writing method and device, information recording and reproducing device and recording medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |