JPS61265764A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To use two pilot signal detection circuits for the detection of three pilot signals by detecting respectively pilot signals recorded on a track and its adjacent tracks, in total 3 tracks, synthesizing its reproducing level with an optional ratio and obtaining a tracking error signal. CONSTITUTION:A magnetic tape 1, a head 2, a track 3 controlling the scanning of the head 2, a scanning track and both adjacent tracks 4, 5 are provided. Further, band pass filters (BPF) 6, 7, 8 detecting respectively the pilot signals recorded on the tracks 3, 4, 5 rectifier circuits 9, 10, 11 detecting the amplitude level of the outputs of the BPF 6, 7, 8 variable gain amplifiers 12, 13, 14 multiplying the output of the rectifier circuits 9, 10, 11 by alpha, beta, gamma respectively (e.g., -1<=alpha<=1, 0<=beta<=1, -1<=gamma<=0), an adder 15 synthesizing the outputs of the variable gain amplifiers 12, 13, 14, a reference power supply 16, a differential amplifier 17 and an output terminal 18 for a tracking error signal are provided.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a magnetic recording/reproducing device, and in particular records a pilot signal by cyclically switching the frequency for each track, and uses the pilot signal during reproduction to record an arbitrary signal. The present invention relates to a magnetic recording/reproducing device having a tracking control device that controls a head in a tracking state.

[Background of the invention]

ATF method (41 public I1) adopted for 8 mm video
No. 859-31795) had the advantage of eliminating the need for the conventional CTL head, but it did not take into consideration so-called tracking adjustment, which is controlling the head to an arbitrary position with respect to the track. Although the 1 racking control device described in JP-A No. 58-159259 enables tracking IL1M, as shown in FIG. A circuit is required! This method has the drawback that it requires a large increase in circuit size, and that it is not possible to perform tracking adjustment in both directions at the same time.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording/reproducing device that has a simple configuration, can stably perform tracking adjustment in both directions, and does not cause deterioration in servo performance.

[Description of the invention]

The present invention is characterized by detecting pilot signals recorded on three tracks, the track scanned by the head and the 70-track track, and determining the playback level. The feature is that the tracking error signal is obtained by combining at an arbitrary ratio.
, '1. Another aspect of the present invention is to provide a variable delay circuit that arbitrarily delays the head switching pulse, and to realize detection of three pilot signals with two pilot signal output circuits. There is a point 1c that was K.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to Examples. FIG. 1 is a block diagram showing an embodiment of the present invention for realizing tracking adjustment.

In the figure, 1 is a magnetic tape, 2 is a head, 3 is a track for controlling the scanning of the head 2 (hereinafter referred to as a scanning rack), and 4 and 5 are both adjacent tracks. Also, 6
．． 7 and 8 are track 3.

The pilot signals recorded in 4 and 5 are detected in the band FI [(hereinafter referred to as BPF 6), 9.

10 and 11 are II current circuits that detect the amplitude levels of the outputs of the BPFs 6 and 7.8, and 12, 13.14 are rectifier circuits 9 and 1.
15 is a variable gain amplifier 12 which multiplies the output of 0.11 by α, β, and r, respectively (for example, −1≦α≦1, o≦β≦1.-1≦r≦0); , 13 and 14, 16 is a reference power supply, 17 is a differential amplifier (a comparator is also possible), and 18 is an output terminal of the toshikinque 2 signal.

Next, the circuit operation of this embodiment will be explained with reference to FIG. FIG. 2 is a diagram illustrating the tracking error output with respect to the amount of tracking deviation.

In FIG. 1, for example, a=0, β=1 and r=-
1, the tracking error output is the solid line 21 in Figure 2.
The point where the outputs of the IL flow circuits 10 and 11 are at the same level (point A) becomes the tracking lock point, as shown in FIG. A lock is established when the pilot signals reproduced from both adjacent tracks 4 and 5 are at the same level, and at this time the head is controlled to be centered on the scanning track.

If t, a=-1, β=12 and y=Q, the tracking error output is point i1i! in Figure 112. 5 as shown in 22, and the point where the outputs of the rectifier circuits 9 and 1o are at the same level (point B) becomes the tracking lock point.

') t, the point where the pilot signals reproduced from the scanning track 3 and the adjacent track 4 become the same level, that is, the boundary between the scanning track 3 and the adjacent track 4, in other words, the amount of tracking deviation is 0.5 pitch (Pltah) (1
A pitch corresponds to one track width. ) is controlled so that the head comes to the position.

On the contrary, 1ow1. In the case of β-gon Q and r--1, the tracking F-output becomes as shown in the dot chain-23 in Figure 2, and the point (point C) where the outputs of NIL@paths 9 and 11 are at the same level is the tracking This is the lock point. The point at which the pilot signals reproduced from scanning track 3 and adjacent track 5 become the same level, that is, 7i! Survey 2 Tsuku 3
and the boundary between adjacent tracks 5, in other words, the amount of tracking deviation is controlled by 11G when the head comes to the position of →5 pitches.

To summarize the above, variable gain amplifier 12゜13.
For example, set the values of gains α, β, and r of 14 to −1≦α and 1.0≦
β≦1. By arbitrarily and continuously changing the range of −1≦r≦00, ±0.0 in both directions with respect to the running track 3.
so that the head 2 can be placed at any position within a range of 5 pitches.
It becomes possible to perform tIII141 on the head 2. Also, the tracking error output in FIG. 2 is also at the tracking lock point A.

It exhibits point-symmetrical characteristics with respect to B and CK, and stable servo performance can be achieved.

Next, variable gain increase @i! 12, 13.14 gains α, β
, r will be described with reference to FIG. 3.

In FIG. 3, 31 is a first adder that obtains a difference signal between the outputs of rectifiers 9 and 10, 32 is a second adder that obtains a difference signal between the outputs of rectifiers 9 and 11, and 33.34 is an adder 31.
．． A variable gain amplifier that multiplies the output of 32 by 1 or 7 (for example, 0≦k).

l≦1). Now, the pilot signal reproduction level of scan track 3, that is, the output of fi@9, is set to 1, and the pi bit signal reproduction level of both adjacent tracks 4.5, that is, pL.
'If the outputs of m10.11 are b and e, respectively, then
The outputs of t and 32 are frozen as b-a and a-a, respectively, and the output of the differential amplifier 17 becomes 1(e-a)-k(ba).

Here, in the case of k=1=1, the output of the differential amplifier 17 becomes c-b, and the head is controlled to the point where the snow Q (6-1) occurs, that is, the center of the scanning track 3. This corresponds to the above-mentioned case of αwQ, β=l, r=--1.

Further, in the case of k=1, /=O, the output of the differential amplifier 17 becomes a −b, and the head is controlled to the point @ −b−Q, that is, the boundary between the scanning track 3 and the adjacent track 4. . This corresponds to the above-mentioned case of α=-1°β=1 and f=o.

Conversely, in the case of kWRO, lxl, the output of the differential amplifier 17 becomes e - a, and the head is controlled to the point where C-@wQ, that is, the boundary between the scanning track 3 and the adjacent track 5. This is based on the above-mentioned α=1. β scale 0. This corresponds to the case of f--1.

In this way, even with the configuration shown in FIG. 3, it is possible to obtain a tracking adjustment range of ±0.5 pitch around the scanning track 3, as in the case of FIG. .

Next, BrF3.7 shown in Figures 1 and 3
．． A specific example of No. 8 will be explained using FIGS. 4.5 and 6.

44, 41 is an input terminal for the regenerated pilot signal, 42 is a preamplifier (an automatic gain control amplifier (hereinafter referred to as AGC assot) that keeps the output level constant), 43.44$P and 45 is the output signal of the preamplifier 42 and local pilot signals (LOCAL PLT) input from input terminals 46, 476 and 48, respectively.
) is calculated. 5 frequency converters

It is.

The circuit operation will be explained with reference to at in FIG.

Table 1 Four types of pilot signals A -k with different frequencies are recorded for each track on the tape, /I = 6.5 h' -k = 7.5 fw%f, = 115f = 95
f1tch-h=/s-/4=/II-to-/l=/s
The frequency configuration is -A=51M.

In this case, the local pilot signal (2) as shown in Table 1 (
LOCAL PLT) are input to frequency converters 43-45 via input terminals 46-48, respectively.

In the frequency converters 43 to 451C, the regenerated pilot signal output from the preamplifier 42 is multiplied by each local pilot signal, and the regenerated pilot signal and
The difference frequency component of the local pilot signal is output.

Therefore, /i+BPF49~51 ”1: is Table I
A pilot signal indicated by K is detected.

Here, 71BPF49. fHBPF50 and/
The reason why i+BPF51 is as shown in Table 1 will be explained.

Now, scanning track 3, adjacent track 4. and the pilot signal recorded on each of the adjacent tracks 5 is f
Consider the case where the local pilot signals applied to input terminals 46.473P and 48 are f*+fs' and f, that is, the leftmost case in Table 1.

At this time, the reproduced pilot signals ft, f+, and ft are possibly inputted from the input terminal 41. These regenerated pilot signals are then sent to the frequency converter 4.
3.Enter each of 44& and 45.

Therefore, when the local pilot signal f1 is applied to the input terminal 46 of the frequency converter 43, the frequency converter 43
From, (fI-ft), (fa-ft).

and Cfxf*) is output. Then, when these difference signals are input to the fHBPF 49, (f.

Only the difference signal of -f, ) passes through the fuBPF 9, while the other difference signals (fa7t) and (ft-f2) are blocked from passing. Therefore, only signals related to the reproduced pyroft signal f1 are taken out at the output of the fHBPF 49.

On the other hand, the output of the frequency converter 44 to which the local pilot signal f is applied to the input terminal 47 is (ft-fa
) l (fa-fs>s?! and (ft-fa).

When these difference signals are input to the fHBPF 50 K, only the signal related to the regenerated pilot signal f4 is extracted from the fHBPF 50.

Similarly, the output of the frequency converter 45 to which the local pilot signal f1 is applied to the input terminal 48 is (fr-f
l) , (f4 71) and (fm-v+),
The output of the fHBpF 51 connected to the cough frequency a converter 45 is only a signal related to the regenerated pilot signal f.

Thereafter, even if one pilot signal recorded on scanning track 3 becomes fa, f4, each fuBPF49, 50 J? and 51, signals related to the regenerated pilot signal listed in the 's1 table are extracted.

As is clear from Table 1, the output of ZoBPF 49 is always the pilot signal recovered from the scanning track;
It should be noted that the output of 7mBPF 50 and 51 is always the pilot signal adjacent to the scan track.

The outputs of said nine BpFs 49, 50 and 51 are then sent to rectifiers 9, 102 and IIK, respectively. The output of the rectifier 9 becomes the pilot signal reproduction level of the scanning track 3, and the output of the rectifier @to, ii becomes the pilot signal reproduction level of the adjacent track 4.5, respectively.

Next, in Fig. 5, 61 is 3 to detect the 3 fu acid component.
f118PF, and other symbols are the same as in FIG. 4 or equivalent. This specific example is based on the 7HBP of the first A body example.
By replacing F51 with 3 hBPF K Ill, two frequency converters are used to operate in the same manner as in the first specific example.

In this example, by applying local pilot signals as shown in Table 2 to input terminals 46$1- and 47, the fuBPF 49.

From 50 $P and 3 fgBPF 61, an output signal similar to that of the first example can be obtained.

Table 2 FIG. 6 shows a third specific example of the BPFs 6, 7 and 8. In Figure 6, 71.72 is 27g+
4 BPF to detect j's+ component, 73, 7
42 and 75 each indicate a switch, and other symbols indicate the same or equivalent components as in FIG. 5.

This third specific example is 7 mBPF 50.2 hBPF
713 fmBPF 61 and 4 fuBPF 'L
2 and 4 types of BPF are provided, and the subsequent switch 73~
By switching using the head switching pulse at 75,
By using one frequency A converter 44, the same operation as the specific example shown in FIG. 4 can be expected.

In this specific example as well, as shown in Table 3, the output of switch 1 73 is at the pilot signal reproduction level of scanning track 3, and the outputs of switches 74 and 75 are the pilot signal reproduction level of adjacent tracks 4 and 5, respectively. become the level.

Next, still another embodiment of the present invention in which toking adjustment is realized by arbitrarily delaying the head switching pulse will be described with reference to Figures 7 and 8. T! J4
FIG. 7 is a block diagram of this embodiment, and FIG. 8 is a time chart of output signals of the main blocks in the block diagram.

Table 3 In the figure, 81 is a low frequency filter (hereinafter referred to as LPF).

), 82.83 is the local pilot signal input to the frequency converters 43 and 44, and is switched by the output signal of the KXOR (exclusive OR circuit) 84.
y f, 84 i! EXOR, 85)'! .

A local pilot signal generator 86 is an input terminal for a head switching pulse, and 87 is a variable delay circuit that delays the head switching pulse by an arbitrary amount.

In addition, in FIG. 8, 8-a is a head switching pulse;
-b is the pilot signal recorded on scanning track 3, 8-c is the pilot signal recorded on adjacent track 4, 8-d is the pilot signal recorded on adjacent track 5, and 8-e is the pilot signal of KXOR84. The output signal S-t is a local pilot signal input from the switch 82 to the frequency converter 43, and 8-g is a local pilot signal input from the switch 83 to the frequency converter 44.

Furthermore, 8-h is the output of 7MBPF 49, 8-1 is f
The output of the HBPF 50, 8-J is the output of the rectifier 9, 8- is the output of the rectifier IO, and 8-1 is the output waveform of the adder 31.

Now, when the delay amount of the variable delay circuit 87 is exactly 0.5 field, the output signal of EXOR84 is 8- or 5ON.
Let's consider the case of . As can be seen from FIG. 8, during the period when there are 10 output signals 8-. The pilot signal of the scanning track 3 is detected.Conversely, during the period when the 1 output signal 8-.
MBPF49 sends the pilot signal for scanning track 3!
The /HBPF 50 of 1!2 detects the pilot signal of the ilI contact track 5.

Therefore, the output of the adder 31 is such that the output signal 8-.
The period of 32 corresponds to the output of the first adder 31 in the embodiment shown in FIG. It corresponds to what was done.

The output of this adder 31 is the LPF 81 (the cutoff frequency is
A frequency of 30 Hz or less is suitable, but there is no particular limitation. ) and then comparing it with the reference power supply 16 using the differential amplifier 17, it is possible to obtain the same signal as in the embodiment of FIG. In this case, toking adjustment is performed by changing the delay amount of the variable delay circuit 87 to adjust the output signal s.
This is done by changing the deity of -e.

That is, as the period of the output signal 8-e f) ``high'' becomes longer, the gain 44 of the first variable gain amplifier 33 in FIG.
This corresponds to a decrease in k, and conversely, the output signal 8−・'−
As the period of "return" becomes longer, this corresponds to a decrease in the gain l of the second variable gain amplifier 34 in the figure.

In this embodiment, the frequency at which the local pilot signal is switched is approximately 60 Hz, but this frequency is changed to a higher frequency (for example, 10 Hz).
0 Hz to I KHz).

In addition, in this embodiment, switches 82 and 83 EXOR84
, and the switching of the local pikes H6 performed by the configuration of the variable delay circuit 87 can also be realized by directly delaying the head switching pulse input to the local pilot signal generator 85, as shown in FIG.

According to the above embodiment, the detection of three pilot signals can be realized with a 211m pilot signal detection circuit, and the head switching pulse can be arbitrarily set to 1! ! By extending the head, the 1gl@head can be brought to any desired position, which is advantageous in that tracking adjustment can be realized.

Therefore, an overall block diagram of a servo circuit to which an embodiment of the present invention is applied will be explained using diagram 1s10.

In Figure 10, 91 and 92 are audio signal input and output terminals, 93 and 94 are video signal input and output terminals, 95 is an audio signal and video signal processing circuit, 96 is a recording and playback amplifier, and 97 is a Magnetic tape, 98 is ＼RAD,
99 is a capster/, and 100 is a rotating cylinder. In addition, 101 is a capstan motor, lυ2 is a drum motor, 1OA is a frequency discriminator that detects the rotational speed of the ram motor, 104 is a reference 30Hz generator,
105 is a phase comparator, and 106 is an adder. moreover,
107 is a tracking error detection circuit using a pilot signal; 108 is a local pilot signal generator; 10
9 is an adder; 110 is a frequency discriminator that detects the rotational speed of the capstan motor; 111 is a drum tack head that detects the rotational phase of the rotating cylinder 100;
A head switching pulse generator 112 generates a head switching pulse from the output of the drum tack head 111.

As shown in FIG. 1θ, the servo circuit is roughly divided into two systems. The first is a drum servo system that controls the rotational speed of the head. This is done by controlling the cylinder 1000 rotation frequency by f-ma conversion of the frequency discriminator 103, and by using the head switching pulse and the reference 30 by the phase comparator 105.
By comparing the phase with Hz, the cylinder 100
This configuration controls the 0 rotation phase.

The second is a gear tan servo system that feeds the tape at 9 speeds. Similar to the drum servo system, the rotational frequency of the capstan motor is controlled by the frequency discriminator 110, and the tracking error detection 1gIM using the pilot signal described above is used.
107 performs tracking control.

Although the embodiments of the present invention have been described above, a sample Hall circuit that maintains the directivity is added to the stage of the differential amplifier circuit 17 (this is possible even after S), although it is not shown. By providing this, reliable reproduction is possible even in cases where the reproduced pilot signal is lost for m periods, such as during dubbing, for example. In addition, the hBPF of the example is 3f tuna B
tIL may be replaced by PF.

〔Effect of the invention〕

According to the invention, the scanning trunk of the head and its both v
Since the pilot signals of the 8-track tracks are detected and combined at an arbitrary ratio to form the 2-track signal, only one tracking error output circuit is required, resulting in a relatively simple configuration. Moreover, it has a great effect in that tracking adjustment in both directions can be achieved stably.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a block diagram showing a tracking error output for tracking deviation, FIG. 3 is a block diagram showing a second embodiment of the present invention, and FIG. 5 and 6 are block diagrams for explaining the first, second and third specific examples of the BPF of the #2 embodiment, respectively, and FIG. 7 is a block diagram of the BPF of the present invention! A block diagram showing the 2S3 embodiment, FIG. 8 is a time chart for explaining the main signals of the i3'A embodiment, and FIG. 9 is a +41
A modified example of the third embodiment is shown in a Bonapronoque diagram, and FIG. 10 is a block diagram of the entire sage circuit to which the embodiment of the present invention is applied. 3...Scanning track, 4.5...Adjacent track, 6
17.8... BPF, 9, l O, l 1...
- Rectifier circuit, 12° 13.14, 33.34... Variable gain amplifier circuit, 15.31.32... Adder, 43,
44.45...Frequency converter, 82.83...Switch, 87...Variable Mg circuit representative Patent attorney Michihito Hiraki Figure 5 Figure 9 Figure 8

Claims (4)

[Claims] (1) Tracking adjustment in both directions can be performed in a magnetic recording/reproducing device that performs tracking control of a rotating head using four types of pilot signals recorded in a cyclic order with different frequencies for each track. 1. A magnetic recording and reproducing apparatus, comprising a tracking error detection means, the rotary head being able to be controlled to any position. (2) The tracking error detection means includes a first bandpass filter that detects a pilot signal recorded on a track to be scanned by the head, and a first bandpass filter that detects a pilot signal recorded on both adjacent tracks of the track. 2nd to detect
, a third bandpass filter, and first, second, and
a third amplitude level detector; first, second, and third variable gain amplifiers that amplify the outputs of the first, second, and third amplitude level detectors, respectively; Claim 1, characterized in that the adder is configured to combine the outputs of the third variable gain amplifier, and the differential amplifier is configured to compare the output of the adder with a reference voltage. Magnetic recording and reproducing device. (3) The tracking error detection means includes a first bandpass filter that detects a pilot signal recorded on a track to be scanned by the head, and a first bandpass filter that detects a pilot signal recorded on both adjacent tracks of the track. 2nd to detect
, a third bandpass filter, and first, second, and
a third amplitude level detector; first and second adders that subtract the output of the first amplitude level detector from the respective outputs of the second and third amplitude level detectors; It is characterized by being comprised of first and second variable gain amplifiers that amplify the output of the second adder, respectively, and comparison means that receives the outputs of the first and second variable gain amplifiers as inputs. A magnetic recording/reproducing apparatus according to claim 1. (4) The tracking error detection means includes first and second bandpass filters that detect a pilot signal recorded on a track to be scanned by the head and a pilot signal recorded on one adjacent track; first and second amplitude level detectors that detect the amplitude levels of the output signals of the first and second bandpass filters, and obtaining a difference signal between the outputs of the first and second amplitude level detectors; 2. The magnetic recording and reproducing apparatus according to claim 1, comprising an adder and a variable delay circuit that arbitrarily delays a head switching signal.