JPS62146452A - High speed search system - Google Patents

Abstract

PURPOSE:To keep a relative speed at the time of rapid scanning by generating an area signal from a drum position signal and a signal corresponding to N times a drum motor control signal, detecting the relative speed of tape traveling to head rotation from a reproduced output signal of a rotary magnetic head, and controlling the drum motor by information averaged in each section. CONSTITUTION:An area signal is generated without the influence of a relative speed with high resolution by using a drum position signal from a drum FF 7 as a reference and using a clock corresponding to N times the control signal of a drum motor control signal oscillator 8. A relative speed detecting means 2 is driven by the area signal, information reproduced by a rotary head 9 is read out at a good timing and averaged 10 in each section, the averaged information is compared with a relative speed objective value by an adder/subtractor 11, and a control signal is applied to a drum motor controller 12 to control the rotational frequency of the drum 13 and to maintain the relative speed. In this method, the relative speed of the tape traveling speed to the head rotating speed can be maintained even at a rapid searching.

Description

[Detailed Description of the Invention] "Objective of the Invention" (Industrial Application Field) The present invention relates to a high-speed search system for a rotating magnetic head type digital audio tape player (hereinafter referred to as R-DAT), and is particularly necessary for high-speed search. This paper relates to a relative speed control system.

(Prior art/problems to be solved by the invention) R-DA
At T, the magnetic tape is run at several hundred times the normal running speed, and the subcode area is recorded.

By reproducing and reading information signals recorded on a magnetic tape such as PCM-ID, the position of the magnetic tape can be detected at high speed. This kind of operation is called high-speed search.

In order to reproduce and read the information signals recorded on the magnetic tape during such high-speed searches, the relative speed between the magnetic tape running speed and the rotational speed of the rotating magnetic head must be determined in terms of reproduction output and bit synchronization. It needs to be the same as in steady state.

1,! Since nL and R-DAT do not have a device that can directly monitor the magnetic tape speed like VTR17) CTL, etc., in the reel-to-reel magnetic tape running system,
The magnetic tape is rotated at a high speed at a constant speed (for example, 20
It was difficult to keep the vehicle running at a constant speed of 0 times. It is also possible to run at a constant speed using a capstan motor, but it has not been possible to run the magnetic tape at several hundred times the steady speed because there are concerns about the reliability of the capstan motor.

The present invention has been made in view of the above-mentioned points, and its object is to provide a high-speed device equipped with a control system that maintains the relative speed between the running speed of a magnetic tape and the rotational speed of a rotating magnetic head during a high-speed search. Our goal is to provide a search system.

"Structure of the Invention" (Means for Solving the Problem) The high-speed search system according to the present invention provides a drum (cylinder) position signal and a drum motor control signal multiplied by 8 (or a drum position signal multiplied by 8). an area signal generating means for generating an area signal using an area signal (signal obtained by the rotation of the rotating magnetic head); and detecting the relative speed between the running speed of the magnetic tape and the rotational speed of the rotating magnetic head from the reproduction output signal of the rotating magnetic head when the area signal is supplied. Relative velocity detection means, interval averaging means for obtaining interval averaged data of relative velocity detection output;
The problem is solved by providing a drum motor controller that is limited based on data obtained by averaging over a section.

(Function) During high-speed search, a signal obtained by multiplying the drum position signal and the drum motor control signal by eight is supplied to the area signal generation means, which generates an area signal that instructs the timing to detect the relative speed, and detects the relative speed. Apply to the means. The relative speed detection means detects the reproduction output signal of the rotating magnetic head according to the timing of the applied area signal.
Detects the relative speed between the magnetic tape running speed and the rotational speed of the rotating magnetic head, and sends the detection signal to the section averaging means.
In the section averaging means, there is a risk that the preceding stage relative speed detecting means may cause a detection error due to dropout, etc., so this is to prevent this influence.

The output of the relative speed detection means is averaged over a section, and the resulting data is used as the relative speed. By controlling the drum motor controller and controlling the number of rotations of the drum based on the data of the section averaging means, it is possible to maintain the relative speed of the reel-to-reel high-speed magnetic tape search system.

(Example) An example of a high-speed search system according to the present invention will be described based on FIGS. 1 to 3. FIG. 1 is a block diagram showing the overall configuration, FIG. 2 is a block diagram showing the configuration of area signal generation means, and FIG. 3 is a timing chart for explaining FIG. 2.

As mentioned above, R-DAT does not have a device that can directly monitor the running speed of a magnetic tape, such as the CTL of a VTR, so it was recorded on a magnetic tape. subcode area,
High-speed search is possible by reading information signals such as PCM-ID. However, during this high-speed search,
In order to read information signals recorded on a magnetic tape, it is necessary to keep the relative speed between the running speed of the magnetic tape and the rotational speed of the rotating magnetic head the same as in a steady state from the viewpoint of reproduction output and bit synchronization.

In order to maintain the relative speed constant, (1) detect the relative speed by some means, maintain the drum (cylinder) rotational speed at a constant value, and then adjust the magnetic tape running speed. control and maintain the relative speed, or (2
) There is a method of running the magnetic tape at an appropriate speed and controlling the number of rotations of the drum to maintain the relative speed.

Comparing the means (1) and (2) above, controlling the drum rotation speed has a greater influence on the relative speed than controlling the magnetic tape running speed, so the gain of the relative speed control system The fact that it requires less
Since controlling the drum causes less disturbance, the latter method (
2) is considered to be a better method of controlling the drum rotation speed.

The present invention attempts to realize the above-mentioned relative speed control system by controlling the drum rotation speed.

The high-speed search system of the present invention, as shown in FIG.
The relative velocity is directly detected from the information signal recorded on the magnetic tape 1. The recording signal of R-DAT has a frequency of 1.
/72fcn = 13.0.87KHz (here fcu is 9.408MHz) to 1/2fc++ =
Signals up to 4.704 MHz are used. Among these, the 1/72fcn signal is far apart in frequency from other signals, and the closest frequency is 1/18fc++ = 522
．． The frequency is 878 KHz, which makes it easy to distinguish from other signals, and is always recorded on each tractor, making it easy to detect.

In the case of the present invention, the relative speed during high-speed search is detected, for example, by sensing the period of the 1/72fc+ signal.

As mentioned above, since the relative speed is directly detected from the magnetic tape 1, it is necessary to maintain the magnetic tape running speed within a range in which the relative speed detecting means 2 can detect the relative speed under any conditions. be. In order to create this state, a simple magnetic tape running speed control system 5 is constructed in the magnetic tape running system consisting of the reels 3 and 4. This magnetic tape running speed control system 5 is not provided for the purpose of keeping the magnetic tape running speed constant due to changes in the length of the magnetic tape 1, etc., but rather due to changes in various parameters of the magnetic tape 1. The magnetic tape running speed range, including
For example, if the magnetic tape running speed range is from the minimum A to the maximum B, the minimum running speed A and the maximum running speed B may be geared.

Furthermore, in addition to maintaining the magnetic tape running speed, the drum motor unit is configured such that the drum rotational speed range is limited to a rotational speed at which a target relative speed can be obtained at minimum A and maximum B of the magnetic tape running speed. do. The two configurations described above create a state in which the relative speed detection means 2 can constantly detect relative speed.

However, even if the relative speed detecting means 2 tries to detect and read a signal of 1/72 fco, for example, which is a signal recorded on the magnetic tape 1, the signal is not continuously reproduced and supplied. , is periodically regenerated and supplied. Therefore, unless the relative speed detection means 2 is configured to operate when the signal to be read is reproduced, there is a high possibility that it will detect an incorrect signal and malfunction, and sufficient reliability will not be obtained. .

Therefore, the signal (1/7
24cH) is generated, and the relative speed detection means 2 is operated by this area signal, thereby improving reliability.

This area signal can be easily generated when the drum rotation speed is constant as in the steady mode, since it is sufficient to generate an area signal that mechanically commands the timing, but in high-speed search mode, the drum rotation speed is not constant, so
It cannot be generated in ms.

Therefore, as shown in FIG. 2, an area signal generating means 6 is configured to generate an area signal.

This area signal generating means 6 receives a drum position signal ■ from a drum flip-flop (hereinafter referred to as DFF) 7,
The area signal is generated by a signal obtained by multiplying the control signal (2) of the drum motor control signal oscillator (hereinafter referred to as FG) 8 by N.

The decomposition part of the control signal ■ of FG8 is about 10 degrees, so by multiplying the frequency of the control signal ■ by N times, the decomposition part of the control signal ■ becomes N
It's doubled. Therefore, the drum position signal of DFF7■
In contrast, the segment area, that is, the information signal (+/72fc) that detects the relative velocity recorded on the magnetic tape l
Since the angle of the area u) is known in advance, the height can be determined by counting the pulses corresponding to that position using the drum position signal ■ as a reference and using the clock ■ that is N times the control signal ■ of FG8. It is the circuit section that generates the area signal (■) with resolution.

According to the area signal generating means 6 as described above, it is possible to generate an area signal that instructs the relative speed detection timing without being influenced by the relative speed.

When the area signal (2) generated in this manner is supplied to the relative speed detection means 2, the relative speed detection means 2 enters the detection operation state and transmits the information signal reproduced by the rotating magnetic head 9 at the timing. Read carefully, interval modifier IO
send to

The section averaging means 10 is provided in order to minimize the influence of the relative velocity detecting means 2 at the preceding stage, which may generate a detection error due to dropout of the reproduced signal or the like.

Particularly in the high-speed search mode, dropouts as described above may continue for a relatively long time. Therefore, this section averaging means 10 converts the output of the relative speed detection means 2 into
The output of the 9-section averaging means 10, which averages the data using a section averaging circuit and outputs the data as a relative speed, is compared with a relative speed target value set in advance in an adder/subtractor 11, and then controlled by the drum motor controller 12. is supplied as a signal and controls the rotation speed of the drum 13,
Relative speed can be maintained.

"Effects of the Invention" As is clear from the above embodiments, according to the high-speed search system according to the present invention, in R-DAT, by reading the period of the information signal component having a predetermined frequency in the reproduced output signal, the relative A change in speed is detected as a change in the period of the information signal having the predetermined frequency, and the drum motor controller is controlled by the detected relative speed detection signal to control the rotational speed of the drum;
It is possible to maintain the speed relative to the running speed of the tape.

[Brief explanation of drawings]

1 to 3 show an embodiment of a high-speed search system according to the present invention, and FIG. 1 is a block diagram showing the whole,
FIG. 2 is a block diagram showing area signal generation means, and FIG. 3 is a timing chart of the blocks in FIG. 1; Magnetic tape 2; Relative speed detection means 3.4; Reel 5; Magnetic tape running speed control system 8: Area signal generation means 7; Drum flip-flop 8 Drum motor control signal generator 9: Magnetic head 10; Section average Means 12; Drum motor controller 13; Drum

Claims (4)

[Claims] (1) In a digital audio tape player using a rotating magnetic head, an area signal generation means for generating an area signal using a drum position signal and a signal obtained by multiplying the drum motor control signal by N, and the area signal is supplied. a relative speed detection means for detecting the relative speed between the magnetic tape running speed and the rotational speed of the rotary magnetic head from the playback output signal of the rotating magnetic head; an interval averaging means for obtaining data obtained by averaging the relative speed detection output over the interval; A high-speed search system comprising: a drum motor controller controlled based on averaged data. (2) The area signal generating means is configured to use the drum position signal as a reference, count using a clock N times the control signal of the drum motor, detect the area, and generate the area signal. The high-speed search system described in item 1. (3) The high-speed search system according to claim 1, wherein the area signal generating means is configured to generate the area signal using a signal obtained by multiplying the drum position signal by N. (4) In order to maintain the magnetic tape running speed within a range in which the relative speed can be detected, the relative speed detection means has a magnetic tape running speed control means using a reel motor controller, and a drum rotation speed that is the minimum of the magnetic tape running speed. 2. The high-speed search system according to claim 1, comprising: and a drum motor unit whose rotational speed is limited to a maximum rotational speed at which relative speed can be detected.