JPH0223559A - Information signal reproducing device - Google Patents

Abstract

PURPOSE:To enable the good tracking control on whatever recording medium out of its plural kinds by changing signal processing characteristics of a pilot signal processing means in accordance with the recording medium under reproducing a pilot signal. CONSTITUTION:A signal regenerated from a rotary magnetic head of a rotary drum 5 is inputted via a regenerative amplifier 6 to a video signal processing circuit 7 and filter amplifiers 8 and 9. The regenerative video signal is restored to its original signal form by the circuit 7 to be outputted from an output terminal 13. A switch 20 is connected to the side of A when a tape 4 inside a cassette 1 is an MP tape and to the side of B when it is an ME tape according to a detection signal, a signal processed by filtering and amplifying the pilot signal suitable for each individual tape is outputted from the filter amplifiers 8 and 9. This signal is inputted to a tracking signal processing circuit 11, and a tracking control signal after signal processing is outputted to a capstan driving system circuit 12 so as to perform the tracking control.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an information signal recording device, and more particularly to a device for reproducing an information signal from a recording medium on which a tracking control pilot signal is recorded together with the information signal. be.

[Prior Art] Conventionally, a method has been known in which a plurality of types of pilot signals of predetermined frequencies are recorded together with an information signal at the time of recording, and tracking control is performed based on the reproduction level of the pilot signal at the time of reproduction. The four-frequency system used in consumer video tape recorders (VTRs) falls under the above-mentioned method.

However, even if the recording level is the same, the reproduction level of the pilot signal to be reproduced differs depending on the type of recording medium. Conventional playback devices generally have automatic gain control (A
GC) circuit was provided, and this AGC circuit compensated for the difference in reproduction level.

[Problems to be Solved by the Invention] However, when signals are recorded in the same format on multiple types of recording media with greatly different characteristics, it becomes impossible to compensate for the difference in the reproduction level of the pilot signal, and one of the When reproducing signals from a recording medium, good tracking may not be possible in some cases.

For example, in a VTR that performs 4-frequency tracking control, metal-coated tape (hereinafter referred to as MP tape) and metal-deposited tape (hereinafter referred to as ME tape) are used in the same format.
In a system that can record a video signal and four types of pilot signals at the same recording level, the playback signal level in the low frequency range of the ME tape will be considerably lower than that of the MP tape, and the S/N will also be lower. It will deteriorate. In this case, if a pilot signal processing circuit for MP tapes is used, it may be impossible to perform tracking control using pilot signals reproduced from ME tapes. This is not just a matter of the playback level being low, but the AGC
This is also due to the fact that the noise component in the low frequency range increases due to the effect of the circuit.

With such an object in mind, the present invention provides good tracking when reproducing information signals and tracking control signals in the same format on recording media with different characteristics, regardless of the recording medium. An object of the present invention is to provide an information signal reproducing device that can be controlled.

[Means for Solving the Problems] With the above object in mind, the information signal reproducing device of the present invention is a device for reproducing the information signal from a recording medium on which a tracking control pilot signal is recorded together with the information signal. a determining means for determining the type of the recording medium; a reproducing head for reproducing the information signal from the recording medium; and a pilot signal processing for forming a tracking control signal using the pilot signal reproduced from the recording medium. control means for controlling the relative position of the reproducing head and the recording medium based on the tracking control signal;
The apparatus is configured to include switching means for switching the signal processing characteristics of the pilot signal processing means based on the determination result of the determination means.

[Function] By configuring as described above, the signal processing characteristics of the pilot signal processing means can be switched depending on the recording medium on which the pilot signal is being reproduced, and can be set to a processing characteristic suitable for the recording medium. Good tracking control can be achieved when reproducing information signals from any of the various types of recording media.

[Embodiment] Hereinafter, an embodiment in which the present invention is applied to a VTR that performs four-frequency tracking control will be described.

FIG. 1 is a diagram showing a schematic configuration of a reproduction system of a VTR as an embodiment of the present invention. In the figure, 1 is a cassette in which a magnetic tape is stored, and 2 is a detection hole provided in the housing of the cassette L. , it is indicated whether the magnetic tape, MP tape, or ME tape stored in the cassette 1 is stored depending on whether the detection hole 2 is open or closed.

3 is a detection device for mechanically detecting whether the detection hole 2 is open or closed, and outputs a detection signal indicating the detection result.

Further, 4 is a magnetic tape, 5 is a rotating head drum having a rotating magnetic head near its outer periphery, 6 is a playback amplifier, 7 is a video signal processing circuit, 8 is a filter and amplifier for MP tape, 9 is a filter and amplifier for ME tape. an amplifier; 10 is a switch that is switched according to the detection signal; 11 is a well-known tracking signal processing circuit using a four-frequency system; 12 is a capstan drive system circuit (not shown) that drives a capstan;
13 is a video signal output terminal.

Signals reproduced from the rotating magnetic head of the rotating head drum 5 are supplied to a reproduction amplifier 6. At this time, assuming a two-head helical scan type VTR, for example, the reproduction signal input to the reproduction amplifier has already been converted into a continuous signal by a head changeover switch (not shown). The signal amplified by the reproduction amplifier is sent to a video signal processing circuit 7 and a filter amplifier 8.
．． 9 respectively.

As is well known, the video signal processing circuit 7 restores the reproduced video signal to its original signal form and outputs it from the output terminal 13.

The switch 10 is connected to the A side if the tape 4 in the cassette 1 is an MP tape, and to the B side if the tape 4 in the cassette 1 is an ME tape, according to the above-mentioned detection signal, and the filter amplifier 8.9 outputs a pilot signal suitable for each tape. Outputs a filtered and amplified signal. The pilot signal output from this switch 10 is supplied to a tracking signal processing circuit 11, and the circuit 11 outputs a tracking control signal through well-known signal processing using a four-frequency system. This tracking control l@ number is supplied to the capstan drive system circuit 12, and the circuit 12 controls the running of the tape so that the rotary head accurately tracks the tape 4 from 1 to 1 on the basis of this tracking control signal. do.

FIG. 2 is a diagram showing a specific example of the configuration around the filter amplifiers 8 and 9, and the same numbers as in FIG. 1 indicate the same components.
is a bandpass filter (BPF), and 8b and 9b are amplifiers, respectively. Note that 8a and 8b are 8 and 9a in FIG.

9b corresponds to 9 in FIG. 1, respectively.

Since the reproduction level of the low frequency range of the ME tape is lower than that of the MP tape, the gain of the amplifier 9b is set larger than that of the amplifier 8b. Furthermore, since the gain of the amplifier 9b increases, low frequency noise also increases. LPF
8a is the frequency of four pilot signals fl, f2 . f3
It has a cutoff frequency slightly higher than the highest frequency of ゜f4, but when this LPF8a is used during playback from ME tape, noise components lower than the lowest frequency of the four pilot signals will be greatly amplified. , BPF 9a is configured to filter only the frequency band of the pilot signal. Also LPF8a and BPF9
a is set so that the filtering characteristics within the frequency band of the pilot signal between the reproduced signal from the ME tape and the reproduced signal from the MP tape differ depending on the difference in frequency characteristics within the frequency band. This causes fl, f2. f3. There is no problem that the reproduction level differs when one tape is reproduced due to the difference in the frequency of f4.

In the 4J 4-wave system, the levels of two types of pilot signals reproduced from the adjacent 1-racks on both sides of the reproduced track are compared, so if the reproduction level differs depending on the frequency, tracking accuracy will deteriorate, but this is true. The device of the embodiment can also prevent such a situation.

FIG. 3 is a diagram showing a schematic configuration of a reproduction system of a VTR as another embodiment of the present invention, in which the same components as in FIG. 1 are designated by the same numbers and detailed explanations are omitted.

In the figure, 18 is a filter amplifier to which the output of the regenerative amplifier is supplied, 19 is a group of elements for determining the characteristics of the filter amplifier 18, and 20 is a filter amplifier that converts the characteristic element group 19 based on the detection signal from the detection device. This is a switch circuit selectively connected to 18. By the action of this switch circuit 20, the characteristics of the filter amplifier 18 are switched depending on whether the tape 4 is an MP tape or an ME tape. That is, for example, in the case of ME tape, the amplification gain is increased and the filtering cutoff frequency is set strictly.

The embodiment of FIG. 3 also has the advantage that the same effect as that of FIG. 1 can be obtained, and the circuit scale can be further reduced.

[Effects of the Invention] As described above, according to the present invention, excellent tracking control can be performed no matter when reproducing any of a plurality of types of recording media having different characteristics.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a reproduction system of a VTR as an embodiment of the present invention, FIG. 2 is a diagram showing a specific configuration example around the filter and amplifier in FIG. 1, and FIG. FIG. 3 is a diagram showing a schematic configuration of a reproduction system of a VTR as another embodiment of the present invention. 1 is a cassette, 2 is a detection hole, 3 is a detection device as a discrimination means, 4 is a magnetic tape as a recording medium, 5 is a rotary head drum having a rotary playback head, 7 is a video signal processing circuit, 8 and 9 are 11 is a tracking signal processing circuit in the pilot signal processing means, 12 is a capstan drive system circuit as a control means, and 18 is a filter in the pilot signal processing means. - An amplifier, 19 a characteristic element group, and 20 a switch circuit as a switching means.

Claims (1)

[Scope of Claims] (1) A device for reproducing an information signal from a recording medium in which a tracking control pilot signal is recorded together with the information signal, comprising: a determining means for determining the type of the recording medium; and the recording medium. a reproduction head for reproducing the information signal from the medium; a pilot signal processing means for forming a tracking control signal using the pilot signal reproduced from the recording medium; and a reproduction head for reproducing the information signal from the recording medium based on the tracking control signal. An information signal reproducing device comprising: control means for controlling relative positions of media; and switching means for switching signal processing characteristics of the pilot signal processing means based on the determination result of the determination means. (2) The discriminating means is capable of discriminating whether the recording medium is formed by coating a metal magnetic material or by depositing a metal alloy magnetic material, and the information signal and the pilot signal are frequency multiplexed on the recording medium. An information signal reproducing device according to claim (1), characterized in that: (3) The information signal reproducing apparatus according to claim (2), wherein the pilot signal processing means includes an amplifier for amplifying the reproduced pilot signal, and the switching means switches the gain of the amplifier. (4) The pilot signal processing means includes a filter that separates the pilot signal from the reproduction signal of the reproduction head, and the switching means switches the frequency range filtered by the filter. 2) The information signal reproducing device described in section 2).