JP2547822B2 - Information signal reproduction device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an information signal reproducing apparatus, and more particularly to an apparatus for reproducing the information signal from a recording medium on which a tracking control pilot signal is recorded together with the information signal. is there.

[Prior Art] Conventionally, a method is known in which a plurality of types of pilot signals of a predetermined frequency are recorded together with an information signal during recording, and tracking control is performed based on the reproduction level of the pilot signal during reproduction. For example, a four-frequency system in a consumer video tape recorder (VTR) corresponds to the above method.

The level of the reproduced pilot signal differs depending on the type of recording medium even if the recording level is the same. A conventional reproducing apparatus is generally provided with an automatic gain control (AGC) circuit, and this AGC circuit compensates for the difference in the reproducing level.

[Problems to be Solved by the Invention] However, when signals are recorded on a plurality of types of recording media having greatly different characteristics with the same format, it becomes impossible to compensate for the difference in the reproduction level of the pilot signal, and either In some cases, good tracking cannot be performed when the signal is reproduced from the recording medium.

For example, in a VTR that performs tracking control of a four-frequency system, a video signal and four types of pilot signals with the same recording level on a metal-coated tape (hereinafter referred to as MP tape) and a metal-evaporated tape (hereinafter referred to as ME tape) with the same format In a recordable system, the reproduction signal level in the low frequency range of the ME tape becomes much smaller than that of the MP tape and the S / N also deteriorates. In this case, if the pilot signal processing circuit for the MP tape is used, it may not be possible to perform tracking control using the pilot signal reproduced from the ME tape. This is because not only the reproduction level is low, but also the low-frequency noise component increases due to the action of the AGC circuit.

Under the above-mentioned object, the present invention has an advantage in that when the information signal and the tracking control signal are recorded in the same format on recording media having different characteristics, whichever recording medium is reproduced. 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, the information signal reproducing apparatus of the present invention is an apparatus for reproducing the information signal from the recording medium on which the tracking control pilot signal is recorded together with the information signal. A discriminating means for discriminating the type of the recording medium, a reproducing head, a reproducing means for reproducing the information signal from a signal reproduced from the recording medium by the reproducing head, and a reproducing means provided in parallel. Pilot signal processing means for forming a tracking control signal by using the pilot signal reproduced from the recording medium by the reproducing head, and controlling relative positions of the reproducing head and the recording medium based on the tracking control signal. Control means for
A switching means is provided for switching the signal processing characteristics of the pilot signal processing means based on the determination result of the determination means.

[Operation] With the configuration described above, the signal processing characteristics of the pilot signal processing means can be switched according to the recording medium on which the pilot signal is being reproduced, and the processing characteristics suitable for the recording medium can be set. Good tracking control can be realized when reproducing the information signal from any of the various recording media.

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

FIG. 1 is a diagram showing a schematic structure of a reproducing system of a VTR as an embodiment of the present invention. In the figure, 1 is a cassette containing a magnetic tape, and 2 is a detection hole provided in a housing of the cassette 1. , The magnetic tape stored in the cassette 1 depends on whether the detection hole 2 is open or closed.
Indicates whether it is an MP tape or an ME tape. A detection device 3 mechanically detects 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 rotary head drum having a rotary magnetic head near the outer periphery, 6 is a reproduction amplifier, 7 is a video signal processing circuit, 8 is an MP tape filter and amplifier, and 9 is a ME tape filter and amplifier. , 10 is a switch that can be switched according to the detection signal, 11 is a well-known tracking signal processing circuit of a 4-frequency system, 12 is a capstan drive system circuit for driving a capstan (not shown), and 13 is a video signal output terminal.

The signal reproduced from the rotating magnetic head of the rotating head drum 5 is supplied to the reproducing amplifier 6. At this time, for example, assuming a 2-head helical scan type VTR, the reproduction signal input to the reproduction amplifier is already a continuous signal by a head switching switch (not shown). The signal amplified by the reproduction amplifier is the video signal processing circuit 7, the filter amplifier 8,
Input in 9 respectively.

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

The switch 10 is on the A side when the tape 4 in the cassette 1 is an MP tape according to the above-mentioned detection signal, and is B when the tape is an ME tape.
The filter amplifiers 8 and 9 are connected to the output side and output the signals obtained by filtering and amplifying the pilot signals suitable for the respective tapes. The pilot signal output from the switch 10 is supplied to the tracking signal processing circuit 11,
The circuit 11 outputs a tracking control signal by well-known signal processing in the 4-frequency system. This tracking control signal is supplied to the capstan drive system circuit 12, which on the basis of this tracking control signal causes the rotary head to move to tape 4.
Control the tape travel to accurately trace the above tracking.

FIG. 2 is a diagram showing a specific configuration example around the filter amplifiers 8 and 9, and the same reference numerals as those in FIG. 1 indicate the same components. In the figure, 8a is a low-pass filter (LPE), 9a is a band-pass filter (BPF), and 8b and 9b are amplifiers.
Incidentally, 8a and 8b correspond to 8 in FIG. 1, and 9a and 9b correspond to 9 in FIG. Since the ME tape has a lower reproduction level in the low frequency range than the MP tape, the gain of the amplifier 9b is set to be larger than that of the amplifier 8b. Further, since the gain of the amplifier 9b increases, the low frequency noise also increases. LPF8
a has a cut-off frequency slightly higher than the highest frequency of four pilot signals f1, f2, f3, f4, but when this LPF8a is used during playback from ME tape,
A low-frequency noise component is amplified more than the lowest frequency of the two pilot signals. Therefore, the BPF 9a is configured to filter only the frequency band of the pilot signal. LPF8a and BPF9a are the playback signal from the ME tape and the MP
The filtering characteristic in the frequency band of the reproduction signal from the tape is set to be different depending on the difference in the frequency characteristic of the pilot signal in the frequency band. As a result, there is no problem that the reproduction level is different when reproducing one of the tapes due to the difference in frequency of f1, f2, f3 and f4. In the four-frequency system, since the levels of two types of pilot signals reproduced from both adjacent tracks of the reproduction track are compared, if the reproduction level differs depending on the frequency, the tracking accuracy deteriorates. The above device can prevent such a situation.

FIG. 3 is a diagram showing a schematic configuration of a VTR reproducing system as another embodiment of the present invention. In the figure, the same components as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

In the figure, 18 is a filter amplifier to which the output of the reproduction amplifier is supplied, 19 is an element group for determining the characteristics of the filter amplifier 18, 20 is a filter amplifier for the characteristic element group 19 based on the detection signal from the detection device. A switch circuit selectively connected to 18. By the action of this switch circuit 20, the tape 4
Filter amplifier for both MP tape and ME tape
Switching 18 characteristics. That is, for example, in the case of a ME tape, the amplification gain is increased and the cut-off frequency for filtering is set strictly.

The embodiment shown in FIG. 3 has the advantages that the same effects as those shown in 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, good tracking control can be performed regardless of which of a plurality of types of recording media having different characteristics is reproduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a VTR reproduction system as an embodiment of the present invention, FIG. 2 is a diagram showing a concrete configuration example of the periphery of the filter amplifier shown in FIG. 1, and FIG. It is a figure which shows schematic structure of the reproduction | regeneration system of VTR as another Example of this invention. 1 is a cassette, 2 is a detection hole, 3 is a detection device as a discriminating means, 4 is a magnetic tape as a recording medium, 5 is a rotary head drum having a rotary reproduction head, 7 is a video signal processing circuit, and 8 and 9 are respectively A filter and an amplifier in the pilot signal processing means, 10 a switching means, 11 a tracking signal processing circuit in the pilot signal processing means, 12 a capstan drive system circuit as a control means, 18 a filter amplifier in the pilot signal processing means , 19 are characteristic element groups, and 20 is a switch circuit as switching means.

Claims (4)

(57) [Claims] 1. 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, the device comprising a judging means for judging the type of the recording medium, a reproducing head, and the reproducing device. A reproducing means for reproducing the information signal from a signal reproduced from the recording medium by a head, and a tracking control signal using the pilot signal provided in parallel with the reproducing means and reproduced from the recording medium by the reproducing head. An information signal reproducing apparatus comprising: a pilot signal processing unit that forms a signal, and a switching unit that switches a signal processing characteristic of the pilot signal processing unit based on a determination result of the determination unit. 2. The discriminating means is capable of discriminating whether the recording medium is formed by coating a metal magnetic material or vapor deposition of a metal magnetic material, and the information signal and the pilot signal are frequency-multiplexed on the recording medium. The information signal reproducing apparatus according to claim (1), which is recorded and recorded. 3. The information signal reproducing apparatus according to claim 2, wherein the pilot signal processing means includes an amplifier for amplifying a reproduction pilot signal, and the switching means switches a gain of the amplifier. apparatus. 4. The pilot signal processing means includes a filter for separating the pilot signal from the reproduction signal of the reproduction head, and the switching means switches the frequency range to be filtered by the filter. In the range (2), the information signal reproducing apparatus is described.