JP2000207703A - Playback apparatus, method and computer readable storage medium - Google Patents

Abstract

(57) Abstract: In a reproducing apparatus having a plurality of heads, a cut-off frequency of a filter for removing noise of a control voltage of an equalizer circuit is lowered to obtain a sufficient noise suppressing effect. SOLUTION: Reproduction signals of heads 10 and 20 are switched by a switch 13 controlled by a switching signal a via head amplifiers 11 and 12, and a peaking amount is controlled by a control voltage d by a variable peaking circuit 15 of a variable equalizer 14. Controlled. As the control voltage d, the control voltage V ₁ or V ₂ selected by the changeover switch 19 controlled by the changeover signal b is obtained through the LPF 21. The control unit 18 sets the switching point of the switching signal b to:
The control is performed so as to coincide with, for example, the end point of the reproduction signal envelope before the switching point of the switching signal a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus and method suitable for use in a magnetic recording / reproducing apparatus having a plurality of heads such as a VTR, and a computer-readable storage medium used for the apparatus and method.

[0002]

2. Description of the Related Art FIG. 6 shows a configuration of a conventional reproducing apparatus such as a VTR having two rotary heads. In FIG. 6, reproduced signals alternately reproduced by the heads 10 and 20 from a magnetic tape (not shown) are amplified by the head amplifier 13 and then alternately switched by the switch 13 to be input to the variable equalizer 14. After the peaking amount is varied according to each head by the variable peaking circuit 15 in the variable equalizer 14, the variable delay circuit 16 varies the delay amount according to each head. The output signal c of the variable equalizer 14 is subjected to A / D conversion, signal processing, D / A conversion, and the like by a digital signal processing circuit 17 to obtain a reproduced video signal.

The switch 13 is switched by a head amplifier switching signal a from a control unit 18 using a microcomputer or the like. The control unit 18 switches the switch 19 to select the control voltages V ₁ and V _{2 according} to each head. The selected voltage is noise-suppressed by the LPF (low-pass filter) 21 and the control voltage d 1
And the amount of peaking of the variable peaking circuit 15 is controlled.

The control unit 18 switches the switch 22 to select the control voltages V ₃ and V _{4 according} to each head, and the selected voltage is noise-suppressed by the LPF 23 to become the control voltage e. , The delay amount of the variable delay circuit 16 is controlled. The switches 19, 22
Is the switch 1 by the head amplifier switching signal a.
3 is switched.

FIG. 7 shows the head amplifier switching signal a,
The timing of the control voltage d and the envelope C of the reproduction signal is shown. As shown, the switching signal a
And the control voltage d match.

[0006]

However, in the above conventional example, when the cutoff frequency of the LPF is lowered and the voltage waveform of the control signal is blunted, the control voltage d shown in FIG.
As shown in the waveform (1), the rising of the waveform is applied to the intrusion of the actual reproduction envelope C, so that the cutoff frequency of the LPF cannot be lowered. For this reason, there is a problem that the noise suppression effect is reduced. Further, if the cutoff frequency of the LPF is forcibly lowered, there arises a problem that the peaking characteristics and the delay characteristics of the inrush portion of the envelope do not match.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has a low cut-off frequency of an LPF for removing noise from a control voltage so that signal processing with lower noise can be performed. It is intended to be.

[0008]

In order to achieve the above object, in a reproducing apparatus according to the present invention, a plurality of heads for reproducing a recording medium and one of the reproduced signals from the plurality of heads are used. Means for selecting the selected signal by a first selection signal, equalizer means for controlling the characteristics of the selected reproduced signal by a control signal corresponding to the corresponding head means, and a plurality of control signals for controlling the equalizer means. Generating means, a second selecting means for selecting one of the plurality of control signals by a second selecting signal in accordance with the selection of the first selecting means, and Low-pass filter means for passing the signal to the equalizer means for generating the first and second selection signals, wherein the start point of the second selection signal is determined by the switching of the first selection signal; It is provided and control means for generating as a pre-changed points.

In the reproducing method according to the present invention,
A step of selecting one of the reproduction signals of a plurality of head means for reproducing the recording medium by a first selection signal, and an equalizer process for controlling the characteristics of the selected reproduction signal by a control signal corresponding to the corresponding head means. A step of selecting one of a plurality of control signals by a second selection signal in accordance with the selection by the first selection signal; and a step of removing a low band of the selected control signal. Generating the first and second selection signals, wherein the start point of the second selection signal is generated before the switching point of the first selection signal. .

In the storage medium according to the present invention,
A step of selecting one of the reproduction signals of a plurality of head means for reproducing the recording medium by a first selection signal, and an equalizer process for controlling the characteristics of the selected reproduction signal by a control signal corresponding to the corresponding head means. Processing, generating a plurality of control signals, selecting one of the plurality of control signals by a second selection signal in accordance with selection by the first selection signal, A process of removing the low frequency band of the control signal, and generating the first and second selection signals, wherein the start point of the second selection signal is before the switching point of the first selection signal. And a program for executing the processing that occurs as follows.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the reproducing apparatus according to the present invention.
An embodiment will be described. In FIG. 1, portions substantially equivalent to those in FIG. 6 are denoted by the same reference numerals, and redundant description is omitted. In FIG. 1, the control unit 18 outputs a control voltage switching signal b for switching the switches 19 and 22 as second selecting means. still,
The head amplifier switch 13 constitutes a first selecting means.

FIG. 2 is a graph showing the operation of the variable peaking circuit 15, and shows that the peaking amount can be varied by changing the control voltage d.

The control voltage d is obtained by selecting a voltage corresponding to each head by the control voltage changeover switch 19, suppressing the selected voltage with a LPF 21, and inputting it to the variable peaking circuit 15. The output of the variable peaking circuit 15 is input to a variable delay circuit 16. The control voltage e controls the delay amount corresponding to each head.

FIG. 3 is a graph showing the operation of the variable delay circuit 16, and by changing the control voltage e,
This indicates that the delay amount is variable.

The control voltage e is obtained by selecting a voltage corresponding to each head by the control voltage changeover switch 22 and suppressing the selected voltage with the LPF 23 for noise, and input to the variable delay circuit 16. The output of the variable delay circuit 16 is input to the digital signal processing circuit 17 and processed to obtain a reproduced video signal.

FIG. 4 shows the timing of a head switching signal a as a first selection signal, a control voltage switching signal b as a second selection signal, a control voltage d, and an envelope C of a reproduction signal. As shown in the figure, the rising edge, which is the switching point of the control voltage switching signal b, coincides with the end point of the envelope C, and is before the rising edge, which is the switching point of the head switching signal a. Thus, even if the cutoff frequency of the LPF 21 is lowered and the waveform of the control voltage d is blunted, it does not affect the actual reproduction envelope.

Therefore, the noise suppression effect of the LPF 21 can be sufficiently obtained, and the variable peaking circuit 15 can perform good peaking amount control. still,
The switching point of the control switching signal b may be between the end point of the envelope C and the point before the switching point of the head switching signal a.

FIG. 5 shows a second embodiment of the reproducing apparatus according to the present invention, in which a head 30 is added to the first embodiment of FIG. 1 to form a three-head configuration. ing. With the addition of this head 30, a head amplifier 31, a head amplifier selector switch 32, the control voltage selector switch 33, 34 and the control voltage V _5,
V ₆ and the like are newly provided. Further, the control section 18 outputs a head amplifier switching signal a 'and a control voltage switching signal b'.

The outputs of the three head amplifiers 11, 12 and 31 are sequentially switched by switches 13 and 32, input to a variable equalizer circuit 14, and processed in the same manner as in the first embodiment. Further, control voltages corresponding to the respective heads are appropriately selected by the switches 19, 33, 22, and 34 and input to the LPFs 21 and 23 to obtain control voltages d and e.

In this case, the rise of the control voltage switching signal b 'coincides with the end point of the envelope C of the reproduction signal, and the rising of the head switching signal a, similarly to the control voltage switching signal b of FIG. There is. Thus, even if the cutoff frequency of the LPF 21 is lowered and the waveform of the control voltage d is blunted, it does not affect the actual reproduction envelope.

Therefore, according to the present embodiment, even if the number of heads is increased, the noise suppressing effect of the LPF 21 can be sufficiently obtained as in the first embodiment, and the variable peaking circuit 15 has a good noise suppression effect. Peaking amount control can be performed.

Next, a storage medium according to another embodiment of the present invention will be described. The present invention can be realized by a hardware configuration, but can also be realized by being configured in a computer system including a CPU and a memory. When configured in a computer system, the memory forms a storage medium according to the present invention. That is, a storage medium storing a program code of software for executing the operation described in each of the above-described embodiments is used in a system or an apparatus, and the CPU of the system or apparatus executes the program code stored in the storage medium. By reading and executing, the object of the present invention can be achieved.

As the storage medium, ROM, R
Semiconductor memory such as AM, optical disk, magneto-optical disk,
A magnetic medium or the like may be used, and these may be configured and used in a CD-ROM, a floppy disk, a magnetic tape, a magnetic card, a nonvolatile memory card, or the like.

Therefore, this storage medium is used in a system or apparatus other than the system or apparatus shown in FIGS. 1 and 5, and the system or computer reads out and executes the program code stored in this storage medium. Accordingly, the same functions as those of the above embodiments can be realized, the same effects can be obtained, and the object of the present invention can be achieved.

An OS running on the computer
When performing part or all of the processing, or after the program code read from the storage medium is written to a memory provided in an extended function board or an extended function unit connected to the computer, Even when the CPU or the like provided in the above-mentioned extended function board or extended function unit performs a part or all of the processing based on the instruction of the program code, the same functions as those of the above embodiments can be realized and the same functions can be realized. Effect can be obtained,
The object of the present invention can be achieved.

[0026]

As described above, according to the present invention, the cut-off frequency of the LPF for removing noise of the control voltage for controlling the equalizer means can be lowered, and a better signal processing with lower noise can be achieved. It can be carried out.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a reproducing apparatus according to the present invention.

FIG. 2 is a graph showing an operation of the variable peaking circuit according to the first embodiment of the present invention.

FIG. 3 is a graph showing an operation of the variable delay circuit according to the first embodiment of the present invention.

FIG. 4 is a timing chart showing the operation of the first exemplary embodiment of the present invention.

FIG. 5 is a configuration diagram showing a second embodiment of the reproducing apparatus according to the present invention.

FIG. 6 is a configuration diagram showing a conventional playback device.

FIG. 7 is a timing chart showing an operation of a conventional reproducing apparatus.

[Explanation of symbols]

10, 20, 30 head 11, 12, 31 head amplifier 13, 32 head amplifier changeover switch 14 variable equalizer circuit 15 variable peaking circuit 18 control unit 19, 22, 33, 34 control voltage changeover switch 21 LPF a, a 'head amplifier switching signal b, b 'control voltage switching signal d controls a voltage V ₁ ~V ₆ control voltage

Claims (5)

[Claims] A plurality of head means for reproducing a recording medium;
Selecting means for selecting with the selection signal of the above, equalizer means for controlling the characteristics of the selected reproduction signal by a control signal corresponding to the corresponding head means, and generating a plurality of control signals for controlling the equalizer means. Generating means, second selecting means for selecting one of the plurality of control signals by a second selection signal according to the selection of the first selecting means, and passing the selected control signal Low-pass filter means for applying to the equalizer means, and generating the first and second selection signals,
And a control means for generating a start point of the selection signal of (i) before the switching point of the first selection signal. 2. The control unit according to claim 1, wherein a start point of the second selection signal is a position corresponding to an end point of the selected reproduction signal or a switching point between the end point and the first selection signal. 2. The reproducing apparatus according to claim 1, wherein the signal is generated so as to be located between the front and the front. 3. The reproducing apparatus according to claim 1, wherein said equalizer means includes amplitude control means for controlling an amplitude characteristic of said reproduction signal. 4. A procedure for selecting one of the reproduced signals of a plurality of head means for reproducing a recording medium from a plurality of reproduced signals by a first selection signal, and selecting a characteristic of the selected reproduced signal according to the corresponding head means. A procedure of performing an equalizer process by a control signal, a procedure of selecting one of a plurality of control signals by a second selection signal in accordance with a selection by the first selection signal, and a procedure of selecting a low band of the selected control signal. Removing, and generating the first and second selection signals,
Wherein the start point of the selection signal is generated before the switching point of the first selection signal. 5. A process for selecting one of the reproduction signals of a plurality of head means for reproducing a recording medium from a plurality of reproduction signals by a first selection signal, and adjusting a characteristic of the selected reproduction signal according to the corresponding head means. A process of performing an equalizer process by a control signal; a process of generating a plurality of control signals; and a process of selecting one of the plurality of control signals by a second selection signal in accordance with the selection by the first selection signal. Removing the low frequency band of the selected control signal; generating the first and second selection signals;
A computer-readable storage medium storing a program for executing a process that is performed so that the start point of the selection signal is before the switching point of the first selection signal.