JPH0212603A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To always attain excellent recording at an optimum level by discriminating the optimum recording level corresponding to the characteristic of a magnetic tape to be used, and executing the recording at the discriminated level. CONSTITUTION:Based on the output voltage of an envelope detecting circuit 12 to detect the envelope of a regenerative signal at a part recorded at the plural levels, the optimum recording level is discriminated, and a recording amplifier 5 is controlled so as to hold the discriminated optimum recording level. That is, when the recording is executed by using the magnetic tape having a certain characteristic, the recording is executed at the plural levels on one part of the magnetic tape, based on the envelope detected from the regenerative signal on the recording part at the plural levels, the optimum recording level conforming to the characteristic of the magnetic tape to be used is discriminated and the recording amplifier 5 is controlled so as to hold the discriminated recording level. Thus, the optimum recording is always attained regardless of the characteristic of the magnetic tape to be used.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording and reproducing device equipped with an automatic tracking control device that performs tracking control using, for example, an output voltage of an envelope detection circuit that detects the envelope of a reproduced signal. The present invention is applied to VTRs such as M (hereinafter referred to as VTRs), and is designed to perform recording in accordance with the characteristics of the magnetic tapes used.

[Prior art] Figure 3 shows a conventional VT that enjoys an automatic tracking side control device.
It is a block diagram showing the configuration of R, and in the same figure, (2
) is the recording system luminance signal processing circuit, (3) is the FM modulator, (
4) is a recording equalizer, and the input video signal (1)
(5) is a recording amplifier, (8) is a rotary transformer, and (7) is a magnetic video head, which performs FM modulation on the luminance signal and corrects the frequency characteristics of the FM video signal. This is a circuit configuration of a recording system that records 0 or more on a magnetic tape (6).

(9) is a video signal head amplifier, and (lO) is a reproduction system luminance signal processing circuit, which demodulates the FM video signal reproduced from the magnetic tape (6) via the magnetic video head (7) and restores the original signal. A video signal (11) is output. (1
2) is an envelope detection circuit that detects the envelope of the reproduced FM video signal. (+3) is an A/D conversion circuit, (14) is a memory circuit, (15) is an optimum tracking amount calculation processing circuit, and (1B) is a mechanical control circuit. Based on the output voltage of the envelope detection circuit (12), By calculating the optimal tracking acid and performing mechanical control,
0 and above are the circuit configurations of the reproduction system that perform automatic optimal tracking control.

Next, the operation of the above configuration will be explained.

In the recording mode, the recording system luminance signal processing circuit (2),
The FM video signal that has passed through the FM modulator (3) is corrected by the recording equalizer (4) to cut the signal below about 1111 Hz in order to be mixed with the chroma signal later. Recording amplifier (5)
, a rotary transformer (8), and a magnetic video head (7) to record on a magnetic tape (6).

In addition, in the playback mode, the FM video signal played from the magnetic tape (6) by the magnetic video head ()) passes through the head amplifier (9) and then passes through the playback system luminance signal processing circuit (1).
0), where it is demodulated and output as the original video signal (11). At this time, the envelope of the reproduced FM video signal output from the head amplifier (9) is detected by the envelope detection circuit (12), and the output voltage is A/D converted and stored in memory. Automatic optimal tracking control is performed by calculating the tracking field and operating the mechanical control circuit (16).

[51, Problems to be Solved by Akira] Since the conventional VTR is configured as described above, recording is always performed at a constant level in the recording mode, regardless of the characteristics of the magnetic tape used. Therefore, when magnetic tapes with various characteristics are used randomly, it is not always possible to perform optimal recording that matches the characteristics of the tape used, and as a result, the recording level varies depending on the tape used. There was a problem.

This invention was made to solve the above-mentioned problems, and when stretching @W tape with any characteristics ≠
), an object of the present invention is to provide a VTR that can always record at an optimal level according to the characteristics of the tape used.

[Means for Solving the Problems] A VTR according to the present invention determines the optimum recording level based on the output voltage of an envelope detection circuit that detects the envelope of a reproduced signal of a portion recorded at a plurality of levels. The present invention is characterized in that the recording amplifier is controlled so as to maintain the determined optimum recording level.

[Operation] According to the present invention, when recording is performed using a magnetic tape with a certain characteristic, first, the I? of the magnetic tape is determined. Recording is performed at multiple levels in the B portion, and based on the envelope detected from the reproduced signal of the recorded portion of the multiple levels, the optimal recording level that matches the characteristics of the magnetic tape to be used is determined, and the determined level is determined. By controlling the recording amplifier so as to maintain the recorded level, optimum recording can always be performed regardless of the characteristics of the magnetic tape used.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a VTR equipped with an automatic optimal tracking control device according to an embodiment of the present invention, in which (1) to (16) are the same as the conventional example shown in FIG. , therefore, the same reference numerals are given and detailed explanation thereof will be omitted.

In FIG. 1, (17) is an optimum recording current calculation processing circuit, and this optimum recording current calculation processing circuit (17) calculates the recording level at which the envelope value digitized by the A/D conversion circuit (13) is maximum. A microcomputer is generally used to determine the voltage and create a control voltage. (18) is a recording current control circuit (hereinafter referred to as electronic volume), and the optimum recording current calculation processing circuit (17)
The gain of the recording amplifier (5) is controlled in response to the control voltage output from the recording amplifier (5).

Next, the operation of the above configuration will be explained.

Note that since the automatic optimal tracking control operation is the same as described in the conventional example, the description thereof will be omitted.

FIG. 2 is a flowchart showing the control operation of the microcomputer constituting the optimum recording current arithmetic processing circuit (17), in which a represents a standard recording level setting value and b represents a certain level.

First, when you enter the automatic optimum recording level setting mode, the VT
R automatically enters the recording mode (step 100), and the level is 2b lower than the standard recording level a, that is, a-2b.
Recording starts at a level of (step 101), and then the recording starts at a level b lower than the standard recording level a, that is, a
Recording at level -b (step 102), recording at standard level a (step 103), recording at level b higher than standard recording level a, that is, recording at level a+b (
Step 104), recording at a level 2b higher than the standard recording level a, that is, a+2b level (step 10
5) is performed one after another. Each of these steps to
The recording time of i-tos is about 3 seconds each, and the recorded parts at each level are (view), (-), (b),
(o) and (p). In order to vary the recording level, the microcomputer outputs a recording level control voltage to control the gain of the recording amplifier (5) via the electronic volume (18). This is achieved by

Next, step 106) stops the recording mode.
Rewind the recorded tape portion to the recording start point (step 107)L, then playback (step 10)
8) During this playback, 1. E2 each part (cross), (m
), (n), (o), and (p) are detected by the envelope detection circuit (12), and the output voltage is digitized and stored in the memory circuit (14).Step 109) Recorded part (cross) ~ (p)
When the reproduction of is completed, the maximum value among the above (!L) to (p) is determined (step 110).By determining the part corresponding to the maximum value determined in this way, (Step l1l), the recording level of that portion becomes the optimum recording level for the magnetic tape (6) to be used.

Next, a control voltage corresponding to the optimum recording level is outputted via the electronic volume (18) (step 112).
), by controlling the gain of the recording amplifier (5), recording can be performed at the optimum recording level that matches the characteristics of the magnetic tape (6).

It should be noted that in the above embodiments, an explanation has been given of an application to a VTR equipped with an automatic tracking control device. In this case, the envelope detection circuit in the automatic tracking control device can be used for automatically setting the optimum recording level, but the same effects as in the above embodiment can be obtained even when applied to a VTR without an automatic tracking control device.

In addition, if the above operation is performed every time a magnetic tape is inserted, it will take time to start recording, so it is necessary to memorize the optimal recording level set for multiple magnetic tapes with different characteristics. If it is configured to selectively read and control it depending on the magnetic tape used, -layer VT
Convenient for using R.

[Effects of the Invention] As described above, according to the present invention, it is possible to determine the optimum recording level according to the characteristics of the magnetic tape used, and to perform automatic control to perform recording at the determined level. Therefore, no matter what kind of magnetic tape is used, good recording can always be performed at the optimum level.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a VTR according to an embodiment of the present invention, FIG. 2 is a flowchart explaining aS production, and FIG. 3 is a block diagram showing the configuration of a conventional VTR. (5)... Recording amplifier, (12)... Envelope detection circuit, (14)... Memory circuit, (17)...
Optimal recording current calculation processing circuit, 08) Recording current control circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) An envelope detection circuit that detects the envelope of the playback signal of the portion recorded at multiple levels,
means for determining the optimum recording level based on the output voltages corresponding to the plurality of recording levels of the envelope detection circuit; means for holding the control voltage corresponding to the determined optimum recording level; 1. A magnetic recording/reproducing device comprising means for controlling a recording amplifier to maintain an optimum recording level using a control voltage.