JPS58143406A - Method for setting automatic sound recording of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To set an optimum sound recording bias value in a short time by varying resolution in accordance with the kind of a magnetic tape and deciding on an irreducible necessary overall variable bias range. CONSTITUTION:The titled method is referred to a test for setting the recording bias value while the resolution in the overall variable bias range for all kind of magnetic tapes is divided into 16 steps. For a normal magnetic tape, when the 10th step is regarded as the optimum sound recording bias value, variation in sound recording bias value due to the difference of one magnetic tape from another is a little, so the overall variable bias range is narrowed down by changing the number of steps of the resolution in the variable bias range T1 to 8 steps to set the 6th step as the optimum sound recording bias value as shown in a figure (b). Namely, the time necessary for a test with 8 steps is shortened as compared with a figure (a), and the time required to set the optimum sound recording bias value of normal magnetic tapes is shortened greatly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an automatic magnetic recording and reproducing apparatus for a magnetic recording and reproducing apparatus such as a tape recorder, which is capable of automatically and quickly setting the amount of recording bias applied to a magnetic tape. Concerning how to set up recording.

Magnetic recording of audio signals in a tape recorder requires low distortion over a wide band and a wide dynamic range. When an audio signal is recorded on a magnetic tape as a recording medium, a bias current (high frequency current) 1&: is superimposed on the signal current to avoid the nonlinearity of the magnetic tape. In tape recorders, choosing where to set the bias current described above is an additional problem. By the way, the optimum recording bias current size varies depending on the type of magnetic tape (normal tape, ferrichrome tape, chrome tape, metal tape, etc.), and also depending on the rank of the same type of magnetic tape. Therefore, when different types of magnetic tapes are used while keeping the above-mentioned recording bias current level constant (fixed) in a tape recorder, the optimum characteristics of each magnetic tape cannot be obtained. It's something that doesn't exist. That is, in magnetic recording and reproduction in a tape recorder, it is necessary to set an optimal recording bias current that takes into account the characteristics VC of each magnetic tape described above. 3. When setting the recording bias value, the optimal recording bias value is detected. Some common methods include:

(1) A method of varying the recording bias amount as a parameter and setting the recording bias value at a point where the recording playback level becomes flat between the reference frequency and the high frequency.

(2) Vary the recording bias amount to determine the point at which the recording playback level at a certain reference frequency peaks,
A method of determining the optimum value as a recording bias value from this point.

Note that the above-described variation in the amount of recording bias means that the recording bias is divided into steps (resolution) within a certain variable range. Usually, the resolution within the variable range of the recording bias described above is not changed depending on the type of magnetic tape used. Regardless of the type of magnetic tape used,
All the above resolutions are the same. Therefore, no matter what type of magnetic tape is used, the time required to set the recording bias value is the same.

The present invention focuses on the fact that there is little change in the appropriate recording bias amount for the same type of magnetic tape (for example, normal tape type, metal tape type, etc.), and changes the resolution depending on the type of magnetic tape used. An object of the present invention is to provide an automatic recording setting method for a magnetic recording/reproducing device, which can set an optimal recording bias value within a short time while minimizing the bias variable range.

An embodiment of the method according to the present invention will be described below.

FIG. 1 shows the case where a test is carried out to set the recording bias value for all types of magnetic tapes, with the resolution in the entire bias variable range T set at 16 steps. However, for normal magnetic tapes, if the 10th step shown in the figure is set to the optimum recording bias amount, there is not much change in the recording bias amount due to differences in individual magnetic tapes, so as shown in Figure 2. Next, the resolution in the bias variable range TI is changed to 8 steps, the entire bias variable range is narrowed, and the 6th step shown in the figure is set as the optimal recording bias value.

In other words, compared to the case shown in Figure 1, the time required for testing 8 steps can be saved, and the time required to set the optimal recording bias value for normal magnetic tape can be saved. can be shortened as much as possible.

For chromium-based and metal-based magnetic tapes, the resolution in the variable bias range T is tested at 16 steps as shown in FIG.

In the present invention, depending on the type of magnetic tape used,
The bias variable range mentioned above has been changed to reduce the time it takes to set the recording bias value.

As described above, according to the present invention, in a VC that can automatically set the amount of recording bias applied to a magnetic tape, the resolution is changed depending on the type of magnetic tape, and the overall bias variable range is reduced to the necessary minimum. An automatic recording setting method in a magnetic recording/playback device that can reduce the time required to set the optimal recording bias value according to the type of magnetic tape. can be provided.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are diagrams for explaining a recording bias setting method in the present invention.

Claims (1)

[Claims] In a device that can automatically set the amount of recording bias applied to the magnetic tape, the resolution is changed depending on the type of magnetic tape, and the overall bias variable range is kept to the necessary minimum to achieve optimal results in a short time. An automatic recording setting method in a magnetic recording/reproducing device, characterized in that a recording bias value is set according to the recording bias value.