JPH0562344A - Audio magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To obtain an easy-to-listen sound by correcting the changes of both volume increase and quality balance of a reproduced sound when a tape recorder and a VTR are run at a high speed. CONSTITUTION:The resistor 5 is connected to the integrating condensor 3 of the feed back circuit of a reproducing equalizer circuit in series, this device is provided with a controlling means so as to make the value of the resistor 5 small at the time of high-speed travelling and at the time of n time speed, a controlling is executed so as to make the high area defecting frequency of a reproducing equalizer frequency characteristic n times than at the time of a normal speed and thus, the easy-to-listen sound is obtained by eliminating the changes of the average sound volume and quality balance at the time of a high speed running.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio tape recorder or an audio magnetic recording using an audio reproduction equalizer circuit of a video tape recorder (hereinafter abbreviated as VTR) having an audio recording track for recording in a longitudinal direction of a magnetic tape. Reproduction device

[0002]

2. Description of the Related Art In recent years, audio tape recorders have been remarkably popularized and various proposals have been made for their uses. In particular, when searching where on the tape surface the recording is performed, it is often requested that the tape be run at a high speed and that a reproduced sound is generated with an appropriate volume and sound quality.

A conventional audio magnetic recording / reproducing apparatus will be described below with reference to the drawings.

As shown in FIG. 3, in the reproducing equalizer circuit used in the conventional audio magnetic recording / reproducing apparatus, the output signal from the magnetic head 1 is amplified by the amplifier 2 and output from the output terminal 7, but the capacitor 3, A feedback circuit composed of the resistor 4, the first resistor 5 and the second resistor 6 is provided between the output side of the amplifier 2 and the negative phase input side.

The operation of the reproducing equalizer circuit of the audio magnetic recording / reproducing apparatus configured as described above will be described below.

First, an audio tape recorder and a VT
The reproducing circuit of the R audio track in the longitudinal direction of the tape is basically an integrating circuit. This is because the reproduction output characteristic of the magnetic head has a differential characteristic proportional to the frequency. However, high frequency loss factors such as gap loss and spacing loss exist between the magnetic tape and the magnetic head. In order to correct this, in the reproduction equalizer circuit, as shown by the solid line in FIG. 2, the part above a certain bending frequency f ₂ has a flat characteristic instead of an integral characteristic.

Next, in FIG. 3, assuming that the value of the capacitor 3 is C ₃ , and the values of the resistors ₄ , ₅ and ₆ are R ₄ , R ₅ and R ₆ , respectively, the frequency f _{1 of} FIG. And f ₂ is (Equation 2)
Can be expressed as

[0008]

[Equation 1]

[0009]

[Equation 2]

Since R ₄ is usually sufficiently larger than R ₅ and R ₆ , f ₂ can be approximated by (Equation 3).

[0011]

[Equation 3]

Here, when a tape recorder or VTR is used for a search operation, the magnetic tape is run at high speed while listening to the reproduced sound. At this time, when traveling at a speed n times the steady speed, the frequency of the signal reproduced by the magnetic head becomes n times, and since the magnetic head has differential characteristics, the magnetic head reproduction output level of each frequency component is increased. Becomes n times (especially because gap loss and spacing loss do not change). Therefore, if the reproduction equalizer characteristic is the integral characteristic, the level of each frequency component of the reproduction equalizer output does not change, that is, the balance of the sound quality does not change, and the frequency simply becomes n times. In the reproduction equalizer circuit with such characteristics,
Since f _{2 and} above are not integral characteristics but are flat, frequency components above f ₂ are increased n times to enhance the high frequency range, that is, the sound quality is out of balance, and the average volume is also increased. It becomes a sound. This state is shown in Figure 4.
Shown in. FIG. 4A shows the frequency characteristics of the reproduced sound when reproduced at a constant speed, and the shaded area shows the energy distribution of the reproduced sound. FIG. 4B shows the frequency characteristics and the energy distribution of the reproduced sound when reproduced at n times speed, and the energy distribution is biased toward the higher frequency as the speed is increased by n times.

In order to eliminate such annoying sound when running at high speed, a method of inserting an attenuator as shown in FIG. 5 on the output side of the reproduction equalizer has been conventionally used. 5, the same components as those in FIG. 3 are designated by the same reference numerals and correspond to each other. The resistors 8 and 9 constitute an attenuator, and a switch 10 is provided, and the switch 10 is closed during high-speed traveling so that the reproduction equalizer output is attenuated. However, although such a method has an effect of suppressing an increase in volume during high-speed traveling reproduction, it has no effect of correcting the balance of sound quality.

[0014]

However, in the above-mentioned conventional configuration, when performing a search operation with a tape recorder or a VTR, when the magnetic tape is run at a high speed while reproducing a sound, a constant speed is not obtained. When driven at a speed of n times, the frequency of the signal reproduced by the magnetic head becomes n times, and the magnetic head reproduction output level of each frequency component also becomes n times. There was a problem that it was done.

The present invention solves the above-mentioned problems of the prior art. Audio magnetic recording for reproducing an easily audible sound by correcting both an increase in the volume of the reproduced sound of a tape recorder or a VTR at high speed and a deterioration in the sound quality balance. An object is to provide a reproducing device.

[0016]

In order to achieve the above object, the audio magnetic recording / reproducing apparatus of the present invention is such that the value of the resistance connected in series to the integrating capacitor of the feedback circuit of the reproducing equalizer circuit is high-speed running. The control means is provided so as to decrease the frequency, and at the n-fold speed, the high-side bending point frequency of the reproduction equalizer frequency characteristic is controlled to be n times that at the steady speed.

[0017]

With the above-described structure, the present invention can prevent the response level of the frequency of f ₂ or more from increasing by n times during high-speed running, and can make the sound easy to hear without changing the average volume and the sound quality balance. ..

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same components as those shown in FIG. 2 of the above-mentioned conventional example are designated by the same reference numerals, and the description thereof will be omitted. The characteristic configuration of this embodiment is that a switch 11 and a third resistor 12 are newly added.

The operation of the main circuit of the audio magnetic recording / reproducing apparatus having the above structure will be described with reference to FIG.

When the magnetic tape is running at a constant speed, the switch 11 is open, and the frequency characteristic of the reproduction equalizer circuit forming the main circuit of this embodiment is f as shown by the solid line in FIG. _A characteristic of bending at ₂ .

Next, when the magnetic tape running speed becomes n times, the switch 11 is closed, and as a result, the bending frequency on the high frequency side of the frequency characteristic of the equalizer circuit rises to f ₃ .
This state is shown by the broken line in FIG. Where the value of resistor 12 is R
_When f is ₁₂ , f ₃ is represented by (Equation 4).

[0023]

[Equation 4]

Since R ₄ is usually sufficiently larger than R ₅ and R ₆ , f ₃ can be approximated by (Equation 5).

[0025]

[Equation 5]

If f ₃ is set to be n times as large as f ₂ , the average volume of reproduced sound and the sound quality balance do not change even if the magnetic tape running speed becomes n times. The reason will be described below.

First, when the magnetic tape is running at a constant speed, the reproduction level of the magnetic head becomes n times as high as the n-fold speed of components below f ₂ , but the characteristic of the reproducing equalizer circuit is f ₃ or nf _2. Since the integration characteristic is extended up to, the output of the reproduction equalizer circuit does not change. In addition, the component of f ₂ or more at the steady speed was originally equalized in the flat portion, but at the n-fold speed, the reproduction level of the magnetic head becomes n times, but the portion of the reproduction equalizer circuit at f ₃ or more is equal to or greater than n. That is, since the response is equalized at a flat portion of 1 / n with respect to the steady speed, the output of the reproduction equalizer does not change.

Therefore, the value of R ₁₂ satisfying f ₃ = nf ₂ is obtained from the following (Equation 6) using (Equation 3) and (Equation 5).

[0029]

[Equation 6]

Although only one set of the circuit in which the switch 11 and the third resistor 12 are connected in series is provided in the present embodiment, a plurality of circuits are provided when the speed during high-speed running changes in multiple stages. A pair of switches and resistors may be provided and the switches may be switched according to the speed.

The value of the resistor 12 is 0, that is, the resistor 12
The same applies to those without.

[0032]

As described above, according to the present invention, means for controlling the value of the resistor connected in series to the integrating capacitor of the feedback circuit of the reproduction equalizer circuit to be small during high speed traveling is provided, and n-fold speed is provided. At times, the bending point frequency on the high frequency side of the reproduction equalizer frequency characteristic is controlled to be n times that at steady speed, so that the average volume and sound quality balance during high-speed running do not change and the sound becomes easy to listen to. It is possible to realize an excellent audio magnetic recording / reproducing apparatus capable of performing the above.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a main part of an audio magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 Frequency characteristic diagram of the same circuit

FIG. 3 is a circuit diagram of a main part of a conventional audio magnetic recording / reproducing apparatus.

FIG. 4 (a) is a frequency characteristic diagram of a tape in the same circuit at a constant speed, and (b) is a frequency characteristic diagram of a tape in the same circuit at an n-fold speed.

FIG. 5 is another circuit diagram of a main part of a conventional audio magnetic recording / reproducing apparatus.

[Explanation of symbols]

 1 Magnetic Head 2 Amplifier 3 Capacitor 5 First Resistor 6 Second Resistor 11 Switch 12 Third Resistor

Claims (3)

[Claims] 1. A magnetic head for reproducing an audio signal recorded in a longitudinal direction of a magnetic tape, an amplifier whose output from the magnetic head is input to a positive-phase input terminal, and a negative phase of the output of the amplifier. A series connection circuit of a capacitor and a first resistor connected between the input terminals, a second resistor connected between the negative phase input terminal of the amplifier and the ground, and the running speed of the magnetic tape increases. An audio magnetic recording / reproducing apparatus comprising: a control means for controlling the value of the first resistance to be small. 2. The audio magnetic recording / reproducing apparatus according to claim 1, wherein the control means comprises a switch connected in parallel to the first resistor or a series connection circuit of a switch and a third resistor. 3. A switch or a plurality of series-connected circuits of a switch and a third resistor are provided, and predetermined ones of the switches are sequentially switched according to a tape speed. Audio magnetic recording and reproducing device.