JPH08306128A - Recording and reproducing device - Google Patents

Abstract

PURPOSE: To faithfully reproduce the level changes of original signals by simultaneously recording the gain information of a recording on a different channel than the input signals while conducting an AGC operation and executing a reverse control during a reproducing. CONSTITUTION: During a recording, the inputted signals from a preamplifier 1 are recorded on a magnetic tape 21 through a digital signal processor(DSP) 5. During a reproducing, the recorded data are read by a magnetic head 7 and outputted to a speaker through the DSP 5. Simultaneously, the AGC information, which performs the gain control during a recording, is controlled by a first attenuator 2 based on the instruction of a controller 11 by comparing the signal level read by the DSP 5 and a reference level. During a reproducing, the controller 11 conducts an AGC operation by controlling the DSP 5 and a second attenuator 9 using the read AGC information. Thus, the signal levels during a recording are faithfully reproduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio signal recording / reproducing apparatus such as a tape recorder or a video tape recorder. More specifically, the present invention relates to a recording / reproducing apparatus such as a tape recorder which records an analog audio signal as a digital signal.

[0002]

2. Description of the Related Art Conventionally, in a recording / reproducing apparatus such as a tape recorder, AGC (automatic gain control) is used at the time of recording.
The signal level is controlled by the function. In this case, if the AGC is controlled so as to be sufficiently effective, the low sound and the high sound will be at the same level.

As a result, for example, in classical music, the music lacks excitement and lacks excitement. On the contrary, when the effect of AGC is set weak, there are problems such as distortion at a high volume and deterioration of the S / N ratio at a low volume.

[0004]

According to the present invention, the optimum AGC control cannot be performed in the conventional recording / reproducing apparatus.
It is an object of the present invention to provide a recording / reproducing apparatus capable of solving the above-mentioned inconvenience and faithfully reproducing the level change of the original signal.

[0005]

According to the present invention, firstly,
In a recording device that has an AGC function that automatically controls the gain according to the level of an input signal, and that converts an analog signal such as a voice signal into a digital signal and records it,
The gain control information and the input signal are simultaneously recorded on another channel.

Secondly, the first recording / reproducing apparatus is provided with means for detecting the time when the gain actually changes and recording the time information, and recording the time information together with the gain control information. ing.

Thirdly, in the first recording / reproducing apparatus, the gain control information is read at the time of reproduction, and the gain control opposite to the read gain control information is performed for reproduction.

[0008]

Embodiments of the recording / reproducing apparatus of the present invention will now be described in detail with reference to the drawings. According to the present invention, in an apparatus for recording a voice signal or the like, an AG
When performing the C operation, the gain information at the time of recording is also recorded at the same time, and the reverse gain control is performed at the time of reproduction, so that the level change of the original signal can be faithfully reproduced. are doing.

FIG. 1 is a functional block diagram showing an embodiment of the main configuration of the recording / reproducing apparatus of the present invention. In the figure, 1 is a preamplifier, 2 is a first attenuator, 3 is a recording amplifier, 4 is an A / D converter, 5 is a digital signal processor (DSP), 6 is a magnetic recording / reproducing amplifier, and 7 is magnetic. A head, 8 is a D / A converter, 9 is a second attenuator, 10 is a reproducing amplifier, 11 is a controller, and 12 is a magnetic tape.

In the recording apparatus shown in FIG. 1, at the time of recording, a signal from a microphone or the like (not shown) is preamplifier 1 → first attenuator 2 → recording amplifier 3 → A
The data is recorded on the magnetic tape 12 through the / D converter 4, the digital signal processor 5, the magnetic recording / reproducing amplifier 6, and the magnetic head 7.

The preamplifier 1 shown in FIG. 1 is an amplifier for performing input impedance conversion, level conversion, and the like. The first attenuator 2 is an attenuator for attenuating the signal level of the input signal. The controller 11 has a function of controlling the entire recording / playback system shown in FIG.

The digital signal processor 5 is an A / D
An error correction code is added to the digital signal output from the converter 4 or modulation for recording is performed. Further, incidental information called CTL is also added by the digital signal processor 5. Note that ATT (attenuation amount) information and change time (change time) information are also included as one of the additional information. Further, in the AGC operation, the controller 11 reads the signal level by the digital signal processor 5 and compares it with the reference level.

When the level of the read signal is higher than the reference level, the first attenuator 2 is controlled to reduce the gain of the signal. If it is lower than the reference level, the gain is increased. The controller 11 also controls the attenuation amount of the first attenuator 2 through the digital signal processor 5. Next, when recording,
The AGC operation performed by the controller 11 will be described in detail.

As mentioned above, the controller 11 is
The digital signal processor 5 reads the signal level. If the gain is changed when the amplitude of the signal is large, a so-called small sound is heard. Therefore, the attenuation value of the first attenuator 2 is changed through the digital signal processor 5 at the moment when the signal level becomes close to zero. The attenuation value in this case is determined by the controller 11.

The information regarding the attenuation value thus determined, that is, the information about when and which value the attenuation value of the first attenuator 2 is set to is held in the digital signal processor 5. . Therefore, information on the attenuation value indicating when and which value is set is recorded in the CTL as AGC information.

For example, in the case of an NT recorder, information recording is performed by a rotating drum every 20 msec.
Since the sampling frequency is 32 KHz, 640 samples per trace (in stereo, the number of data is doubled) is recorded. On the other hand, AGC control is 5m
Since the period is about sec, recording may be performed at most 4 times within 20 msec.

The data amount of AGC information to be recorded is ATT.
A value of 8 bits (1.25 dB steps) and time information of 10 bits are sufficient. The AGC information recorded during recording in this way, that is, the ATT (attenuation amount) information and the change time (change time) information are used during reproduction. The flow chart of the AGC operation during the above recording is shown.

FIG. 2 is a flow chart showing the main processing flow of the recording operation of AGC information during recording in the recording / reproducing apparatus of the present invention.

The controller 11 reads the signal level of the recording signal in the digital signal processor 5.
Then, this signal level is compared with the reference level to check the magnitude of both. If they are equal, the attenuation value of the first attenuator 2 is not changed.

If the signal level is higher than the reference level (signal level> reference level), the attenuation value is increased so that both levels become equal. Then, the attenuation value and information about the time (ATT information and change time information) are recorded. If the signal level is lower than the reference level (signal level <reference level), the attenuation value is reduced so that both levels become equal.

Also in this case, the attenuation value and the time information are recorded. As described above, A during recording
The recording operation of the GC information is performed, and the ATT information and the change time information are recorded on a predetermined track on the magnetic tape 12. At the time of reproduction, this AGC information is read in a channel together with a digital signal such as an audio signal and used for the AGC operation of the reproduction signal. Next, the operation during reproduction will be described.

At the time of reproduction, the digital data read from the magnetic tape 12 by the magnetic head 7 is converted into a magnetic recording / reproducing amplifier 6 → digital signal processor 5.
-> D / A converter 8-> 2nd attenuator 9-> It passes through the amplifier 10 for a reproduction | regeneration, and is output to a speaker, earphones, etc. which are not shown in figure. In this case, the AGC information recorded during recording is read at the same time as the digital signal such as the audio signal.

Then, the attenuation amount of the second attenuator 9 is controlled by using the AGC information read out at the same time. The controller 11 also controls the attenuation amount of the second attenuator 9 through the digital signal processor 5. In this case, the signal can be reproduced at the level before the AGC operation by controlling the attenuation amount (actually, controlling the ATT value by the opposite amount) according to the time information.

Therefore, according to the recording / reproducing apparatus of the present invention, the dynamic range of recording / reproducing is larger than the limitation by the A / D converter 4, the D / A converter 8 or the recording format by the amount controlled by the AGC. it can. In this way, since the level change of the original signal can be faithfully reproduced, it is not necessary to switch the AGC performance according to the type of sound source. Even if a magnetic tape recorded by using the recording / reproducing apparatus of the present invention is set in the conventional recording / reproducing apparatus and reproduced, there is no problem in the reproducing operation itself.

[0025]

According to the recording and reproducing apparatus of the first aspect, the gain control information is simultaneously recorded on the channel different from the input signal. Therefore, the gain control information can be read and used during reproduction.

In the recording / reproducing apparatus according to the second aspect, the gain control information according to the first aspect is recorded together with the information on the time when the gain is changed. Therefore, at the time of reproduction, the information on the time when the gain changes can be used together with the gain control information.

In the recording / reproducing apparatus of claim 3, during reproduction,
The gain control information of claim 1 is read, and the gain control opposite to the read gain control information is performed for reproduction. Therefore, the dynamic range of recording and reproduction is more limited than the A / D converter 4, the D / A converter 8, or the recording format.
It is possible to increase the amount of control by C, and it is possible to faithfully reproduce the level change of the original signal.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of the main configuration of a recording / reproducing apparatus of the present invention.

FIG. 2 is a flowchart showing a main processing flow of recording operation of AGC information during recording in the recording / reproducing apparatus of the present invention.

[Explanation of symbols]

 1 Preamplifier 2 First Attenuator 3 Recording Amplifier 4 A / D Converter 5 Digital Signal Processor (DSP) 6 Magnetic Recording / Reproducing Amplifier 7 Magnetic Head 8 D / A Converter 9 Second Attenuator 10 Reproducing Amplifier 11 controller 12 magnetic tape

Claims (3)

[Claims] 1. A recording device having an AGC function for automatically controlling a gain according to a level of an input signal and converting an analog signal such as a voice signal into a digital signal for recording, wherein gain control information is separated from the input signal. A recording / playback device characterized by simultaneously recording on channels. 2. The recording / reproducing apparatus according to claim 1, further comprising means for detecting a time when the gain actually changes and recording time information, wherein the time information is recorded together with the gain control information. Recording and playback device. 3. The recording / reproducing apparatus according to claim 1, wherein the gain control information is read at the time of reproduction and the gain control opposite to the read gain control information is performed for reproduction. apparatus.