JPH02278565A - Sound muting device for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To cancel a unnatural tone to be generated when a tape speed is switched by muting the sound at the time of both recording and reproducing when the tape speed is switched. CONSTITUTION:When a magnetic recording and reproducing device is in a recording state and the speed is switched from a standard mode to a three-times mode, an 'H' level signal is simultaneously generated for a fixed time in the output of a tape speed switching time mute control signal generating circuit 7. Only during the time of the 'H' level, a sound mute circuit 4 is operated and the input signal of a recording amplifier 2 is muted by the circuit 4. Even at the time of the reproducing, the circuit 4 is samely operated as the time of the recording and the output of a reproducing amplifier 2 is muted by the circuit 4. Thus, both the unnatural tone, which is generated by servo deviation when the speed at the time of the recording is switched, and the unnatural tone, which is caused by a switching signal when the speed is switched at the time of the reproducing, can be removed.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention is applicable to magnetic recording and reproducing devices that are standard → 3 times
This invention relates to a device that mutes audio when switching tape speed modes, such as from double to standard.

[Prior Art] FIG. 5 shows a conventional audio mute device of this type, in which 1 is an audio output amplifier, 2 is a playback amplifier, 3 is a recording amplifier, 4 is an audio mute circuit, and 5. 6 is a circuit that generates an audio mute control signal when switching the tape speed; circuit 5 generates an audio mute control signal only during playback, and circuit 6'' generates an audio mute control signal only during recording.

Next, the operation will be explained based on FIG. Conventional devices employ only one of a circuit 100 that mutes the recording amplifier input during recording and does not mute during playback, or a circuit 200 that mutes the playback amplifier output during playback but does not mute during recording.

The operation of circuit 100 is as follows. That is, the audio mute circuit 4 is a circuit that mutes the audio when it receives an "H" level control signal at its control terminal, and when the tape speed is changed, the audio is muted.
By receiving the I level signal, the three recording amplifiers are muted to prevent audio from being recorded on the magnetic tape.

The circuit 200 also outputs a mute control signal generating circuit 5 to the audio mute circuit 4 at the time of tape speed switching.
By outputting the level signal, the output of the reproduction amplifier 2 is muted, and the reproduction signal is not sent to the audio output amplifier 1.

[Problem to be solved by the invention]

Conventional audio muting devices are configured as described above, so if you mute only during recording, an abnormal sound will be emitted during playback due to the TV speed mode switching signal (Figure 6). If only the tape is muted, the servo is disconnected when switching the tape speed and the tape speed is disturbed, so the mute start time is delayed by the tape speed mode determination time, and the audio during the tape speed mode determination time is output as an abnormal sound. There was a problem (Figure 7).

This invention was made in order to solve the above-mentioned problems with the conventional ones, and its purpose is to provide an audio mute device for a magnetic recording and reproducing device that can eliminate the abnormal noise that occurs when switching tape speeds. do.

[Means to solve the problem]

The audio mute device for a magnetic recording/reproducing apparatus according to the present invention mutes the audio when switching the tape speed during recording, and also mutes the audio when switching the tape speed during playback.

[Effect]

In the audio mute device of the present invention, by muting the audio during recording, the abnormal noise generated during the tape speed mode discrimination time during playback is eliminated, and by muting the audio during playback, the abnormal noise generated during playback is eliminated. do.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an audio mute device for a magnetic recording/reproducing apparatus according to an embodiment of the present invention, and in the figure, the same reference numerals as in FIG. 5 indicate the same or corresponding parts, respectively. 7 is a control signal generation circuit for mu 1 when switching tape speed;
When the transistor 5 is turned on, it controls the audio mute circuit 4 to mute the reproduced or recorded sound.

Reference numeral 16 denotes a recording/reproduction discrimination control circuit which turns on the transistor 5 during recording and reproduction.

Next, the operation will be explained. When the magnetic recording/reproducing apparatus is in the recording state and the tape speed is not switched from the standard mode to the triple mode, the output of the tape speed switching mute control signal generation circuit 7 is rH for a certain period of time at the same time as the tape speed is switched.

level signal is generated, and at this time the transistor 5 is turned on by the recording/reproduction discrimination control circuit 16), its r
The audio mute circuit 4 operates only during the time of level H.
Mute the human input audio signal of the recording amplifier (see Figure 2). During reproduction, each circuit operates in the same manner as during recording, and the output of the reproduction amplifier 2 is muted by the audio mute circuit 4 (see FIG. 3). Therefore, abnormal noises that appear during playback when muted only during recording can be eliminated by muting during playback, and abnormal noises that appear due to servo disconnection when muted only during playback can be eliminated by muting during recording (see Figure 4). ).

In this way, according to this embodiment, since the audio is muted both during recording and during playback, it is possible to eliminate the occurrence of abnormal noise when switching tape speeds.

In addition, in the above explanation, only the case of switching the tape speed from standard mode to 3x mode, but
It goes without saying that the same operation as described above is performed when switching from the double mode to the standard mode.

Although the above embodiment describes the case of switching between the standard mode and the 3x mode, it can of course be applied to the case of switching to other double speed modes such as the 2x mode, and the same effects as in the above embodiment can be obtained.

Furthermore, the above embodiment is intended to be used in a magnetic recording/playback device that has a function of just recording, that is, automatically switching to 3x mode when the remaining tape capacity becomes low while recording in standard mode. Of course, the present invention can also be applied to a device in which the tape 3-pead is manually switched, and the same effects as in the above embodiment can be obtained.

Further, although the above embodiment assumes the case of recording and reproducing on a normal audio track, it can of course be applied to HiFi audio by deep recording, and the same effects as in the above embodiment can be obtained.

Further, in the above embodiment, a transistor is used as a control element, but other switching elements may be used or the audio mute circuit may be directly controlled by microcomputer software, similar to the above embodiment. The effect of this can be obtained.

[Effects of the Invention] As described above, according to the audio mute device for a magnetic recording/reproducing device according to the present invention, the audio mute is performed both during recording and during playback when switching the tape speed, so that This has the effect of eliminating abnormal noise when switching speeds.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an audio mute system for a magnetic recording/reproducing device according to an embodiment of the present invention, FIG. 2, FIG.
Figure 4 is a waveform diagram of each part during recording, playback, and self-recording/playback, Figure 5 is a diagram showing the configuration of a conventional audio mute system, and Figure 6 is a case where audio is muted only during recording. FIG. 7 is a time chart when audio is muted only during playback. In the figure, l is an audio output amplifier, 2 is a playback amplifier, and 3
4 is a recording amplifier, 4 is an audio mute circuit, 5 is a transistor, 16 is a recording/playback discrimination control circuit, and 7 is a mute signal generation circuit when switching tape speeds.

Claims (1)

[Claims] (1) A device for muting audio when switching tape speeds of a magnetic recording and reproducing device, characterized in that audio muting when switching tape speeds is performed both during recording and during playback. Mute device.