JPH0544881Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a circuit for controlling the recording timing of video signals and audio signals in a magnetic recording/reproducing device using a deep recording method.

(Prior Art) In a magnetic recording and reproducing apparatus (so-called high-fidelity VTR) using a conventional deep recording method, recording of video signals and audio signals is performed as follows.

As shown in FIG. 2, a pair of video heads 2, 3 and audio heads 4, 5 attached to the rotating drum 1 record and reproduce video signals and audio signals, respectively. As shown in FIG. 3, the audio heads 4 and 5 record audio signals deep into the magnetic layer 7 of the magnetic tape 6, while the video heads 2 and
3 records a video signal on the surface layer portion of the magnetic layer 7.
A hatched portion 7a indicates a portion where an audio signal is recorded, and a stippled portion 7b indicates a portion where a video signal is recorded.

(Problems to be solved by the invention) In a conventional deep recording type magnetic recording/reproducing device, the same recording control signal is used for two signals to be deep recorded, that is, an audio signal and a video signal. . Therefore, the recording pattern on the magnetic tape 6 is shifted by an amount corresponding to the shift in the mounting positions of the audio heads 4, 5 and the video heads 2, 3 attached to the rotating drum 1.

FIG. 4 schematically shows the recording pattern on the magnetic tape 6. As shown in FIG. Records are made on one track for each helical scan. At the start of recording, a track 8a is created where only the video signal is recorded, and at the end of recording, a track 8b is created where only the audio signal is recorded. The track 8b corresponds to the left end of the portion 7a where the audio signal is recorded on the magnetic tape 6 when recording is completed in the state shown in FIG. recorded.

The sound reproduced from the signal recorded in this manner has an abnormal sound near the end of recording, which is very harsh to the ears. This is because there is a sudden change in the audio level of 10 to 20 dB at the boundary where the video signal and audio signal are both recorded and the audio signal is recorded. This is because this sudden change cannot be removed by a capacitor cut that removes the DC component from the output signal of the audio head.

Therefore, the recorded signal in the part where only the audio signal is recorded has level fluctuations that exceed the AM rejiexion capability of a general FM demodulator.
This produces abnormal noise at a level that is clearly a problem for high-fidelity VTRs that have a dynamic range performance of 90 dB.

An object of the present invention is to prevent the above-mentioned abnormal noise from occurring in a magnetic recording/reproducing device using a deep recording method.

(Means for Solving the Problems) A magnetic recording and reproducing device equipped with a deep recording method according to the present invention includes a video recording control means for controlling the start and stop of recording of video signals, and a video recording control means for controlling the start and stop of recording of audio signals. It is equipped with an audio recording control means for controlling the stop, and a timing control means for controlling the start and stop timing of the video recording control means and the audio recording control means. Another feature is that the timing is controlled so that only the audio signal is not deeply recorded.

(Function) According to the present invention, the start and end timings of recording can be shifted from each other for the video signal and the audio signal. Therefore, it is possible to prevent the level of the recorded audio signal from changing suddenly.

(Embodiment) Hereinafter, an embodiment of the present invention will be described using a block diagram of a recording control circuit of a magnetic recording/reproducing apparatus shown in FIG. This recording control circuit controls the timing of recording video signals and audio signals.

The video signal recording and reproducing switching circuit 11 switches and connects the pair of video heads 2 and 3 to either the video signal recording processing circuit 12 or the video signal reproducing processing circuit 13. The video signal recording processing circuit 12 is a circuit for recording video signals on a magnetic tape using a pair of video heads 2 and 3, and the video signal recording and reproducing processing circuit 13 is a circuit for recording video signals on a magnetic tape using a pair of video heads 2 and 3.
This is a circuit for reproducing video signals recorded on magnetic tape. The video signal recording/reproduction switching circuit 11 is switched by a switching signal from a recording control processing circuit 31, which will be described later.

The audio signal recording/reproducing switching circuit 21 connects the pair of audio heads 4 and 5 to the audio signal recording processing circuit 22.
and the audio signal reproduction processing circuit 23. The audio signal recording processing circuit 22 is a circuit for recording audio signals on a magnetic tape using a pair of audio heads 4 and 5, and the audio signal recording and reproducing processing circuit 23 is a circuit for recording audio signals on a magnetic tape using a pair of audio heads 4 and 5. This is a circuit for reproducing the recorded audio signal. The audio signal recording/reproduction switching circuit 21 is switched by a switching signal from a recording control processing circuit 31, which will be described later.

The recording control processing circuit 31 is provided to the video signal recording/reproducing switching circuit 11 and the audio signal recording/reproducing switching circuit 21 either directly by switching the switching circuit 32 or indirectly through the delay circuit 33 or 34. . When this switching circuit 32 is switched to directly give a switching signal to one of the two switching circuits 11 and 21, it is configured to give the switching signal to the other one via a delay circuit 33 or 34. configured to switch. Also,
The selection circuit 35 notifies the recording control processing circuit 31 whether or not the deep recording method has been selected. The circuit described above allows the start and end of recording to be delayed by a predetermined period of time.

When the deep recording method is selected, recording is done as follows. At the start of recording, a switching signal from the recording control processing circuit 31 is transmitted directly to the video signal recording/reproducing switching circuit 11, but is transmitted to the audio signal recording/reproducing switching circuit 21 via the delay circuit 34. Therefore, recording of the video signal is first started, and then recording of the audio signal is started. On the other hand, at the end of recording, the switching signal from the recording control processing circuit 31 is transmitted to the video signal recording/reproducing switching circuit 11 via the delay circuit 33, but is directly transmitted to the audio signal recording/reproducing switching circuit 21. Therefore, recording of the audio signal is first stopped, and then recording of the video signal is stopped.

Furthermore, when the deep recording method is not used, the conventional recording method is selected.

(Effects of the invention) According to the invention, a situation in which only audio signals are deeply recorded on a magnetic tape does not occur, and therefore, generation of abnormal sounds during playback can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a magnetic recording/reproducing apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the position of a video head and an audio head mounted on a rotating drum. Figure 3 shows
FIG. 2 is a schematic cross-sectional view showing a recording situation using a video head and an audio head. FIG. 4 is a schematic plan view showing tracks on a magnetic tape. 1... Rotating drum, 2, 3... Video head,
4, 5... Audio head, 6... Magnetic tape, 7... Magnetic layer, 7a... Part where audio signals are recorded, 7b... Part where video signals are recorded, 8a... Only video signals 8b...A track on which only audio signals are recorded.

Claims (1)

[Claims for Utility Model Registration] In a magnetic recording and reproducing device equipped with a deep recording method, a video recording control means for controlling the start and stop of recording of a video signal, and an audio recording device for controlling the start and stop of recording of an audio signal. The timing control means controls the start and stop timing of the video recording control means and the audio recording control means, and the timing control means allows only the audio signal to be recorded when recording by the deep recording method. A magnetic recording/reproducing device characterized by controlling timing to prevent deep recording.