JPS60109044A - Intermusic space detection system - Google Patents

Abstract

PURPOSE:To detect an intermusic space easily and accurately by recording a signal except at an intermusic space and detecting absence parts of a synchronizing signal during reproduction. CONSTITUTION:An audio signal is digitized by an A/D converter 1, PCM-modulated by a PCM circuit 2, mixed with the synchronizing signal of a synchronizing signal generator 2 by a mixer 4 to obtain a video format signal. This signal is supplied as a recording signal to VTR7 through a muting circuit 5, but the circuit 5 inhibits the supply while a mute switch 6 is on. The playback signal of the VTR7, on the other hand, is applied to a synchronous separator 9 to extract only the synchronizing signal B selectively, and this signal B is inputted to a synchronizing signal absence detector 10 to detect absence parts of the synchronizing signal. The output C of the detector 10 is inputted to an intermusic space display 12 through a driver circuit 11 to detect an intermusic space easily and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting between songs, and more particularly to a method for detecting between songs in a PCM (Pulse Code Modulation) processor for A-to-A information.

In the PGM processor for consumer use, audio signals such as music are digitized using the PCM method, and a synchronization signal of the video signal (3) composite signal is added to this digital signal to convert it into a so-called deoff A-mat signal, and this converted signal is is supplied to a VTR (video tape recorder) and recorded on videotape.

During playback, this videotape is played back again using V T'R, and the PCM signal is converted to video format 1.
- Separate and extract from the signal and demodulate it to obtain a reproduced audio signal.

In such a system, in order to know the time between songs, there are two methods: use a VTR counter or rely on reproduced sound. The former method is to read and record the value of a counter between songs during recording, and to know the time between songs based on the counter value during playback. The latter method involves fast forwarding,
This is a method of knowing the time between songs while listening to the reproduced sound by key operations such as rewinding or video search.

The method using a counter has the disadvantage that it lacks effectiveness because the counter value between songs needs to be known. Furthermore, the method using reproduced sound has the disadvantage that the reproduced sound during fast-forwarding is very audible, and it is necessary to tune out this unpleasant noise while searching between songs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for detecting gaps between songs easily and accurately.

The song interval detection method according to the present invention detects portions of A-dio information corresponding to the inter-song portions when recording audio information digitized into a video format 1 signal into a predetermined medium. The present invention is characterized in that the recording is performed with at least a synchronizing signal missing, and when playing back, the missing portion of the playback synchronizing signal can be detected to detect the gap between songs.

The present invention will be explained below using the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention during recording. The audio A signal of music etc. to be recorded is A/D.
'(analog/digital) converter 1 resamples the signal and digitizes it.

Thereafter, it is converted into P and CM in the PGM circuit 2, and combined with the synchronization signal from the synchronization signal generator 2 in the synthesizer 4 to form the video format 1 signal.

The video format 1 signal is supplied to the VTR 7 as a recording signal via the mute circuit 5.

This mute episode +! 85, while the mute switch 6 is turned on, the video format signal is output to the VTR 7.
Prohibits the supply of such signals to

FIG. 2 is a diagram showing an example of the mute circuit 5 in FIG. 1,
1~ transistor for switching between video format signal line 8 and ground. 1 is inserted, and this transistor Q1 is controlled on and off by a mute switch 6.

When the mute switch 6 is turned on, a bias voltage that is By turning on transistor 6, transistor 1 is turned on, dropping the signal line 8 to ground potential, and the video format signal is cut off.Therefore, if there is a gap between songs during recording, the mute switch is turned on. If the switch 6 is turned on, the signal to the video format 1 will not be supplied to the VTR, so that not only PCM signals but also synchronization signals and the like will not be recorded on the video tape.

FIG. 3 is a block diagram at the time of reproduction of an embodiment of the present invention,
The reproduced signal (Δ) from the VTR 7 (see FIG. 1) is applied to the sync separator 9, and only the sync signal is selectively extracted. This synchronization signal (B) is input to a synchronization signal loss detector 10 to detect the missing portion of the synchronization signal. This detection output (C) is passed through the driver circuit 11 and becomes an input signal to the song interval indicator 12.

FIG. 4 shows a circuit example of the synchronization signal loss detector 10 in FIG. The collector output of this L-transistor Q2 is applied to a time constant circuit made up of a resistor R5 and a capacitor C1. The output of this time constant circuit is compared in level with a reference level by a voltage dividing circuit of resistors Re and R7 in the level comparator of the first amplifier Δ1. This comparison output becomes the synchronization signal loss detection signal (C).

Here, there is no level comparison output while the synchronization signal is being supplied, but if the synchronization signal is missing for a period longer than the time determined by the time constant of resistor R5 and capacitor C+ and the reference level, the level comparison signal (C) is output. Change from low level to high level.

FIG. 5 is a waveform diagram showing the operation of the blocks in FIG. 3;
Figures (A) to (C) respectively show the waveforms of the signals (A) to (C) in Figure 3, respectively. If the video format signal recorded on the video tape is missing due to muting during the period corresponding to the interval between songs as shown in Figure (A), the synchronization signal of the playback signal will also be missing during that period as shown in Figure (B). .

Therefore, the detection signal of the synchronization signal loss detector 10 is as shown in Figure (C).
The inter-song indicator 12 is turned on at the portion corresponding to the inter-song interval, so that it is possible to detect the inter-song interval.

As described above, according to the present invention, when a PCM signal is superimposed on a video format signal and recorded, all the signals in the inter-track portions are deleted and recorded, and upon playback, the synchronization signal is deleted. Since the intervals between songs are detected by detecting the parts, it is possible to easily and accurately detect the intervals between songs. In addition, when searching for a gap between songs using fast-forwarding, rewinding, or fast-forwarding, you can easily detect the gap between songs, so you can turn down the volume and prevent the generation of noise. .

Incidentally, although the mute circuit 5 is provided after the synthesizer 4 in the above-mentioned case-C, it is also possible to provide a mute circuit for only the synchronization signal inside the synthesizer 4. Also, analog audio r ′
It may be configured such that when the A-times signal level falls below a certain level, it is assumed that there is an interval between songs, and the video A-mat signal or synchronization signal is muted during that time.

The synchronization signal loss detector 10 is not limited to the configuration shown in FIG. 174 may be constructed as shown in FIG.
J
3. If the time constant of this MMV is made slightly longer than the period of the synchronization signal, if the playback synchronization signal is lost, the MMV will revert to 1~
Since it is no longer triggered, detection of signal loss becomes 17J.

Furthermore, instead of using a display device, it is also possible to use an audible device such as a buzzer.7j, PCM (g.
A VTR was used to record and play back the numbers, but a VDR (video disc player) is also useful.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention during recording, and FIG. 2 is a diagram illustrating an example of the circuits from MU1 in FIG. 1. FIG. 3 is a block diagram of an embodiment of the present invention during reproduction, FIG. 4 is a diagram showing an example of the synchronization signal loss detector shown in FIG. 3, and FIG. 5 is a diagram showing operating waveforms of the device shown in FIG. 3. It is a diagram. Explanation of symbols of main parts 2... PCM circuit 3... Synchronization signal generation circuit 4... Synthesis circuit 5... Mute circuit 7...・VTR 9...Sync separator 10...Sync signal loss detector 12...Display device Applicant Pioneer Co., Ltd. agent Attorney Motohiko Fujitoshi (1 other person) )

Claims (1)

[Claims] When superimposing the digitized A-D information on the video format 1 signal and recording it on a predetermined recording medium,
A song characterized in that the audio information is recorded with at least a synchronization signal missing in a portion corresponding to between songs, and upon playback, the gap between songs can be detected by detecting the missing portion of the playback synchronization signal. Interval detection method.