JPH0356891Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a cue signal generating device for searching a recording position on a tape in a cassette deck or the like.

[Technical background of the invention]

Currently, audio-visual equipment includes a voice slide projector that works with a tape recorder, a random access player that searches for and plays a random recording location, and a tape recorder (mainly a playback device) that uses a cue to search for a guidance recording location and detect the end of the recording. signals are used. This cue signal is recorded in the middle of the narration part of the recorded tape and the recording part of music, etc. During playback, this cue signal is detected and the designated narration part is played back, or automatic music selection (automatic cueing) is performed. ) is being played.

The cue signal necessary for this search is formed by a waveform with a constant frequency as shown in FIG. 1, but the frequency etc. differs somewhat depending on the device. In addition, the recording method is the same as the previous method, by bringing the recording head into contact with the recording tape and passing a cue signal current through the head, the magnetic tape is running at a constant speed and the cue signal current changes. Recording is achieved by leaving residual magnetism.

[Problems with background technology]

In this way, to record a cue signal, apart from the electrical system, the recording waveform on the tape depends on the inductance of the recording head coil and the recording energy component, as shown in Figure 1. It is extremely difficult to record without causing damping in certain parts, and there are many restrictions.

In such a situation, a waveform with damping occurring at the beginning and end of the cue signal is recorded, as shown in Figures 2 to 4 (including damping due to waveform disturbances that occur during high-speed damping).
The cue signal detection method has been used to cue and play back the specified narration section at a constant speed, and the cue and playback have also been performed using high-speed forward search and high-speed rewind search. Because there is waveform disturbance and damping at the end of the song, the cue signal is not detected as one signal (as a mark), but as two or three signals. Insanity will occur. Then, the next specified narration cannot be played back, resulting in a malfunction.

This type of damping is thought to be caused by the interaction of the overall electrical characteristics of the head, recording, and playback amplifiers. Of these, to briefly describe the head, as is well known, the head is a core with a coil wound around it, and this head has two properties: a self-induction effect and a change in impedance depending on frequency.

Of these, the former self-induction effect generates a back electromotive force at the beginning and end of the current flow, and is expressed as E=-Ld _i /d _t .

Therefore, it is considered that the low level of the first wave of the four-wave burst in the video system and the jump at the end of the four-wave burst are due to this self-induction effect. This back electromotive force increases as the current change increases.

On the other hand, in the case of the latter change in impedance with frequency, lower frequencies have lower impedance;
Current flows easily; conversely, high frequencies have high impedance, making it difficult for current to flow. for example
This seems to be related to the fact that no overshoot or ringing phenomenon is observed at frequencies between 1kHz and 5kHz. In other words, the current flow is low,
It is thought that the back electromotive force is also small.

In addition, as a result of the inventors' experiments, the frequency range from about 7kHz to 100kHz
A phenomenon similar to the 4-Hz burst appears, and it seems that the characteristics of the recording and playback amplifiers are related to the problem of the transient characteristics of the recording amplifier.

Note that the degree of overshoot and linking varies depending on the equipment used, and this is thought to be due to differences in the amplifier characteristics of the deck and the inductance of the head.

[Purpose of invention]

This invention has been made in consideration of the above points, and provides a cue signal generating device in which the waveforms at the beginning and end are in a zero-crossing state, no damping waveform is generated, and no address selection error occurs when selecting an address for narration. The purpose is to

[Summary of the idea]

The cue signal generator of this invention has 16 points of the cue signal fundamental wave component at the leading edge of the cue signal fundamental wave component.
The half-waves of each frequency component of twice, eight times, four times, and twice are sequentially synthesized into a continuous waveform, and the trailing edge of the cue signal fundamental wave is
A cue signal waveform is created by successively synthesizing the half-wave waveforms of frequency components of double, eight times, and sixteen times, and the cue signal of this waveform is placed in front of each narration on a track of a recording tape different from the narration. It was designed to be recorded.

[Example of idea]

Embodiments of the cue signal generating device of this invention will be described below with reference to the drawings. FIG. 5 is a queue signal waveform diagram applied to this embodiment, and 1 in FIG. 5 is the queue signal fundamental wave.
The frequency component of the leading edge of this cue signal fundamental wave 1 is 16 times 1a, 8 times 1b, 4 times the cue signal fundamental wave component.
The half-waves of the frequency components of double 1c and double 1d are synthesized into a continuous waveform and synthesized into the basic waveform 1 of the queue signal.

Also, at the trailing edge of the queue signal fundamental wave 1, the waveforms of each half wave of the frequency components of 2 times 1e, 4 times 1f, 8 times 1g, and 16 times 1h of this queue signal fundamental wave component are successively synthesized. I am trying to create a queue signal waveform.

Such a queue signal waveform is generated by a queue signal generator as shown in FIG. FIG. 6 is a block diagram of the cue signal generator in the cue signal recording apparatus of this invention.

In FIG. 6, 2 is a 7.2 kHz clock oscillator, and the output of this clock oscillator 2 is sent to a queue signal waveform memory section 3. When the clock signal from the clock oscillator 2 is sent to the queue signal waveform memory section 3, data is continuously outputted from the queue signal waveform memory section 3.

When writing, the queue signal fundamental wave 1 shown in FIG. 5 is sampled (A/D converted). In this case, as shown in Figure 7, the QUE signal fundamental wave 1 is made into 4 waves of 100Hz, and it is divided into 64 waves.
The waveform is divided into 316 parts in total, and the height of the waveform at that point is converted into an 8-bit digital value. The data sampled in this manner is written as a queue signal waveform into the queue signal waveform memory section 3 shown in FIG.

Next, when reading out the queue signal waveform written in this queue signal waveform memory section 3, in order to faithfully reproduce the above-mentioned 100Hz, one point is read out at 0.14ms using a 7.2kHz clock signal. . In this case, when the digital/analog (hereinafter referred to as D/A) converter 4 in FIG.
The waveform shown in the figure can be obtained.

The cue signal fundamental wave read out by the D/A converter 4 is sent to a signal amplifier 5. By shaping and amplifying the waveform in the signal amplification section 5, a cue signal as shown in FIG. 9 is reproduced and outputted to the output terminal 6.

The queue signal obtained in the above manner is the 10th queue signal.
The signal is sent to a recording device 8 in the cue signal recording device of this invention shown in the figure. In FIG. 10, the overall configuration of the queue signal generator shown in FIG. 6 is indicated by reference numeral 7. The cue signal obtained by the cue signal generator 7 is transmitted to the recording device 8.
The narration from the narration generator 9 is sent to the R (right) channel of the
It is configured to be sent to the L (left) channel of .

FIG. 11 shows a recording format for recording by the recording device 8. In the figure, numeral 10 indicates a recording tape, and this recording tape 10 is assumed to be fed in the direction of arrow A. The track 10L of the L channel of this recording tape 10 contains the narration N ₁ from the narration generator 9 in FIG.
N ₂ ,... are recorded and cue signals Q ₁ , Q ₂ , Q ₃ ,...
is track 10 of the R channel of recording tape 10.
The narrations N ₁ , N ₂ , N ₃ , . . . are recorded between each narration.

Then the narrations N ₁ , N ₂ , N ₃ ,
If the recording tape 10 on which the queue signals Q ₁ , Q ₂ , Q ₃ , etc. You can search.

At this time, as is clear from FIGS. 5 and 10, in the cue signal, the cue signal fundamental wave 1
Since the high frequency signal is made to be 2 times to 16 times higher before and after, the energy of this high frequency waveform part is small, and damping does not occur when recording and playing back the queue signal, making it possible to record and play back the queue signal faithfully. It can be carried out. This eliminates address selection errors in narrations including fast forward searches and fast backward searches.

[Effect of idea]

As described above, according to the cue signal recording device of this invention, the leading edge of the cue signal fundamental waveform component is converted into half waves of frequency components 16 times, 8 times, 4 times, and 2 times the cue signal fundamental waveform component. At the same time, the trailing edge of the cue signal fundamental wave is successively synthesized with half-wave waveforms of frequency components 2 times, 4 times, 8 times, and 16 times the cue signal fundamental wave. By creating a signal waveform and recording this cue signal waveform in front of each narration on a track on a recording tape that is different from the narration, the front and rear of the cue signal will be in a zero-cross state during recording and playback, and damping will occur. Waveforms no longer occur. This eliminates mistakes in selecting narration addresses.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the cue signal waveform when it is recorded on a recording tape and there is no damping, Figures 2 to 4 are diagrams each showing the waveform of the queue signal where damping occurs, and Figure 5 is the queue signal of this invention. A waveform diagram showing the queue signal waveform in the generator,
FIG. 6 is a block diagram showing an embodiment of the cue signal generating device of this invention, and FIG. 7 is an explanatory diagram of sampling of the cue signal to be stored in the cue signal waveform memory section in the cue signal generating device of FIG. 6. , FIG. 8 is a signal waveform diagram read out from the queue signal waveform memory section in the queue signal generator and converted into an analog signal; FIG. 9 is a diagram showing the queue signal waveform output from the queue signal generator; FIG. 10 is a block diagram illustrating the recording of cue signals by the cue signal generator of this invention, and FIG. 11 is a diagram showing the recording format of cue signals and narration by the cue signal generator of this invention. 2... Clock oscillator, 3... Queue signal waveform memory section, 4... D/A conversion section, 5... Signal amplifier, 7... Queue signal generator, 8... Recording device,
9... Narration generator, 10... Recording tape.

Claims (1)

[Scope of utility model registration request] In a cue signal generation device that generates a cue signal for searching the recorded portion of a recording tape, 16 of the cue signal fundamental wave is placed in front of the cue signal fundamental wave.
The half-waves of the frequency components of 2 times, 8 times, 4 times, and 2 times are continuously synthesized, and each half wave of the frequency components of 2 times, 4 times, 8 times, and 16 times is added to the rear of the above-mentioned cue signal fundamental wave. A cue signal generator that generates cue signals by continuously synthesizing them.