JPS6227707B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stop instruction signal detection method suitable for learning machines and the like that automatically stops a playback mechanism based on a stop instruction signal recorded in advance on a recording medium.

Generally, after a learning machine presents a problem by voice, a stop instruction is given using a blank period or a chime, and the learner then manually stops the learning machine and answers the presented problem. After thinking, the learner listens to the next answer that comes from the learning machine and compares it with his own answer to understand the problem. This can interfere with learning. Therefore, various stop instruction signal detection methods have been proposed in the past, in which a stop instruction signal is recorded in advance on a recording medium, and the learning machine is automatically stopped by detecting this signal. For example, (1) a specific single frequency in an audio signal is used as a stop instruction signal, and the detection device includes a band elimination filter for eliminating the specific single frequency, and a band pass that passes the specific single frequency. A system that consists of a filter and a logic circuit that logically processes the outputs from both filters to discriminate between a general audio signal and a stop instruction signal (Japanese Patent Publication No. 1973-29735), (2) in the general audio band. A method in which a low frequency signal, for example, a specific single frequency signal of 20 Hz, is pre-recorded on a recording medium at a level higher than the general audio level, and this is used as a stop instruction signal (Japanese Patent Publication No. 48-24529), (3 ) A method in which a pulse signal whose reproduced waveform has only one polarity is recorded as a control signal, and this control signal is detected separately from the audio signal (Japanese Patent Application Laid-Open No.
50-81508), etc.

However, in methods (1) and (2), there may be a specific frequency component used as a stop instruction signal in the general audio signal, and it may be detected as a stop instruction signal even though it is not a stop point. In addition, in method (3),
If a dubbing process is included in the middle, a pulse signal of opposite polarity is added during dubbing, resulting in a waveform that vibrates in both directions during final playback, making it impossible to obtain the desired signal waveform.

An object of the present invention is to use a signal of an arbitrary frequency within the audible frequency range as a stop instruction signal, which is higher than the level of a general audio signal, and continues for a certain period of time, to detect the signal of this arbitrary frequency, and to detect the level of the signal. It is an object of the present invention to provide a stop instruction signal detection method which solves the above-mentioned problems by checking the duration of the signal and determining the duration of the stop instruction signal if it is a predetermined value.

To briefly explain the principle of the stop instruction signal detection method in this invention, it is extremely rare for a signal of a considerably high level to exist continuously for a considerable length of time in an analog signal such as voice or music. Therefore, such a signal, that is, a signal that is higher in level than a general audio signal, etc. and continuous for a considerably long time, is used as a stop instruction signal, and its level and duration are checked to determine a predetermined value. By detecting whether or not this is the case, a highly reliable stop signal can be obtained.

Embodiments of the present invention will be described below based on the drawings. FIG. 1 shows a circuit when the stop instruction signal detection method of the present invention is applied to a learning machine with an automatic stop device. Now, the second
By pre-recording a signal at an arbitrary frequency within the audible frequency range, as shown in A in the diagram, at a level considerably higher than the general audio level for a certain amount of time, the magnetic head 1 will be A signal similar to this is detected, and a signal as shown in A in FIG. 2 is outputted through the preamplifier 2. The output of the preamplifier 2 is adjusted to an appropriate signal level by the AGC equipped amplifier 3 so that the stop instruction signal is not jarring, and then passed through a variable resistor 4 and amplified to an appropriate power level by the main amplifier 5. and is converted into audio by the speaker 6. The output of the preamplifier 2 is input to a rectifier/integrator 7 where it is rectified and integrated, and converted into a signal with a waveform as shown in FIG. 2B. The signal output from the rectifier/integrator 7 is input to a comparator 8 whose signal level is preset to V, and if the level of the input signal is V or higher, a waveform as shown in C in FIG. 2 is generated. signal,
That is, the comparator 8 outputs a signal having a pulse width corresponding to the time when the level of the input signal is equal to or higher than V. At the same time as the signal is output from the comparator 8, the monomulti 9 is activated, and a pulse of positive polarity and pulse width _T1 is output from the monomulti 9. The width T ₁ of this pulse, that is, the time constant of the monomulti 9, is set to a value large enough to cover a single high-level signal in the audio signal. The output of the monomulti 9 is negated by the NOT circuit 10, converted into a waveform as shown in D in FIG. 2, and then inputted to one input terminal of the AND circuit 11. And this AND circuit 1
The output of the comparator 8, which has been slightly delayed by the delay circuit 12 and becomes a signal as shown in FIG. The pulse shown in F of
It is output from the AND circuit 11. This AND circuit 1
The output from 1 is input to the monomulti 13, and the output from the 2nd
As shown in G in the figure, a signal with a pulse width T ₂ is generated when the output of the AND circuit 11 falls. This pulse width T ₂ is selected so that the falling point of this pulse is slightly later than the end of the stop instruction signal, so that the reproduction mechanism cannot be stopped until the stop instruction signal has completely ended. can. The output from the monomulti 13 is the second one with the same time width T ₃ as the time T ₃ required to control the drive circuit of the reproduction mechanism.
The signal is input to the monomulti 14 which generates a pulse as shown by H in the figure, and at the falling edge of the pulse from the monomulti 13, the monomulti 14 generates a drive circuit control signal, that is, a stop signal.

Next, another embodiment of the present invention will be described based on FIG. Components in FIG. 3 that are numbered the same as those in FIG. 1 have the same functions and effects, so their explanations will be omitted. Now, a plurality of arbitrary frequencies F ₁ , F ₂ , F ₃ within the audible frequency range as shown in A of FIG. 4 are placed at a predetermined location on the magnetic recording medium.
If you pre-record the signal formed by, for example, a chime sound at a level higher than the general audio level,
A signal similar to this is detected by the magnetic head 1 during reproduction as well. This detected signal is passed through a preamplifier 2, then inputted to a rectifier/integrator 7, where it is rectified and integrated, and converted into a signal with a waveform as shown in FIG. 4B. This signal is input to a comparator 8 whose signal level is preset to V, and if the level of the input signal is V or higher, a signal with a waveform as shown in C in FIG. 4 is generated, that is, the level of the input signal is The comparator 8 outputs a signal having a pulse width corresponding to the time when V is greater than or equal to V. At the same time as the signal is output from the comparator 8, the monomulti 9 also operates, and a pulse of positive polarity and pulse width T ₁ is output from the monomulti 9. The width T ₁ of this pulse, that is, the time constant of the monomulti 9, is set to a value large enough to cover a single high-level signal in the audio signal. mono multi 9
The output of is negated by the NOT circuit and becomes D in Figure 4.
After being converted to the waveform shown in , AND circuit 1
It is input to one input terminal of 1. And this
The delay circuit 1 is connected to the other input terminal of the AND circuit 11.
The output of the comparator 8, which has been slightly delayed in step 2 and becomes a signal as shown in E in Fig. 4, is input, and the AND of both input signals is taken to produce a pulse as shown in F in Fig. 4. Output from the AND circuit 11,
This output is input to the counter 15.

Further, the output from the comparator 8 is input to the monomulti 16, and at the rising edge of the output pulse of the comparator 8, the pulse width T ₂ is
The monomulti 16 outputs pulses as shown in FIG. This pulse width _T2 is set to be large enough to continue until a point slightly after the point in time when all stop instruction signals are completed. The pulse output from the monomulti 16 is input to the enable terminal of the counter 15, and
is kept in the enabled state, and when the count value of the counter 15 reaches "3" while this pulse continues,
A pulse as shown at H in FIG. 4 is output from the counter 15 and input to one input terminal of the AND circuit 17. In addition, the output from the monomulti 16 is input to the other input terminal of the AND circuit 17,
The AND of both signals is taken, and at the falling edge of the pulse output from the AND circuit 17, that is, at the falling edge of the pulse from the counter 15 shown at H in FIG. 4, the drive circuit of the reproduction mechanism is activated. It is input to the monomulti 18 which generates a pulse as shown in I in FIG. 4 with a time width T ₃ equal to the time required for control. The output pulse from the monomulti 18 is also input to the reset terminal of the counter 15 to reset the counter 15.

In this embodiment, the stop instruction signal can be formed by a chime sound, so there is no audible discomfort, and the stop instruction signal is generated when a signal of a specified level or higher is input three times within a specified time. It is highly reliable because it is used as a criterion for determining whether it is a signal or not. Also in this embodiment, since the control signal I that controls the drive circuit of the reproducing mechanism is output a little later than the end of the stop instruction signal, the reproducing mechanism is stopped only after the stop instruction signal has completely ended. can be done.

As described above, in the stop instruction signal detection method of the present invention, it is not necessary to specifically determine the frequency of the signal used as the stop instruction signal, so it is possible to use an easy-to-hear sound, such as a chime sound. Furthermore, in the present invention, the stop signal for stopping the drive system is generated after the stop instruction signal has completely ended, and a slight time interval is provided between the end point of the stop instruction signal and the generation point of the stop signal. Therefore, it is possible to prevent the inconvenience that the stop function is activated before the stop signal is finished, and the next time the motor is driven, the stop instruction signal appears first, is detected, and is judged as the stop instruction signal again. . Furthermore, since the present invention uses a stop instruction signal that has a higher level and a considerably longer duration than a general audio signal, it is more reliable than the conventional stop instruction signal detection method, and is a learning machine. It is extremely suitable for applications such as

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a stop instruction signal detection method in a learning machine with an automatic stop mechanism, etc., showing a first embodiment of the present invention, and FIG. 2 shows waveforms at each part shown in FIG. This is a timing chart to illustrate. FIG. 3 is a circuit diagram of a stop instruction signal detection method in a learning machine with an automatic stop mechanism, etc., showing a second embodiment of the present invention, and FIG. 4 shows waveforms at each part shown in FIG. This is a timing chart to illustrate. 1...Playback head, 2...Preamplifier, 3...
Amplifier with AGC, 4... Variable resistor, 5... Main amplifier, 6... Speaker, 7... Rectifier/integrator, 8... Comparator, 9... Mono multi, 1
0...NOT circuit, 11...AND circuit, 12...
Delay circuit, 13, 14...Mono multi, 15...
Counter, 16...Mono multi, 17...AND
Circuit, 18...Mono multi.

Claims (1)

[Claims] 1. A recording medium that is pre-recorded at a predetermined location on the recording medium as a stop instruction signal with a signal that is held at a level higher than the general audio signal level for a certain period of time at any frequency within the audible frequency range, and this recording medium. a rectifier/integrator that shapes the waveform of the reproduced signal; a stop instruction signal detection means that compares the waveform-shaped signal with a preset reference level and detects only signals higher than this reference level; Continuation time determining means for determining whether or not the signal continues for a predetermined time or longer; and a duration determining means for determining whether or not the signal continues for a predetermined time or longer; 1. A stop instruction signal detection method for a learning machine with an automatic stop device, etc., comprising automatic stop signal generation means for generating a stop signal for stopping.