JPS6016014B2 - Signal detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting a control signal (stop signal) in a learning machine, etc., and is particularly characterized in that an audio signal and a control signal can be reliably distinguished. It is something to do.

Currently, the learning machines in general use are instructed to stop by a blank time or a chime after presenting the problem by voice, and the learner manually stops the learning machine according to the instruction, and after analyzing the problem, The learning machine is configured to operate by pressing the play button again, listen to the next answer, and compare it with your own answer to understand the problem. However, if the learner did not manually stop the learning machine, the answer could be heard, hindering learning.

In order to solve the above-mentioned shortcomings in the prior art, the present applicant has made it possible to automatically stop the learning machine by a stop instruction signal, and the learner does not have to judge the stop signal each time to stop the learning machine. He proposed a learning machine that did not have a 1989 learning machine (see, for example, Japanese Patent Publication No. 48-29735).

However, in the learning machine previously proposed by the applicant, the stop instruction signal consists of only one frequency, so if there is a signal with the same frequency as the stop instruction signal in the audio signal, the old voice signal frequency If the stop signal is recorded for a long time or if the stop signal is recorded for a long time, the playback may end up stopping again when the playback is restarted.

The present invention has been made to improve the drawbacks of the above-mentioned conventional techniques, and in particular, to obtain an automatic stop signal with a simple structure and high reliability by using two different frequencies as stop signals. This is what I did.

FIG. 1 is an electrical circuit diagram for explaining an embodiment of the automatic stop signal regeneration method according to the present invention, and FIG. 2 is an electrical signal waveform diagram for explaining the operation of FIG. 1.

According to the present invention, an automatic stop signal consisting of two signals F, , F2 having different frequencies is placed at a predetermined position on the audio signal track of the recording medium 1 (the position where the reproduction operation is stopped), as shown in FIG. 2a. is recorded. During playback, the audio signal on the recording medium 1 is transferred to the magnetic head 2 in the same manner as in normal playback operation.
, a preamplifier 3, a main amplifier 4, and a speaker 5. When the reproducing operation progresses and an automatic stop signal F,, F2 as shown in FIG. 8, the second through the waveform shaping circuit 9 etc.
The signal is input to the set terminal of the RS flip-flop circuit 10 shaped into a waveform as shown in FIG. b. On the other hand, frequency F
A band pass filter 6a that passes only the frequency F2 of the signal of No. 2, a rectifier circuit 7a, an integrating circuit 8a, and a waveform shaping circuit 9a.
etc., the RS is shaped into a waveform as shown in Figure 2c.
It is input to the reset terminal of the flip-flop circuit 10. Therefore, the output signal waveform of the RS flip-flop circuit 10 becomes as shown in FIG.
Monostable multi 11 has 1 RS flip-flop circuit 10
When set/reset is performed twice, it operates and generates a high level output for a time T (see FIG. 2e). The output of this monostable multi 11 opens the AND gate circuit G, and at the same time the counter 12 is reset (Fig. 2g).
reference). Therefore, thereafter, each time the flip-flop circuit 10 operates, its output signal is supplied to the counter 12 through the AND gate circuit G, and counted by the counter 12. When the counter 12 counts a preset number of pulses (see FIG. 2 f), its output becomes high level (see FIG. 2 g). When the output of the counter 12 becomes high level, the AND gate circuit G2 is activated by the /, i level output of the counter 12 and the /, i level output of the monostable multi 11 (see Fig. 2 h), and the output of the monostable multi 11 is activated. When the signal becomes low level, the monostable multi 13 operates and generates a stop instruction signal for the time T2 required to stop the regeneration operation (see Figure 2 i), and the regeneration operation is stopped by this signal. . As explained above, the present invention obtains a stop signal by alternately detecting two signals with different frequencies, but when signals of different frequencies are alternately detected in signals such as voice and music, Since it is extremely rare for a stop signal to occur many times, if a stop signal is obtained as in the present invention, there is almost no probability of malfunction, and reliability can be significantly improved.

For example, even if the frequency component of the F, signal or F2 signal is recorded many times in the audio signal,
Monostable multi 13 does not operate with only signals, and F,
Even if the frequencies of the signal and F2 signal are recorded randomly, the F, signal and F2 signal are included many times (three times in the example in Figure 2) during the L time determined by the monostable multi 11. Since this rarely happens, the asodo gate circuit○
The logical product of 2 does not hold, and the monostable multi 13 does not operate. Furthermore, if the F signal and the F2 signal are recorded for a long time, the counter 12 will not count a predetermined number of times, three times in the example of FIG. Because it is not possible, the logical product of AND gate circuit ○2 is almost never satisfied.
doesn't even work. FIG. 3 is an electrical circuit diagram for explaining another embodiment of the present invention, and FIG. 4 is an electrical signal waveform diagram for explaining the operation of FIG. 3. This circuit is different from the embodiment shown in FIG. 1 in that the counter 12 in the embodiment shown in FIG. According to the embodiment shown in FIG. 3, the monostable multi 14 operates when the output of the RS flip-flop circuit 10 is detected twice, and keeps one input of the AND gate circuit G2 at a high level for a time T2. (See Figure 4g). The band gate circuit G2 is a monostable multi 1 1
When the outputs of ). The embodiment shown in FIG. 3 operates if the F,, F2 signal is included even once within the time period T, so it is less reliable than the embodiment shown in FIG. Although it is slightly inferior in this respect, it has the advantage that the circuit configuration is simple and inexpensive. In addition, in the above explanation, an example in which the present invention is applied to a learning machine has been described, but the present invention is not limited to a learning machine, and is not limited to a control signal for randomly searching audio information such as an audio information file system. It is easy to understand that it can also be used as As is clear from the above description, according to the present invention, a highly reliable automatic stop signal can be obtained with a simple and inexpensive configuration.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram for explaining one embodiment of the present invention, FIG. 2 is an electrical signal waveform diagram of the main part, and FIG.
The figure is an electric circuit diagram for explaining another embodiment of the present invention, and FIG. 4 is an electric signal waveform diagram of the main part thereof. 1... Recording medium, 2... Playback head, 3...
...Preamplifier, 4...Main amplifier, 5...Speaker,
6, 6a... Band pass filter, 7, 7a... Rectifier circuit, 8, 8a... Integrating circuit, 9, 9a...
... Waveform shaping circuit, 10...RS flip-flop circuit, 11, 13, 14... Monostable multi, 12... Force counter. Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] 1. Two signals F_1 and F_2 having different frequencies are alternately recorded as control signals on the same track as the audio signal track, and during playback, the control signal is detected when the signals F_1 and F_2 are detected alternately. A signal detection method featuring: