JPH0239035B2 - - Google Patents

Abstract

PURPOSE:To decrease a reproduction speed while maintaining a natural sound, by storing a signal, reproduced at a speed 1/n as high as a tape speed in recording, on a recording element, by reading the signal at an (n)-fold speed and repeatedly voicing it (n) times, and then reproducing one next cycle. CONSTITUTION:The speed of a tape driving motor 1 is set a half that in normal reproduction. A reproduction output from a reproucing head 3 is stored in a constant-speed memory 6 through an amplifier 4 and an AD converter 5. The output of this constant-speed memory 6 is sent a constant time after the start of the storage at a period a half that in reproduction. In the 1st one cycle, it is passed through a fundamental-wave gate 7 as it is and then reconverted into an analog signal by a DA converter 10. When a zero potential and a change direction are detected from a voice waveform by detecting circuits 13 and 14, a signal which has the same waveform with said signal is outputted as a replication signal from a modulative memory 8. The outputs of the detecting circuits 13 and 14 close a gate 7 and open a gate 9, so the replication signal is sent to the DA converter 10, thereby repeating the same waveform.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention is an audio system that reproduces audio slowly without changing the basic audio spectrum when playing hearing lessons using a tape recorder for language education. The present invention relates to a playback device.

``Prior Art'' Generally, when practicing a language, if the tape is being played too fast and it is difficult to hear the correct pronunciation, the playback speed is slowed down. In such cases, I usually reduce the playback speed to 20
By just slowing it down by about 50%, it sounds like it's 50% slower.

``The problem that the invention aims to solve'' However, the current method is not slowing down so much that it is still difficult to hear the sound clearly. Moreover, if you try to slow down and listen more slowly, the tone will naturally change, making it even harder to hear than normal.

The present invention has been made to solve these conventional problems.

"Means for Solving the Problems" The present invention provides an A/D converter that converts an analog audio signal reproduced at a speed of 1/n of the normal speed into a digital audio signal, and a A constant speed memory that is combined and outputs the stored contents by n times, a fundamental wave gate that is directly connected to the constant speed memory, and a repetitive wave gate that is connected to the constant speed memory via a variable length memory. , a detection circuit coupled to the constant-speed memory and detecting the zero potential and change direction of the low-band spectrum from the output signal thereof, and controlling the variable length memory on and off using the detection signal; a switching means for alternately switching the fundamental wave gate and the repetitive wave gate; a D/A converter that couples the outputs of the fundamental wave gate and the repetitive wave gate into a line and returns them to an analog signal; The device is equipped with a speaker for reproducing the output of the /A converter.

``Function'' The reproduced sound is once stored in the memory, and one cycle is when the low band spectrum of the reproduced sound crosses at 0 potential.The fundamental wave is first reproduced, and the same cycle is recalled from the memory again for repeated reproduction. teeth,
By temporarily stopping the playback of the next cycle, the playback speed is halved. As a result, the audio spectrum can be slowed down without changing it, so the reproduction is natural and can be achieved with relatively simple circuitry.

“Embodiment” An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, where 1 is a tape drive motor with 1/n rotation (n=1, 2,...)
It can be changed to 2 is a magnetic tape, and 3 is a magnetic head. This magnetic head 3 includes an amplifier 4, an A/D (analog/digital) converter 5,
It is sequentially coupled to constant speed memory 6. This constant speed memory 6 is directly coupled to the fundamental wave gate 7, and a variable length memory 8 whose memory length can be changed.
These gates 7 and 9 are again connected in a line and are coupled to a speaker 12 via a D/A (digital/analog) converter 10 and an amplifier 11.

The constant speed memory 6 also includes a zero potential detection circuit 1 for detecting the point where the low band spectrum crosses the zero potential.
3 and a change direction detection circuit 14 for detecting the change direction of the intersection point are connected in parallel to each other, and the output terminals of these detection circuits 13 and 14 are connected to the variable length memory 8 and a repeating flip-flop as a switching means. 15. The output terminal of this repeating flip-flop 15 is connected to the fundamental wave gate 7.
Furthermore, the Q output terminal is coupled to the repetitive wave gate 9.

Next, the action of regeneration according to the present invention will be explained.

First, reduce the speed of tape drive motor 1 to 1/2 of the normal speed.
Make it. Then, under normal conditions, the output of the amplifier 4 should have an output waveform A as shown by the solid line in Figure 2a (the period of one cycle at this time is T ₀ ), but it has a waveform of 1/2. Since this is the speed, the output waveform is as shown by the solid line (period 2T ₀ ). The audio output signal indicated by the solid line is converted by the A/D converter 5 into a pulse signal having, for example, a 4-bit configuration as shown in FIG. From this constant speed memory 6, at _t1 , a certain time after the start of storage _t0 , as shown in FIG _. A pulse signal is output when T ₀ is reached.

Here, the first cycle _T0 passes through the fundamental wave gate 7 and is returned to the analog signal C as shown in FIG. 2e by the D/A converter 10. Also, the same signal from memory 6 is stored in variable length memory 8.

Next, at _t2 , when _T0 has elapsed from _t1 , the detection circuit 13 detects zero potential and the direction of change from the audio waveform.
14, the memory 8 outputs a repetition pulse signal as shown in FIG. 4d which is exactly the same as that shown in FIG. 4c but delayed by T ₀ . At the same time, the output signals of the detection circuits 13 and 14 change from the output to the Q output, closing the gate 7 and opening the gate 9. This time, a repetitive pulse signal is sent to the D/A converter 10, as shown in FIG. The result is the analog signal D shown in .
In other words, the same waveforms C and D are repeated.

When the audio signal reaches zero potential, the repetitive wave is stopped again and the fundamental wave is output. In this way, the first fundamental wave, its repetition wave, the second fundamental wave, its repetition wave, .

Next, Figure 3 shows the second mode that reduces the playback speed to 1/3.
An example is shown. In this example of Fig. 3, the first
To the circuit shown in the figure, a memory 16 for delaying the repetition wave by one cycle and a gate 17 for re-repetition waves are added, and a flip-flop circuit shown in FIG. 15 to shift register 15a.

With this configuration, if the speed of the tape drive motor 1 is reduced to 1/3 of the normal speed, the speed of the tape drive motor 1 is reduced to 1/3 of the normal speed.
It is repeated one time at a time and the playback speed is slowed down to 1/3.

In the above embodiment, a tape recorder is used, but a disk recorder may also be used. In addition to magnetic reproduction, methods using light, piezoelectricity, etc. may also be used.

"Effects of the Invention" Since the present invention employs the device as described above, it is possible to delay the reproduced sound by 1/n without changing the basic audio spectrum. In other words, there is no change in tone and the playback speed can be slowed down with extremely natural sound. Furthermore, the circuit configuration is relatively simple and can be provided at low cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a first embodiment of an audio reproducing apparatus according to the present invention, FIG. 2 is a diagram of output waveforms of each part, and FIG. 3 is a block diagram of a second embodiment of the present invention. 1... Drive motor, 2... Magnetic tape, 3...
Magnetic head, 4...Amplifier, 5...A/D converter, 6...Constant speed memory, 7...Fundamental wave gate,
8, 16...Variable length memory, 9...Repetitive wave gate, 10...D/A converter, 11...Amplifier, 1
2...Speaker, 13...Zero potential detection circuit, 14
. . . Change direction detection circuit, 15, 15a . . . Switching means, 17 . . . Re-repetition wave gate.

Claims (1)

[Claims] 1. An A/D converter that converts an analog audio signal reproduced at a speed 1/n of the normal speed into a digital audio signal; a constant-speed memory that outputs a signal multiplied by n; a fundamental wave gate directly connected to the constant-speed memory; a repetitive wave gate connected to the constant-speed memory via a variable-length memory; and the constant-speed memory. a detection circuit coupled to the detection circuit, which detects the zero potential and change direction of the low-band spectrum from the output signal thereof, and controls the variable length memory on and off using the detection signal; a switching means that alternately switches the repetitive wave gate; a D/A converter that combines the outputs of the fundamental wave gate and the repetitive wave gate into a line and returns them to an analog signal; An audio reproduction device comprising a speaker for reproducing output. 2. In claim 1, a repeat wave gate is further coupled to the output end of the variable length memory via a variable length memory, and the fundamental wave gate, the repeat wave gate, and the repeat wave gate are connected to the output end of the variable length memory via the variable length memory. An audio reproduction device in which a repetitive wave gate is sequentially switched using a shift register as a switching means.