JP2000224687A - Signal transmitter and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording medium which records the audible band signal of sharp directivity, and a compact and inexpensive signal transmitter capable of reproducing the recording medium and discharging the audible band signal in simple configuration. SOLUTION: This device 1 is provided with a signal generating part 2 for outputting a modulated signal, for which the ultrasonic band signal of ultrasonic frequency is modulated while using the audible band signal of audible frequency, and an echo sounder transmission part 3 for discharging the modulated signal of the signal generating part 2 in the air or in the water as an ultrasonic wave. In this case, the signal generating part 2 is provided with a reproducing device 5 for reproducing a recording medium 4 on which the modulated signal is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a modulation signal obtained by modulating an ultrasonic frequency band signal (hereinafter referred to as an ultrasonic band signal) using an audio frequency band signal (hereinafter referred to as an audible band signal). The present invention relates to a signal transmitting device that emits air or water and a recording medium on which the modulated signal is recorded.

[0002]

2. Description of the Related Art In museums and exhibitions, it may be necessary to transmit audio signals such as voice (audible band signals) to a limited space in order to explain a specific exhibit. As one means, a signal transmission for transmitting an audible band signal as a carrier using an ultrasonic band signal as disclosed in the Journal of Electroacoustic Research, "Application of Nonlinear Parametric Action to Speaker" (January, 1982). There is a device.

FIG. 6 is a schematic diagram showing a schematic configuration of a conventional signal transmission device. In FIG. 6, the signal transmission device 1
Audible band signal source 8, equalizer 9, carrier generator 11,
A signal generator 2 having a modulator 10, a power amplifier 6,
And a wave transmitting unit 3 having a converter 7. The frequency characteristic of the audible band signal output from the audible band signal source 8 is corrected by the equalizer 9, and the audible band signal is input to the modulator 10.
The modulator 10 amplitude-modulates a carrier (for example, a signal having a frequency of 40 kHz) in the ultrasonic band output from the carrier generator 11 using a signal output from the equalizer 9 and outputs the modulated signal to the transmission unit 3 as a modulation signal. I do. The power transmitting unit 3 power-amplifies the modulated signal output from the signal generating unit 2 by the power amplifier 6, and then emits the modulated signal into the air or water as an ultrasonic wave from a converter 7 such as a piezoelectric element.

The sound pressure of the ultrasonic wave output from the transmitting unit 3 is
Since the sound pressure is very high at 120 dB or more, the ultrasonic wave is demodulated due to the nonlinearity of air while propagating in the air, and an audible band signal is reproduced.

In the signal transmitting apparatus 1, since ultrasonic waves having sharp directivity are used, the state becomes equal to a state in which an array of speakers is formed in the air, and the directivity of an audible band signal reproduced in the air is adjusted. The audible band signal can be transmitted only to a limited space.

[0006] Instead of utilizing the non-linearity of air as in the signal transmitting device 1 described above, an apparatus utilizing an electroacoustic transducer such as an earphone transmits an ultrasonic band signal modulated by an audible band signal. A device that emits the ultrasonic band signal from the wave unit 3 into the air, receives the ultrasonic band signal with an ultrasonic microphone, converts the signal into an electric signal, demodulates the electric signal, and obtains an audible band signal using an electroacoustic converter such as an earphone. is there.

[0007]

In a signal transmission device used for explaining a museum or an exhibition, etc., it is necessary to explain different contents for each exhibit. Is required. The above-described signal transmission device is expensive because it includes a carrier generation unit and a modulator, and using the same number of signal transmission devices as described will increase the cost.

Further, since the signal transmission device is provided with the amplitude modulator, a space for installing the signal transmission device is required, and the exhibition space in a museum or an exhibition may be limited.

The present invention provides a recording medium on which an audible band signal having a sharp directivity is recorded, and a small and inexpensive signal transmitting apparatus capable of reproducing the recording medium with a simple configuration and emitting the audible band signal. The task is to provide.

[0010]

According to a first aspect of the present invention, there is provided a signal generator for outputting a modulated signal obtained by modulating an ultrasonic band signal using an audible band signal, and a signal generator for outputting a modulated signal. In a signal transmitting device including a transmitting unit that emits sound waves into the air or water, the signal generating unit includes a reproducing device that reproduces a recording medium on which a modulated signal is recorded.

According to a second aspect of the present invention, there is provided a signal generator for outputting a modulation signal obtained by modulating an ultrasonic band signal using an audible band signal, and a modulated signal of the signal generator is transmitted as ultrasonic waves in the air or underwater. And a signal transmitting unit including a transmitting unit that emits a signal to the transmitter, wherein the signal generating unit synthesizes a plurality of modulated signals generated by modulating different types of ultrasonic band signals with different types of audible band signals. It is characterized by comprising a reproducing device for reproducing a recording medium on which a composite modulated signal is recorded.

According to a third aspect of the present invention, in the recording medium, a modulated signal obtained by modulating an ultrasonic band signal using an audible band signal with a high-frequency component emphasized is recorded.

According to a fourth aspect of the present invention, on a recording medium, a composite modulated signal obtained by combining a plurality of modulation signals obtained by modulating different types of ultrasonic band signals with different types of audible band signals is recorded. It is characterized by:

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram showing a schematic configuration of one embodiment of a signal transmission device according to the present invention. In FIG. 1, a signal transmitting device 1 includes a signal generating unit 2 and a transmitting unit 3.
And The signal generator 2 includes a reproducing device 5 that reproduces a recording medium 4 on which a modulated signal obtained by modulating an ultrasonic band signal with an audible band signal is recorded. In the present embodiment, the audible band signal is an audio signal which is information such as voice or music to be transmitted.

The recording medium 4 is a recording medium on which a modulation signal is recorded, and is an optical disk, a magneto-optical disk, a magnetic disk, a magnetic tape, a memory card, or the like. Playback device 5
Is a device capable of reproducing the recording medium 4.

The transmitting section 3 power-amplifies the modulated signal output from the signal generating section 2 by a power amplifier 6, converts the electric signal into an ultrasonic wave by a converter 7, and emits the ultrasonic wave into the air or water. As the converter 7, a converter of an electrodynamic type, an electrostatic type, a piezoelectric type, or the like is used.

FIG. 2 is an explanatory diagram showing a procedure for recording a recording signal on a recording medium used in the signal transmission device of the present embodiment. FIG. 3 is a schematic diagram for explaining a signal recorded on a recording medium reproduced by the reproducing device of the signal transmission device of the present embodiment. In FIG. 2, the audible band signal output from the audible band signal source 8 has its frequency characteristics corrected by an equalizer 9 and is input to a modulator 10. The equalizer 9 corrects the frequency characteristics so that the reproduced audible band signal has a desired frequency characteristic when the signal is received by a signal receiving device (not shown) and reproduced as an audible band signal.

The modulator 10 receives the audible band signal shown in FIG. 3A and the carrier (ultrasonic band signal) output from the carrier generator 11 shown in FIG. 3B. In particular, when a piezoelectric converter 7 is used as the converter 7 of the transmitting unit 3 shown in FIG. 1 and the resonance point is adjusted to the frequency of the carrier wave for the purpose of increasing the conversion efficiency, the modulated wave output from the modulator 10 Is attenuated, so that it is necessary to emphasize the high-frequency component of the signal in advance. Therefore, equalizer 9
By correcting the frequency characteristics of the signal to obtain a modulated signal, a signal having flat frequency characteristics can be obtained when a signal received by a signal receiving device (not shown) is demodulated.

As a carrier, a signal having a frequency higher than the audible band (for example, 20 kHz or more) is used.
Modulates the carrier output from the carrier generator 11 using the signal output from the equalizer 9 to obtain a modulated signal shown in FIG. The modulated signal is recorded on the recording medium 4 by the recording device 12.

As the recording medium 4, for example, 100 kHz
Digital versatile disk (DVD: Digital Versatile Diode) capable of recording signals up to near z
sk). When a signal is recorded on a DVD, a modulation signal obtained by modulating an ultrasonic band signal with an audible band signal corrected by the equalizer 9 is converted into a digital signal, and an error correction code is added, a synchronization signal is added, and modulation is performed on the DVD. Encoding is performed according to a format determined in the disk system and recorded on the recording medium 4.

The recording medium 4 on which the signal has been recorded in this manner is reproduced by the reproducing device 5 of the signal generator 2 shown in FIG. 1, and is input to the wave transmitter 3 as a modulated signal. here,
The recording medium 4 may be a write-once or rewritable recording medium.

As described above, the reproducing apparatus for modulating the ultrasonic band signal with the audible band signal to be transmitted and recording the modulated signal on the recording medium and reproducing the signal recorded on the recording medium is referred to as a signal generating section. The signal output from the unit is emitted into the air or water as ultrasonic waves by the transmitting unit. When the ultrasonic wave is emitted into the air, the ultrasonic wave is demodulated due to the non-linearity in the air, and becomes an audible band signal.

Therefore, in a museum, an exhibition, or the like, a signal transmitting device that emits a signal related to a description of a different content for each exhibit can be realized by a playback device having a simple configuration. The wave device can be inexpensive.

Further, since the signal transmitting device can use a small reproducing device without an amplitude modulator, the signal transmitting device itself can be downsized, and the exhibition space in a museum or an exhibition can be reduced. Can be wider.

In the above-described embodiment, one piece of information is recorded on the recording medium 4 of the signal transmitting device 1. However, different pieces of information may be recorded on different tracks. That is, when the signal transmission device 1 is used to explain the contents of exhibits such as museums and exhibitions, when the number of exhibits is large and the contents of explanation are different for each of the exhibits, different information (the contents of explanation that are different for each of the exhibits) ) Is recorded for each track to produce a recording medium 4. Then, each signal transmission device 1 reproduces a specific track (a track on which the information describing the content of each presentation) is recorded on the recording medium 4.

With this, it is not necessary to prepare the recording medium 4 for each exhibit having different explanation contents, and the explanation contents of the different exhibit are recorded on one recording medium 4 and the recording medium 4 is recorded.
Can be used for a plurality of signal transmission devices 1.

Another method of recording different information on the recording medium 4 is to modulate an ultrasonic band signal of a different frequency using a different audible band signal and to combine a signal obtained by combining a plurality of modulated signals on the recording medium 4. There is a way to record.

FIG. 4 is a schematic diagram for explaining the signal transmitting apparatus of the present embodiment and a signal receiving apparatus using the signal transmitting apparatus. FIG. 5 is a schematic diagram for explaining a composite modulated signal recorded on a recording medium reproduced by a reproducing device in the signal transmission device of the present embodiment. In FIG. 4, the signal transmitting device 1 includes a signal generating unit 2 including a reproducing device 5 and a transmitting unit 3 including a power amplifier 6 and a converter 7. The plurality of signal receiving devices 13a and 13b include converters 14a and 14b, demodulators 15a and 15b, and an output unit 1.
6a and 16b. In this embodiment, the output unit 16
Although a and 16b are speakers, the present invention is not limited to them, and headphones and earphones may be used.

In the signal transmitting apparatus 1 of the present embodiment, ultrasonic band signals having different frequencies are modulated using different types of audible band signals, and a composite modulated signal obtained by combining a plurality of modulated signals is recorded. The recording medium 4 is reproduced.

Using an audible band signal A (for example, audio signal A) shown in FIG. 5A and an audible band signal B (for example, audio signal B) shown in FIG.
The ultrasonic band signals A and B having different frequencies shown in FIG. 5C and FIG. 5D are modulated. FIG.
When the ultrasonic band signal A shown in (b) is modulated by the audible band signal A shown in FIG. 5A, a modulated signal A shown in FIG. 5E is obtained. When the ultrasonic band signal B shown in FIG. 5D is modulated by the audible band signal B shown in FIG. 5B, a modulated signal B shown in FIG. 5F is obtained.

When the modulated signal A and the modulated signal B shown in FIGS. 5E and 5F are combined, a combined modulated signal shown in FIG. 5G is obtained. The composite modulated signal is recorded on the recording medium 4. This recording medium is reproduced by the reproducing device 5 of the signal transmitting device 1 shown in FIG. 4, and the combined modulated signal is emitted from the converter 7 of the transmitting unit 3 as an ultrasonic wave.

On the other hand, a signal receiving device 13 for receiving ultrasonic waves
Each of a and 13b includes a converter 14a or a converter 14b having a characteristic of receiving only an ultrasonic wave corresponding to the frequency of the ultrasonic band signal used for each modulation signal.

The signal receiving device 13a converts only the modulated signal A out of the composite modulated signal emitted from the signal transmitting device 1 into an electric signal by the converter 14a, demodulates the electric signal by the demodulator 15a, and outputs the signal to the output section 16a. Output as an audible band signal A.
Similarly, the signal receiving device 13b converts only the modulated signal B of the combined modulated signal emitted from the signal transmitting device 1 into the converter 13
4 and converts the signal into an electric signal.
6b is output as an audible band signal B.

As described above, by synthesizing and recording different types of audible band signals on one recording medium, the signal transmitting apparatus reproduces the recording medium and emits the composite modulated signal as ultrasonic waves. it can. The signal receiving device receives a signal obtained by modulating an ultrasonic band signal of a specific frequency with each converter, and outputs an audible band signal without being affected by other modulated signals included in the composite modulated signal. be able to.

For example, in the case of use in a museum or an exhibition, etc., a plurality of audible band signals in which the description of the contents of an exhibit is expressed in different languages are modulated with ultrasonic band signals of different frequencies, respectively, and a plurality of modulations are performed. The signals are combined and recorded on one recording medium. The signal transmitting device reproduces the recording medium. The signal receiving device is configured so that the transducers can receive different modulated signals. For example, in the signal receiving device A, a sound describing the exhibit in Japanese is output. The device B outputs a sound describing the exhibit in English.

As described above, a single signal transmitting device simultaneously emits a plurality of modulated signals having different contents, and a signal receiving device corresponding to each modulated signal receives each of the modulated signals. A plurality of types of audible band signals can be obtained from one recording medium and a signal transmission device. Therefore, when the contents of the description of the exhibit are expressed in different languages, it is not necessary to provide a plurality of devices for each exhibit, and it is possible to simplify the apparatus for explaining the contents of the exhibit and reduce the cost. Also, maintenance and the like become easy.

Further, it is not necessary to prepare a recording medium for each of different types of audible band signals, and audible band signals having different contents can be multiplexed and recorded on one recording medium. , The number of recording media can be reduced.

[0038]

According to the present invention, it is possible to provide a recording medium on which an audible band signal (audio signal) having sharp directivity is recorded. Further, it is possible to provide a small and inexpensive signal transmission device capable of reproducing a recording medium and emitting an audible band signal with a simple configuration. Further, it is possible to easily produce a recording medium on which different types of audible band signals are recorded.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of one embodiment of a signal transmission device of the present invention.

FIG. 2 is an explanatory diagram showing a procedure for recording a recording signal on a recording medium used in the signal transmission device of the embodiment.

FIG. 3 is a schematic diagram for explaining a signal recorded on a recording medium reproduced by a reproduction device of the signal transmission device of the present embodiment.

FIG. 4 is a schematic diagram for explaining a signal transmitting device of the present embodiment and a signal receiving device using the signal transmitting device.

FIG. 5 is a schematic diagram for explaining a composite modulated signal recorded on a recording medium reproduced by a reproducing device in the signal transmission device of the present embodiment.

FIG. 6 is a schematic diagram showing a schematic configuration of a conventional signal transmission device.

[Explanation of Signs] 1. Signal transmitting device, 2. Signal generating unit, 3. Transmitting unit, 4. Recording medium, 5. Reproducing device, 6, Power amplifier, 7, Converter , 8 ... Audio band signal source, 9 ... Equalizer, 10 ... Modulator, 11 ... Carrier generator, 1
2 ··· Recording device, 13a, 13b ··· Signal receiving device, 1
4a, 14b converter, 15a, 15b demodulator,
16a, 16b ... output unit.

Claims (4)

[Claims] A signal generator for outputting a modulated signal obtained by modulating an ultrasonic frequency band signal using an audible frequency band signal;
A signal transmitting unit that emits the modulated signal of the signal generating unit into the air or water as ultrasonic waves, wherein the signal generating unit reproduces a recording medium on which the modulated signal is recorded. A signal transmitting device comprising the device. 2. A signal generator for outputting a modulated signal obtained by modulating an ultrasonic frequency band signal using an audible frequency band signal;
A signal transmitting unit that emits the modulated signal of the signal generating unit into the air or water as ultrasonic waves, wherein the signal generating unit uses different types of audible frequency band signals to generate different types of ultrasonic signals. A signal transmitting device comprising: a reproducing device that reproduces a recording medium on which a combined modulation signal obtained by modulating a sound wave frequency band signal and combining a plurality of modulation signals generated is synthesized. 3. A recording medium wherein a high frequency component is emphasized and a modulation signal obtained by modulating an ultrasonic frequency band signal using an audible frequency band signal is recorded. 4. A recording medium characterized by recording a composite modulated signal obtained by combining a plurality of modulation signals obtained by modulating different types of ultrasonic frequency band signals with different types of audible frequency band signals.