JP2001005455A - Melody sound generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melody sound generating device capable of generating sound composed of plural music scales by a simple circuit as melody sound, and generating it in a sufficient volume and also high quality. SOLUTION: This melody sound generating device comprises a scale data generating circuit 1 for generating music scale data composed of predetermined bits based on a predetermined scale, a melody sound data creating circuit 2 for creating melody sound data composed of plural music scales by summing the plural highest bits of the music scale data generated by the music scale generating circuit 1, a DA converter 7 for converting digital data created by the melody sound data creating circuit 2 into an analog signal, and a piezo-electric buzzer 9 for generating sound by vibrating a piezo-electric vibrator 92 based on the output of this DA converter 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melody sound generator for generating a ring tone or a holding tone of a digital cellular phone or a PHS, and a simple melody sound built in a toy or the like. The present invention relates to a melody sound generating device that generates a melody sound having a musical scale.

[0002]

2. Description of the Related Art In recent years, digital mobile phones and PHSs have rapidly spread, and as a ring tone or the like for notifying a user of an incoming call, a mobile phone equipped with a melody sound generator using a melody sound has been proposed. Many are used.

A melody sound generator built in the above-mentioned portable telephone or the like is provided with a read-only memory storing data as it is or data after compression encoding.
Data is read from this read-only memory, and the read data is directly
Some are configured to output to an analog converter.
This device requires a read-only memory of about several tens of kilobytes, and has a problem that the circuit scale becomes large.

Further, in order to reduce the circuit scale, there is a portable telephone equipped with a melody sound generator having the same configuration as a tone generator for generating various single tones such as a busy tone. There is also a device that generates a melody sound using a piezoelectric buzzer that vibrates a piezoelectric vibrator by an applied voltage.

[0005]

However, a melody sound generator having the same configuration as the above tone generator or a melody sound generator using a piezoelectric buzzer generates only a main melody tone having a single scale. In fact, only a poor melody sound can be generated.

[0006] For a user, a ring tone or the like composed of a plurality of melody sounds that are usually heard as music or the like is desired. However, in order to create such a melody sound, a circuit scale is required. There was a problem of becoming larger. Also, as the circuit size increases, the power consumption also increases. However, when used in portable equipment, it is desired that power consumption be as low as possible.

Since the above-mentioned piezoelectric buzzer generates a lower volume than a speaker, it is necessary to use the buzzer so that the volume can be sufficiently secured. Therefore, the conventional piezoelectric buzzer generates a pulse signal based on the frequency of the sound, and vibrates the piezoelectric vibrator with the pulse signal to secure a sound volume. When the piezoelectric buzzer is driven by a pulse signal based on the frequency of a single musical scale, it can accurately follow the frequency. Therefore, when used for generating only the main melody tone composed of a single scale, a sound with little noise can be generated even when driven by a pulse signal.

However, if the piezoelectric buzzer is driven by a pulse signal based on the frequencies of a plurality of scales, the piezoelectric buzzer cannot accurately follow those frequencies. Therefore, the sound generated from the piezoelectric buzzer contains many unnecessary frequency components, that is, a lot of noise, and the sound quality deteriorates. Therefore, it is conceivable to avoid the deterioration of sound quality by driving the piezoelectric buzzer with the sound waveform itself having a predetermined frequency instead of driving the piezoelectric buzzer with a pulse signal. However, when the piezoelectric buzzer is driven by the sound waveform itself, there is a problem that the sound volume is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and provides a simple and low power consumption circuit utilizing a piezoelectric buzzer to sufficiently produce a melody sound composed of a plurality of musical scales. It is an object of the present invention to provide a melody sound generating device that generates a sound with high volume and good sound quality.

[0010]

A melody sound generating device according to the present invention is a melody sound generating device for generating a melody sound having a predetermined scale, wherein the melody sound generating device generates scale data including predetermined bits based on a predetermined scale. Generating means, melody sound data creating means for creating melody sound data composed of a plurality of scales by respectively adding upper predetermined bits of a plurality of scale data generated by the scale data generating means, and melody sound data creating means Digital-to-analog conversion means for converting the digital data created in
A piezoelectric buzzer for generating a melody sound by vibrating the piezoelectric vibrator based on an output of the analog converter.

Further, the melody sound data creating means may be configured to create melody sound data by adding the most significant bit of the scale data generated by the scale data generating means.

With the above configuration, a sound composed of a plurality of musical scales can be generated as a melody sound from a low-power-consumption piezoelectric buzzer. And this melody sound
It is not generated by driving a piezoelectric buzzer based on a pulse signal, but is generated by driving a piezoelectric buzzer based on an analog signal. Thus, the piezoelectric buzzer can accurately follow the frequencies of a plurality of scales, thereby suppressing noise and generating a melody sound with good sound quality. Further, since a melody sound is generated by a stepwise analog waveform obtained based on adding only upper predetermined bits of a plurality of scale data, a sufficient volume can be obtained. Higher-order predetermined bits, especially higher-order bits, with a large weight largely reflect the characteristics of the scale. Therefore, a melody sound is generated by an analog signal obtained based on the addition of the upper predetermined bits, so that a sound with high auditory quality can be generated as a melody sound.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
This will be described with reference to FIGS. Here, in the present embodiment, a melody sound generating device in which the scale of a melody sound composed of a main melody sound and a chord is programmed by a user will be described.

FIG. 1 is a circuit diagram showing a case where the melody sound generating apparatus according to the present invention is applied to a portable telephone or a PHS. This melody sound generator includes a scale data generation circuit 1, a melody sound data creation circuit 2, a sequence control circuit 3, a numeric keypad 4, digital / analog converters 6 and 7 (hereinafter referred to as "D / A converters 6 and 7"). Call.), Speaker 8,
Piezoelectric buzzer 9, audio encoding / decoding device 10 (hereinafter, referred to as
Called "voice CODEC10". ) And a transmission circuit 11.

The scale data generation circuit 1 generates scale data of the main melody and scale data constituting a chord. As shown in FIG. 2, a waveform memory 101, an address generator 102, and a gain adjustment circuit 103 generate the scale data. Be composed. In general, in consideration of the fact that 14-bit digital data is used as scale data used in mobile phones and the like, in the present embodiment, the scale data of the main melody and the scale data forming the code are all 14 bits.
Although the digital data is treated as digital data composed of bits, the present invention is not limited to this, and there is no problem even if the present invention is modified.

The waveform memory 101 stores data of one cycle of a single sine waveform. The address generator 102 converts the single sine wave data stored in the waveform memory 101 into sine wave data (14 bits) having different frequencies, ie, scale data, based on a command from the sequence control circuit 3. The address of the waveform memory 101 is designated so that the address can be sent to the address 103.
Here, the scale data has a higher weight as the bit is higher, and the weight of the most significant bit is the highest. For this reason, the most significant bit most strongly reflects the characteristics of the scale, and by generating a melody sound based on the melody sound data obtained by adding this most significant bit, the scale requested by the user can be changed. A substantially equal scale can be generated by the piezoelectric buzzer 9. Also,
The melody sound data obtained in this way is D
The analog signal obtained by the conversion by the / A converter 7 includes unnecessary sound frequency components as described later, but since this frequency is often an integral multiple of the required sound frequency, A very high quality sound can be generated as a melody sound. The gain adjustment circuit 103 includes the waveform memory 1
This is to adjust the gain of the scale data sent from 01. By adjusting the gain, the volume of the melody sound can be adjusted, and a melody sound whose volume decreases is generated. Will be possible.

The melody sound data creating circuit 2 creates melody sound data composed of a plurality of scales based on a plurality of scale data generated by the scale data generating circuit 1 as shown in FIG. It comprises a scale data holding register 201, a selector 202, and adders 203 and 204. As will be described later, the adder 203 adds all the bits of the scale data to create melody sound data, and outputs the melody sound data to the D connected to the speaker 8.
/ A converter 6. The adder 204 adds the most significant bit of the scale data to create melody sound data, and sends the melody sound data to the D / A converter 7 connected to the piezoelectric buzzer 9. In particular, in the present embodiment, when the melody sound is generated from the piezoelectric buzzer 9, the most significant bit of the plurality of scale data generated by the scale data generation circuit 1 is added, so that the melody sound including the plurality of scales is added. Creating data. As described above, by adding only the most significant bit having the largest weight of the scale data, it is possible to reduce the number of waveform steps and obtain a sufficient volume.

The above-mentioned scale data holding register 201
Temporarily stores the scale data of the main melody tone transmitted from the gain adjustment circuit 103 and the data of the scales constituting the chord accompanying the scale data in accordance with an instruction from the sequence control circuit 3 described later. The predetermined bits of the held scale data are sent to an adder 203 or 204, which will be described later, via a selector 202 according to an instruction from the sequence control circuit 3. Here, when the held scale data is sent to the adder 203 via the selector 202, all bits (14 bits) of the scale data are sent. On the other hand, when the held scale data is sent to the adder 204 via the selector 202, the most significant bit of the scale data is sent.

The reason why a predetermined bit of the data held in the scale data holding register 201 is selectively given to either the adder 203 or 204 by the selector 202 is as follows. The piezoelectric buzzer 9 has low power consumption, but generates less sound volume than the speaker 8. Although the speaker 8 can output a relatively large volume, the power consumption increases because the diaphragm needs to be driven by a magnet. Therefore, in this embodiment, the user selects the loudspeaker 8 or the piezoelectric buzzer 9 using the numeric keypad 4 or the like according to the respective applications, so that the selector 202 stores the data held in the scale data holding register 201. It is possible to selectively switch between providing a predetermined bit to the speaker 8 via the adder 203 and the D / A converter 6 or providing the predetermined bit to the piezoelectric buzzer 9 via the adder 204 and the D / A converter 7. Make up. Note that the speaker 8 in the present embodiment is also used as a speaker on the receiving side, and includes a magnet, a diaphragm, and a drive amplifier thereof, although not particularly shown. The piezoelectric buzzer 9 will be described later.

The adder 203 is a scale data holding register 2
The melody sound data is created by adding a plurality of all bits of the scale data sent from 01, in this embodiment, 14 bits, and this melody sound data is connected to the speaker 8 connected to the D.
/ A converter 6 The adder 204 adds a plurality of the most significant bits of the scale data sent from the scale data holding register 201 to create melody sound data, and converts the melody sound data to a D / A converter connected to the piezoelectric buzzer 9. Send to 7. Therefore, the number of bits of the melody sound data obtained by the addition by the adder 204 is
03 is smaller than the bit number of the melody sound data obtained by addition. This specific description will be described later.

The sequence control circuit 3 controls the sequence of the scale data generation circuit 1 and the melody sound data creation circuit 2 based on a control procedure previously stored by the user via the numeric keypad 4. Specifically, the sequence control circuit 3 instructs the scale data generation circuit 1 to generate the scale data of the main melody and the scale data forming the chord. Here, when the scale of the main melody note of the melody sound matches one of the scales of the chord,
The scale data generation circuit 1 is controlled so that only the data of the scale of the main melody note among the matched scales is generated as melody sound data. The sequence control circuit 3
Is the number of bits of the scale data held in the scale data holding register 201 included in the melody sound data creation circuit 2, and how many bits are added to the adder 203 or the adder 2.
04 is instructed to the scale data holding register 201. Specifically, when sending to the adder 203, it is instructed to send all bits of the scale data held in the scale data holding register 201, and when sending to the adder 204, the scale data holding register 201 is instructed. Indicates that the most significant bit of the scale data to be retained is sent. Further, the sequence control circuit 3 adds such scale data to the adder 2.
The selector 202 is controlled to select whether to send to the adder 03 or to the adder 204.

The control procedure of the scale data generation circuit 1 and the melody sound data creation circuit 2 performed by the sequence control circuit 3 is stored by the user. In particular, in the present embodiment, when a chord is designated by operating the numeric keypad 4, the sequence control circuit 3 stores a control procedure for generating scale data of the designated chord.

The numeric keypad 4 is usually used for inputting a telephone number or the like of the other party, but in this embodiment, in particular,
By operating the numeric keypad 4 in accordance with a predetermined procedure, the user can create his favorite melody sound. Specifically, when creating the main melody tone that constitutes the melody tone, the user specifies the scale one by one according to a predetermined procedure. On the other hand, when a chord constituting a melody tone is designated, a chord constituting chord or the like is constituted by designating the chord according to a predetermined procedure. By operating the numeric keypad 4 according to a predetermined procedure, it is possible to instruct a change of a melody sound generation destination. That is, a selection is made as to whether a melody sound is generated from the speaker 8 or a melody sound is generated from the piezoelectric buzzer 9, and the selector 202 is switched according to the selection.

The D / A converter 6 converts the digital melody sound data sent from the adder 203 of the melody sound data creation circuit 2 into an analog signal. This analog signal is represented by a step level corresponding to the number of bits of the melody sound data. However, since the number of bits of the melody sound data sent from the adder 203 is large as described above, the level of the melody sound also increases, and It has a smooth waveform. Then, the melody sound data converted into the analog signal is given to the speaker 8, and is generated as a ringtone or a hold tone via the speaker 8. Thus, the user is notified that there is an incoming call. Also, the melody sound data as a digital signal can be output via the sound CODEC 10 and the transmission circuit 11, and can be generated as a hold sound in the receiving speaker of the partner terminal.

The D / A converter 7 converts the melody sound data sent from the adder 204 of the melody sound data creation circuit 2 into an analog signal. This analog signal is represented by a step level corresponding to the number of bits of the melody sound data sent from the adder 204. Here, the possible value of the melody sound data sent from the adder 204 is a pattern obtained by adding one to the number of sounds constituting the melody sound, as will be specifically described later. Therefore, when the melody sound data is converted by the D / A converter 7, the level of the analog signal becomes one obtained by adding 1 to the number of sounds constituting the melody sound, and is converted by the D / A converter 6. It is much smaller than the level of the analog signal obtained. Therefore, a melody sound can be generated from the piezoelectric buzzer 9 at a sufficient volume.

Since the piezoelectric buzzer 9 is directly driven based on the analog signal obtained by the D / A converter 7, noise can be suppressed as compared with the case where the piezoelectric buzzer 9 is driven by a pulse signal. And a melody sound with good sound quality can be generated. That is, since the piezoelectric buzzer 9 is not driven by the pulse signal, the piezoelectric buzzer 9 is not driven.
Can accurately follow the frequencies of a plurality of scales, and can generate a melody sound with good sound quality. by the way,
Since this analog signal is obtained based on adding only the most significant bit of the scale data, the analog signal contains many unnecessary sound frequency components as compared with a signal obtained by adding all bits. Unwanted frequency components can be a source of noise, but this analog signal is obtained based on the addition of the most significant bit with the highest weight. Is often an integral multiple of the required sound frequency. For this reason, there is little discomfort when the user listens as sound. Therefore, the melody sound generating device utilizing such characteristics can generate a sound with extremely high sound quality as a melody sound.

The piezoelectric buzzer 9 generates sound by vibrating the piezoelectric vibrator 92 by applying a voltage. The piezoelectric buzzer 9 specifically includes a piezoelectric vibrator drive circuit 91 and a piezoelectric vibrator 92. The piezoelectric vibrator drive circuit 91 receives an analog signal having a predetermined step level from the D / A converter 7, generates a predetermined voltage according to the analog signal, and supplies the generated voltage to the piezoelectric vibrator 92. Here, an appropriate value is selected as the predetermined voltage so as to vibrate the piezoelectric vibrator 92 with a predetermined value of deflection. Then, the piezoelectric vibrator 92 vibrates at the same frequency as the given predetermined voltage, and generates a predetermined tone color corresponding to the frequency.

Next, the operation of the melody sound generating device according to this embodiment will be described.

First, it is assumed that the sequence control circuit 3
Stores a control procedure for generating a main melody sound and a chord as a melody sound based on a user's operation of the numeric keypad 4 according to a predetermined procedure. Further, the user gives an instruction using the numeric keypad 4 to generate a melody sound from the piezoelectric buzzer 9. Therefore, the selector 202 sets the scale data holding register 20
The output from 1 is switched to be provided to adder 204. Here, the number of notes that make up the chord is 2
It will be described as one. Therefore, the number of sounds constituting the melody sound is three in total, one sound of the main melody sound and two sounds of the chord.

When the user is notified that there is an incoming call or the like by a melody sound, the sequence control circuit 3
Performs an instruction for generating scale data to the scale data generation circuit 1 based on a control procedure stored in advance. That is,
The sequence control circuit 3 instructs the scale data generation circuit 1 to generate the scale data of the main melody and the scale data of the chord. At this time, when the scale of the main melody note matches one of the scales constituting the chord, the sequence control circuit 3 generates only one of the scales in this embodiment. To generate only the scale data of the main melody,
It instructs the scale data generation circuit 1.

Then, the address generator 102 of the scale data generation circuit 1 specifies an address of the waveform memory 101 so that the data of the scale specified by the sequence control circuit 3 is generated in the waveform memory 101. And
When the address is specified, sine wave data of a predetermined frequency is sent from the waveform memory 101 to the gain adjustment circuit 103 as 14-bit scale data. The gain adjustment circuit 103 adjusts the gain of the scale data sent from the waveform memory 101 according to a command from the sequence control circuit 3. Then, the scale data whose gain has been adjusted is sent to the melody sound data creation circuit 2.

The scale data holding register 201 of the melody sound data creating circuit 2 configures the scale data of the 14-bit main melody sound sent from the gain adjusting circuit 103 and the code associated therewith in accordance with the instruction of the sequence control circuit 3. Temporarily retain scale data. Then, the sequence control circuit 3 instructs the scale data holding register 201 to send the most significant bits of the scale data of the three tones composed of the main melody tone and the chord to the adder 204 via the selector 202. Adder 204
Then, these most significant bits are added to create melody sound data. Here, the melody sound data is, for example, 3
If the most significant bits in the scale data of the sound are all “1”, “1” + “1” + “1” = “11”, and the most significant bits in the scale data of the three sounds are all “0”. In this case, “0” + “0” + “0” = “00”. Therefore, the melody sound data obtained by the adder 204 has four patterns of “00”, “01”, “10”, and “11”. That is, the possible value of the melody sound data is obtained by adding 1 to the number (three) of the sounds constituting the melody sound,
There are four patterns. Then, the melody sound data (2 bits) is sent to the D / A converter 7. In this case, the D / A converter 7 only needs to correspond to at least 2 bits.

The D / A converter 7 having obtained the melody sound data as a digital signal converts the melody sound data of 2 bits into an analog signal of 4 levels. Specifically, if the melody sound data is “11” (corresponding to 3 in decimal) as described above, the step level is set to 3, and the melody sound data is “00” as described above.
If (equivalent to 0 in decimal number), the step level is set to 0. In this way, the step level of the analog signal is set to one of the four step levels. That is, when the melody sound data is converted by the D / A converter 7, the number of step levels of the analog signal becomes the number of sounds (3
1) plus one.

The melody sound data converted into an analog signal having a predetermined level, in this embodiment, four levels, is supplied to the piezoelectric buzzer 9. The piezoelectric vibrator drive circuit 91 in the piezoelectric buzzer 9 generates a voltage of a predetermined value based on an analog signal having four levels provided from the D / A converter 7 and supplies the voltage to the piezoelectric vibrator 92. The piezoelectric vibrator 92 vibrates with a predetermined value of deflection at the same frequency as the applied voltage, and generates a predetermined timbre corresponding to the frequency. As a result, a melody sound is generated from the piezoelectric buzzer 9 as a ringtone, and the user can listen to a melody sound composed of a plurality of scales.

When a melody sound is generated from the speaker 8, all bits (14 bits) of the scale data of a plurality of sounds stored in the scale data holding register 201 are transmitted by the selector 202 through the selector 202 by the number of sounds. This is provided to the adder 203. The adder 203 adds these scale data to create melody sound data. The melody sound data is sent to the D / A converter 6, where it is converted into an extremely smooth analog signal having multiple stages. Then, this analog signal is given to the speaker 8 and is generated from the speaker 8 as a ringtone.

Therefore, the melody sound generating apparatus according to the present embodiment having such a configuration has the following advantages.

A plurality of scales composed of the main melody and chords;
In the present embodiment, a sound composed of three scales can be generated as a melody sound from the piezoelectric buzzer 9 with low power consumption. As a result, a melody sound composed of a plurality of musical scales that we usually hear as music can be heard via the piezoelectric buzzer 9 as a ringtone or the like.

Further, based on the pulse signal, the piezoelectric buzzer 9
Since the piezoelectric buzzer 9 is driven based on an analog signal instead of driving the piezoelectric buzzer, the piezoelectric buzzer 9 can accurately follow the frequencies of a plurality of musical scales. Therefore, noise can be suppressed, and a melody sound with good sound quality can be generated. Further, the analog signal is a waveform having four levels,
Even when compared with the step level at which the speaker 8 is driven, a sufficient volume can be obtained because the step level is not large. Also, an analog signal is obtained based on the addition of the most significant bit having the highest weight, and a melody sound is generated based on the analog signal. Can be done. In addition, the frequency component of the unnecessary sound included in the melody sound is often an integral multiple of the frequency of the required sound, so that the user can generate a sound with extremely high sound quality as a melody sound.

Further, since the chord can be executed by designating the chord, the user does not need to specify the scales constituting the chord one by one, and the chord data of the chord can be easily programmed. Can reduce the work of creating a melody.

In general, when two identical scale data are added, if the phases of the frequencies of the sine waves constituting the same scale data coincide with each other, the sound volume is doubled. If the phase of the frequency of the sine wave constituting the scale data is shifted by 180 degrees, the volume will be zero. Therefore, in this embodiment, when the scale of the main melody note matches one of the scales constituting the chord, the sequence control circuit 3 generates only data of the scale of the main melody note among the matched scales. To the scale data generation circuit 1 so as to perform the operation. As a result, it is possible to avoid the irrationality that an unnatural sound is generated when the sound volume is doubled or the sound volume becomes zero.

The melody sound generator according to the present invention is not limited to the above-described embodiment, but may be implemented in the following manner.

In the above embodiment, the melody sound data is created by adding the most significant bits of the three sounds that make up the melody sound, and the melody sound data is stored in the D / A
Although it is sent to the converter 7, the present invention is not limited to this. For example, the melody sound data is created by adding the upper two bits of the scale data of the three sounds constituting the melody sound. It may be sent to the D / A converter 7. If the upper two bits of the scale data of the three tones constituting the melody sound are all “11”, the data obtained by the adder 204 is “11” + “11” + “1”.
Since "1" = "1001" (corresponding to 9 in decimal), the D / A converter 7 may set the step level to 9, and if the upper two bits are all "00", the adder The data obtained in 204 is “00” + “00” + “0”
Since “0” = “0000” (corresponding to 0 in decimal number), the D / A converter 7 may set the step level to 0. That is, in this case, analog signals may be assigned at 10 levels. In this case, the D / A converter 7
Uses one that can convert at least 4-bit data into an analog signal. According to this, since the number of step levels is 10, even if the volume is lower than in the case of step level 4 shown in the above embodiment, the sound quality of the piezoelectric buzzer 9 is improved. Therefore, how many bits are set to the upper predetermined bits of the scale data added by the D / A converter 7 may be determined by comparing the sound volume and sound quality required of the melody sound generator.

In the above embodiment, the adder 204
The melody sound data obtained by the addition is converted into an analog signal by the D / A converter 7 and sent to the piezoelectric buzzer 9. The signal may be converted into an analog signal by the A converter 6 and sent to the piezoelectric buzzer 9. At this time, a selector may be provided on the output side of the D / A converter 6 to select whether to output an analog signal to the speaker 8 or the piezoelectric buzzer 9. As described above, the D / A converter 6 can convert the melody sound data obtained by adding all the bits of the scale data to an analog signal, so that the melody added by the adder 204 is obtained. Sound data can be converted to an analog signal. As a result, since the D / A converter 7 can be omitted, the configuration of the melody sound generation circuit can be simplified, and the manufacturing cost can be reduced.

In the above embodiment, the scale data of the main melody and the scale data of the chord are generated in the scale data generation circuit 1 and the melody sound data generation circuit 2
Is to create melody sound data by adding these plurality of scale data. For example, rhythm sound data such as a rhythm instrument such as a cymbal can be generated as rhythm sound data. The melody sound data may be generated by a circuit, and the melody sound data generation circuit 2 may add the rhythm sound data to generate melody sound data. According to this, the rhythm sound can be generated as one of the melody sounds.

Further, in the above embodiment, the waveform memory 101 stores data of one cycle of a single sine waveform as a memory, but is not limited to data of one cycle. It is sufficient that sufficient data is stored for the scale data generation circuit 1 to generate data for one cycle. For example, the memory stored in the waveform memory 101 is set to a quarter cycle of a single sine waveform, and the address generator 102 controls the reading order and polarity of the memory, so that the scale data generation circuit 1 Data for one cycle may be generated.

In the above embodiment, the gain adjustment circuit 103 is one of the components of the musical scale data generation circuit 1, but this gain adjustment circuit 103 is not an essential component. The gain adjustment circuit 103 is for adjusting the gain. When the gain adjustment circuit 103 is not provided, the gain is not adjusted, but it is possible to generate a melody sound composed of a main melody sound and a chord.

[0047]

As described above in detail, according to the present invention, a melody sound composed of a plurality of scales can be generated from a low-power-consumption piezoelectric buzzer as a ringing tone or a holding tone. As a result, a melody sound composed of a plurality of musical scales that we usually hear as music can be heard as a ringtone or the like via the piezoelectric buzzer.

Since the piezoelectric buzzer is driven based on an analog signal instead of driving the piezoelectric buzzer based on a pulse signal, the piezoelectric buzzer can accurately follow the frequencies of a plurality of musical scales. As a result, noise can be suppressed, and a melody sound with good sound quality can be generated. Further, since a melody sound is generated by a stepwise analog waveform obtained based on adding only upper predetermined bits of a plurality of scale data, a sufficient volume can be obtained. The melody sound is generated by the analog signal obtained based on the addition of the high-order predetermined bits having a large weight, particularly the most significant bit, so that a sound with high auditory quality can be generated as the melody sound.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a melody sound generating device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a scale data generation circuit 1 constituting the melody sound generation device.

FIG. 3 is a configuration diagram of a melody sound data creation circuit 2 configuring the melody sound generation device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 scale data generation circuit 2 melody sound data creation circuit 3 sequence control circuit 4 numeric keypad 7 D / A converter 9 piezoelectric buzzer 91 piezoelectric vibrator drive circuit 92 piezoelectric vibrator 201 scale data holding register 204 adder

Claims (2)

[Claims] 1. A melody sound generating device for generating a melody sound having a predetermined scale, a scale data generating means for generating scale data including predetermined bits based on a predetermined scale, and a scale data generating means for generating the scale data including the predetermined bits. Melody sound data creating means for creating melody sound data composed of a plurality of scales by adding upper predetermined bits of a plurality of scale data, and a digital converter for converting digital data created by the melody sound data creating means into an analog signal A melody sound generating device comprising: analog conversion means; and piezoelectric buzzer means for generating a melody sound by vibrating a piezoelectric vibrator based on an output of the digital / analog conversion means. 2. The melody sound data according to claim 1, wherein said melody sound data generation means generates melody sound data by adding a most significant bit of scale data generated by said scale data generation means. Sound generator.