JPH06230784A - Apparatus for generation of addresses of electronic musical instrument - Google Patents

Abstract

PURPOSE: To reduce the capacity of a PCM data memory by varying intervals at which PCM data of one octave are read and generating many octave sounds. CONSTITUTION: This device consists of a control signal generation part 100 which outputs a read/write signal, with a frequency clock outputted by a frequency generation part, a RAM 101 which outputs or stores address data of the frequency clock with the output read/write signal, a decoder 102 which selects address data, increased with an external octave select signal, and an adder 103 which adds the selected address data and the access data stored in the RAM 10 and accesses the PCM data with the obtained addition data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic musical instrument. More specifically, the interval for reading one octave of PCM data is varied to generate a large number of octave sounds, thereby reducing the size of the PCM data memory. The present invention relates to a possible address generator.

[0002]

2. Description of the Related Art Generally, in a sound generator of an electronic musical instrument, a frequency generator 10 for generating a frequency clock FCLK for reading PCM data, as shown in FIG.
Frequency clock FCL output from the frequency generator 10
An address generation unit 20 that generates address data ADDR by K, and a PCM data memory unit 30 that stores PCM data corresponding to each sound and outputs the PCM data stored in the address data ADDR of the address generation unit 20.
A data processing section 40 for processing PCM data in the PCM data memory section 30, a data output section 50 for outputting sound data processed by the data processing section 40, and sound data output from the data output section 50 Was converted into an analog signal and a sound signal was output.

Further, in the conventional address generator 20, as shown in FIG. 4, a control signal output by controlling the read / write signal READ / WRITE by the frequency clock FCLK output from the frequency generator 10. The generation unit 21, the RAM 22 which is a memory for outputting or storing the address data of the frequency clock FCLK according to the read / write signals READ / WRITE of the control signal generation unit 21, and the current address data stored in the RAM 22 Increase the PCM data memory unit 3
And an adder 23 for outputting 0.

The operation of the general electronic musical instrument thus constructed and its address generator will be described below. As shown in FIGS. 3 to 5, when the frequency clock FCLK is output from the frequency generator 10, the frequency clock FCLK is output.
Causes the control signal generator 21 of the address generator 20 to output a read / write (READ / WRITE) signal (see FIG. 5A). In this case, as shown in FIG. Read from the control signal generator 21 (REA
D) When the signal is output, the current address data stored in the RAM 22 is read and the adder 23 outputs 1
The increased address data ADDR is output to the PCM data memory unit 30.

As shown in FIG. 5C, when the write signal WRITE is output from the control signal generator 21, the address data ADDR incremented by 1 by the adder 23 is stored in the RAM 22. . Next, the PC generated by the frequency clock FCLK output from the frequency generator 10 and stored in the address data ADDR
The M data is output from the PCM data memory unit 30, the output PCM data is accessed by the frequency clock FCLK, and the accessed PCM data is input to the data processing unit 40 and then output from the data output unit 5. The sound data is applied to the D / A converter 60, converted into an analog signal, and output as a sound signal.

At this time, the frequency clock FCLK output from the frequency generator is about 30 to 60 KHz,
It cannot be changed except for one octave. That is, as shown in FIG. 6, if the frequency clock of the "si" sound of octave 1 is about 63.2 KHz, the frequency clock of the "si" sound of octave 2 is about 63.2 × 2 = 126. Since the frequency clock becomes 4 KHz and the frequency clock cannot be practically realized, normally, PCM data corresponding to a sound is generated for each octave.

[0007]

However, in such a conventional address generator of an electronic musical instrument, a PC of octave 2 which is twice the sampling frequency of octave 1 is used.
When the M data is stored and the sound of the octave 2 is generated, the PCM data of the octave 2 is accessed, so that the PCM data of the octaves 2, 3, 4 ... Is required, and therefore, the memory of the PCM data memory unit. The disadvantage is that the capacity becomes large.

An object of the present invention is to provide an address generating device for an electronic musical instrument which can reduce the size of the PCM data memory unit by varying the interval for reading PCM data of one octave so that a large number of octave sounds can be generated. Is what you are trying to do.

[0009]

The object of the present invention is to provide a control signal generating section for outputting a read / write signal according to a frequency clock output from the frequency generating section, and to output from the control signal generating section. A RAM for outputting or storing the address data of the frequency clock by a read / write signal, a decoder for selecting the address data increased by an octave selection signal input from the outside, and an address data selected by the decoder and the RAM This is achieved by configuring an address generating device of an electronic musical instrument by adding the stored address data and adding the PCM data with the added address data.

[0010]

[Operation] When a read signal is output from the control signal generator,
The increased address data is stored in the RAM, and when the write signal is output, the stored address data in the RAM is applied to the adder. On the other hand, the address data that is incremented by one octave by the external octave selection signal is output from the decoder, and the incremented address data and the RAM are output.
Is added by the adder and applied to the PCM data memory unit.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. As shown in FIG. 1, in the address generator of the electronic musical instrument according to the present invention, the control signal generator 100 that outputs the read / write signals READ / WRITE according to the frequency clock FCLK output from the frequency generator.
And the output read / write signal READ / WRI
RAM 101 for outputting or storing the address data of the frequency clock FCLK by TE, a decoder 102 for selecting the address data increased by the input octave selection signal, and storing the address data selected by the decoder 102 and the RAM 101. And the adder 103 for accessing the PCM data with the added address data.

The operation of the address generating device for an electronic musical instrument according to the present invention having the above-described structure will be described below. As shown in FIG. 1, the frequency generator outputs the frequency clock FCL.
When K is input, the read / write control signal READ / WRITE is output from the control signal generator 100 in response to the frequency clock FCLK. In this case, when the read signal READ is output from the control signal generator 100, the PCM
To access the data, the address data obtained by adding 1 to the current address data is stored in the RAM 101. If the control signal generator 100 outputs a write signal WR
When ITE outputs, the address data stored in the RAM 101 is applied to the adder 103.

On the other hand, address data which is incremented by one octave by an octave selection signal input from the outside is output from the decoder 102, and the address data increased by the decoder 102 and the address data supplied from the RAM 101 are added by an adder. It is applied to 103 and added, and the added address data ADDR is applied to the PCM data memory unit (see FIG. 3). That is, when the input octave selection signal is "0", the decoder 1
The output signal Y0 of 02 becomes "1", the address data becomes "1", the address data is added to the address data of the RAM 101, and the address data ADDR sequentially incremented by "1" is output. When the octave selection signal is "1", the output signal Y1 of the decoder 102 becomes "1" and the address data becomes "2".
The address data is added to the address data in the RAM 101 by the adder 103, and the added address data ADDR is incremented by "2".

The input octave selection signal is "2".
Then, the output signal Y2 of the decoder 102 becomes "2", the address data becomes "4", the address data is added to the address data of the RAM 101 by the adder 103, and the added address data ADDR is "4" is incremented by one. Then, as shown in FIG.
The address data of the PCM data for changing the octave by 2 octaves is increased by 4 times, and a large number of octave sounds are processed by the data processing unit 40 by one PCM data stored in the PCM data memory unit 30 shown in FIG. After that, the data output unit 50 outputs the sound data, and the D / A conversion unit 60 converts the sound data to an analog signal and outputs the sound signal.

[0015]

As described above, in the address generating device for an electronic musical instrument according to the present invention, P of one octave is used.
Since it is possible to generate a large number of octave sounds by changing the intervals at which CM data is read and to reduce the size of the PCM data memory section, there is an effect that it is extremely suitable for making an electronic musical instrument into a digital IC.

[Brief description of drawings]

FIG. 1 is a block diagram showing an address generator of an electronic musical instrument according to the present invention.

FIG. 2 P sampled according to the pitch according to the present invention
It is a CM data display figure.

FIG. 3 is a block diagram of a sound generator of a general electronic musical instrument.

FIG. 4 is a block diagram showing an address generator of a conventional electronic musical instrument.

FIG. 5 is a read / write signal waveform diagram (A, B, C) of the conventional frequency clock of the frequency generator and the control signal generator.
Is.

FIG. 6 is a diagram showing a PCM data sampled by a conventional pitch.

[Explanation of symbols]

 100 ... Control signal generator 101 ... RAM 102 ... Decoder 103 ... Adder

Claims (1)

[Claims] 1. A variable octave address generator for an electronic musical instrument, comprising: a control signal generator for outputting a read / write signal in response to a frequency clock output from the frequency generator; and a control signal generator for outputting the read / write signal. A memory (RAM) that outputs or stores the address data of the frequency clock according to a read / write signal, a decoder that selects address data increased based on an octave selection signal input from the outside, and address data selected by the decoder And an address adder for adding the address data stored in the memory and accessing the PCM data by the added address data.