JPS61196297A - Musical sound generator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. (Industrial Application Field) The present invention relates to a musical tone generation circuit using digital technology, and particularly relates to processing of partial tone level data and envelope circuits constituting musical tones.

B. (Summary of the Invention) In the present invention, a musical tone is composed of a plurality of partials, and by specifying the pitch of each partial and setting the level of each partial, the timbre and level of the musical tone can be specified. It has a configuration in which musical tones are set, and has two sets of registers for specifying the level of each partial tone, and when data enters the two registers, the weighting is changed linearly, and one level specifying register is all zero. Musical tones are created by increasing and decreasing time-logarithmically.

C. (Prior Art) As a configuration for partial tone synthesis musical tone generation, there is a method in which an envelope counter tVL is used for each partial tone, the waveform of each partial tone is multiplied by the envelope, and the results are completely added to produce a musical tone.

D. (Problem to be solved by the invention) Providing an envelope counter for each partial tone requires a large circuit scale.

Since the scale of the multiplier circuit for each partial is large, it is possible to change the musical tone smoothly and linearly using two sets of partial level data by using a method in which the partial level is scaled logarithmically and the envelope counter data is also added as logarithmic data. The present invention solves these problems.

Means for solving problems E and C] 1. In the present invention, two sets of level registers f for each partial sound constituting a musical tone are provided; 2. . One set of the most significant bits has an envelope counter that performs data inversion control, and (5) has a switching means that directly outputs envelope count data or outputs virtual data that has been converted from a real number to a logarithm, and (4.1) set. All partial tone level registers are zer.

5. The switching circuit output is data inversion controlled by the counter inversion control bit, & has two sets of adders, one of which has one set. 1. The other adder adds the partial level register output of the other set and the data inversion control output that is controlled in opposite phase to that of the other set, and The adder output is added to the logarithmic waveform data, then converted into a real number, added to 90, and converted into the resulting digital signal 'i+)/A to obtain an analog musical tone.

F. (Function) By taking the above 491 K 'e, the envelope counter has the role of smoothly exchanging musical tones consisting of two sets of multiple partial levels, and the role of causing one set of partial levels to rise or fall in a logarithmic curve. The pitch and level of each partial are determined by an external control circuit.

By instructing the envelope counter and step speed, it is possible to generate musical tones with a high degree of freedom.

G. (Example) FIG. 1 is an overall block diagram showing the main parts of the present invention.

In this example, it is assumed that there are 8 musical tones generated and one musical tone consists of 8 partials, and if the system clock is \, then 64X,
One partial tone is controlled for each tone channel, and 8\ is a clock for each tone channel.

If \=217Hz, 8J=250KHz64'Q
, = 31.25 KHz.

The basic pitch partial register 1 that constitutes a musical tone is composed of multiple rows of 8-stage shift registers, and the shift clock is 8.
It is \. Inter-partial division between adjacent partials of a group of partials constituting a musical tone The pitch register 2 is composed of a plurality of rows of eight-stage shift registers, and the shift clock is \.

The addend converter 3 outputs addend data of the pitch counter 4 for each \ from the data of the basic pitch register 1 and the intertone division register 2.

The pitch counter 4 is composed of multiple rows of 64-stage shift registers and an adder, and creates pitch data of 64 partials.

A logarithmic scale waveform memory 5 is addressed by a pitch counter 4 and outputs 64 partial waveforms in a time-divisional manner.

The A partial level register 6 is composed of multiple columns of 8-stage shift registers, and is shifted by \.

The Bi partial tone register 7 has the same structure as the A partial tone register register, and the speed register 8 is a plurality of 8-stage shift registers that are shifted at a rate of 8\.

The envelope counter 9 is composed of a plurality of columns of 8-stage shift registers and an adder, and constitutes eight envelope counters whose progress is controlled by the output of the speed register 8 in a time-division manner.

The inversion control bit 10 consists of one column of 8-stage shift register and an adder, and the MAX-+ze of the envelope counter 9.
The bit is inverted by a carry at ro.

The output of the real number-to-logarithm conversion ROM 11 is converted into a real number and logarithmic data, which resembles linear data, is obtained.

The converter 12 switches between envelope counter direct data and real number-to-log conversion ROM output data.

When the human or Bl'lS diacritic level register data 6 or 7 are all zero, the real number conversion ROM output is switched and outputted.
, B When data exists in both partial tone level registers, the envelope counter direct delta is output by the switch.

In the exclusive OR gate group 10-1, when the inversion control bit 10 is L, the adder output is directly added to the adder 13, and when it is H, the inverted data is added.

When the exclusive OR gate group 10-2 has the inversion control bit 10 at L, the inverted data of the switch output is sent to the adder 1.
4, and the H-time switch output is added.

The adder 13 outputs the A partial level data and exclusive
v or game) #10-1 output is input, adder 15
Enter.

The adder 14 outputs 8 partial tone level data and exclusive
The eor gate group 10-2 output is input and input to the adder 16. The logarithm-real conversion ROM 17 obtains the multiplication output of the A partial level data, envelope counter data, and waveform, and the logarithm-real conversion ROM 18 obtains the multiplication output of the 8 partial tone level data, envelope counter data, and the waveform.

The logarithm-to-real conversion ROMs 17 and 18 perform addition in an adder 19, and the output of the D/A converter 20 obtains eight tone analog signals.

The external control circuit is a data bus and a control bus.

Data is specified to each register group via the address bus. ``At the time of envelope counter data, the output of the multi-input NAND gate 31 becomes L level (DRQ) and requests new data from the outside.

Next, FIG. 2 shows a clock time chart.

CHs are numbered from \ to 63 for each clock, and CH numbers N to 7 are 8 partial tone control times of voice number 1, and 8 clocks exist every 8 times.

FIG. 3 shows an image of the musical tone obtained when inputting various data from an external control circuit.

(1) Shows the movement of the envelope counter.

(2) shows the movement i of the inversion control bit.

(3) shows the musical tone output consisting of the A partial.

(4) is B (5) shows the musical sound output as a result of synthesizing the A and B partials.

T is the time from when the envelope counter becomes MAX and requests data from the outside until nine deltas are input.

For humans, data exists only in the A partial register and the part B rises on a logarithmic curve.The part CFi changes linearly from the A partial to the B partial.The part CFi changes linearly from the B partial to the A partial. Only the Dti AN partial register has data and is attenuated according to a logarithmic curve.

FIG. 4 shows an example in which envelope counter data is used as data for directly switching from the A partial to the B partial.

As shown by the broken line, the D/A conversion output has a problem in that the amplitude is small at the center.

H. (Effects of the Invention) As described above, according to the present invention, when generating musical tones by partial tone synthesis, it is possible to externally specify the pitch of a partial tone, specify the step speed of an envelope counter, and specify two sets of partial tone levels. By doing so, a musical tone generation circuit having a simple structure with a high degree of freedom is constructed.

[Brief explanation of drawings]

Figure 1 is a circuit block diagram of Honjimei. The g2 diagram is a timing chart. No. 31 ¥1 is a side view of the output musical sound waveform. Figure 4 is an example of a defective waveform change showing the effectiveness of the present invention. that's all Applicant: Seiko Electronics Industries Co., Ltd. Representative Patent Attorney Mogami Output musical tone 311 type Figure 3 Defect waveform change showing the effectiveness of the present invention Fig. 1

Claims (1)

[Claims] (1) It has multiple channels and generates multiple musical tones. Each musical tone is composed of a small number of partials, and each channel is connected to a musical tone generator with a time division multiplex configuration that corresponds to each partial. In this case, a. It has two sets of level registers for partial tones constituting a musical tone, b. The upper 1 bit of the envelope counter means is an inversion control bit for count data output, and c. The switching circuit means directly outputs the envelope counter. and has a function of switching the output obtained by converting the envelope count data into a real number and logarithm, d. Performs switching circuit control to obtain a logarithmically converted output when all of the set of partial tone registers are zero, and e. The switching circuit output is: The data inversion is controlled by the counter inversion control bit f. It has two sets of adders, one of which adds the partial tone level register output of one set and the data inversion control output, g. The other adder adds the output of the other set of Add the partial tone level register output and the data inversion control output with the opposite phase to one, and add the output of each adder with the logarithmic waveform data.
A musical tone generator configured to perform addition after real number conversion, and perform D/A conversion of the obtained digital musical tone data for acoustic conversion.