JPS62134692A - 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] [Field of Industrial Application] The present invention samples an acoustic analog signal emitted from an external sound source, digitizes it with an A/D converter, stores it in a memory temporarily, and converts the pitch by digital calculation. The present invention relates to a device (hereinafter referred to as a musical tone generating device with a sampling tool) that generates musical tones by adding musical scales.

In particular, it relates to control of sampling time and sampling clock in an A/D converter.

[Summary of the invention]

Incorporates external acoustic analog signals as human power.

After digitizing with an A/D converter to obtain musical waveform data and temporarily storing it in memory.

In a device that performs pitch conversion using digital υIW and synthesizes and generates musical tones, the sampling time and By making the sampling frequency adjustable, the sampling time can be freely expanded or contracted according to the time length of the external acoustic analog signal without changing the storage capacity of the memory.

[Conventional technology]

Conventionally, external acoustic analog signals are taken in as input, digitized with an A/D converter to create basic musical waveform data, temporarily stored in memory, pitch converted using digital calculations, and musical tones synthesized. let A so-called musical sound generator with a sampling tool has been known. For example, it is an electronic keyboard instrument that incorporates the sounds of birds and adds a scale to it.

Now, a large capacity memory (64 bytes, for example) is used for temporarily storing the digitized basic musical waveform data. The A/D converter operates with 32 KIIZ sampling clock pulses. That is, numerical values are sampled from analog signal data approximately 32,000 times per second to obtain digital data. Sampling 2
If executed for seconds, a total of approximately 64,000 (11) pieces of digital data will be obtained, filling the entire memory capacity. Therefore, it is possible to collect sounds from an external sound source that are continuous for a maximum of 2 seconds.
Using a 2KIIZ sampling clock, it is theoretically possible to digitize a maximum of 16KIIZ audio analog signals. Human audible frequency range increases by 1 from 2011Z to 20
Because it is between 2.

Can cover the entire area.

[Problem that the invention seeks to solve]

However, the conventional technology has the following problems. In other words, among the sounds of the natural world that we try to collect, there are many that last more than two seconds, such as the sound of five bells and the chirping of birds. As a result, there were natural sounds that could not be collected using conventional techniques, and the scope of their use was limited.

[Means for solving problems]

The present invention aims to solve the above problems. For this purpose, the following configuration means (4) are adopted:
In an A/D converter, basic musical waveform data is obtained by digitizing it with an A/D converter, which is temporarily stored in a large-capacity memory, and then digitally calculated to give a desired pitch to synthesize the musical tone and reproduce it. The sampling time and sampling frequency are fIli!, provided that the product of the conversion sampling time of the analog input signal and the conversion sampling clock frequency is commensurate with the storage capacity of the memory. By making it possible to adjust the sampling time, the sampling time can be selected according to the duration of the external acoustic analog signal without the need for adding a memory element.

〔Example〕

Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a circuit block diagram of a musical tone generator with a sampling tool. 1 is an audio analog signal input circuit.

A circuit that accepts and captures analog signals obtained by converting sounds generated in the natural world into electrical signals using a microphone, and analog signals supplied from other audio devices (e.g., radios, televisions, tape recorders, record players, etc.). be. An example of an acoustic analog electrical signal is shown in FIG. It has a unique duration, a unique envelope 2 and a unique frequency 3. The input acoustic analog signal (hereinafter simply referred to as analog data) is amplified by the input amplifier circuit 4, and then goes to the ^/D converter 5 where it is converted into digital data. The A/D converter itself is well known, and a detailed explanation will be omitted, but it is an element that samples analog data, launches or samples it at predetermined time intervals in synchronization with clock pulses, and converts it into a set of discrete point data. . The obtained digital data is temporarily stored in the digital storage circuit 6. By the way, the memory capacity of the digital storage circuit 6 is finite and is determined by the cost and processing power of the CPU. In the case of this device, the memory capacity is 64 bytes.
(In other words, it is possible to store digital data of approximately 64,000 yen), but the present invention is not limited to this.

Now, based on the above explanation, here are five characteristic parts of the present invention. The sampling clock selection circuit 7 will be explained. The sampling clock selection circuit 7 manually selects one of the four sampling clock pulses having different periods shown in Table 1 and supplies it to the Δ/D converter 5.

Table 1 If you select the 32KIIZ sampling clock now.

32,000 analog data clutches are performed per second, giving 32,0007 digital data i. Then, the sampling is maintained for 2 seconds and the total of 2 is 64,
000 pieces of digital data are obtained, which corresponds to the memory capacity of the digital storage circuit 6. In this case, theoretically
The upper limit of the frequency band of acoustic analog waveforms that can be converted into D is 1.
It will be 6KIIZ. Since the audible band upper limit is 20KH2,
That's quite enough. Next, if you select a sampling clock pulse of 16KH2, 16KH2 per second. .

Since latching is performed 00 times, a sampling duration of 4 seconds is obtained, and the upper limit of the A/D convertible band is reduced to 8 KIIZ. Also, if you select the 8 KIIZ sampling clock pulse, the sampling time will be as long as 8 seconds, and the A/
The upper limit of the D conversion band is 4XIIZ. 4 more
If you select IIZ's sampling clock pulse.

The sampling time is 16 seconds, and the upper limit of the A/D convertible band is 2 KIIZ. Below, the product of the sampling clock pulse frequency and the sampling time is set to match the memory capacity.

Now, the selection criteria for the sampling pattern will be explained with reference to FIG. If the duration of the acoustic waveform (for example, the sound of raindrops) is less than 2 seconds, manually select the sampling clock of 32KIIZ.

If the sound source is a bell or the like, and the sustain time is expected to be 8 seconds or more, select the 4 KIIZ sampling clock. In this way, the sampling clock frequency is appropriately selected according to the vibration time of the sound source. Note that if the sampling clock frequency is made smaller and the sampling time is made longer, the upper limit of the A/D convertible band will be lowered, resulting in the problem that high-frequency trebles will be cut. However, in general, when it comes to sounds in the natural world, high-pitched sounds attenuate quickly;
Since the bass tends to have a lingering sound, there is no problem in practical terms.

Now, let's go back to Figure 1. Reference numeral 8 denotes a fast Fourier transform circuit which successively extracts predetermined periods (hereinafter referred to as stages) of the stored digital tone waveform basic data in time series and performs spectral decomposition. Then, a predetermined number of high-intensity harmonics are selected and stored in the primary stage memory 9. IO is a pinch conversion circuit that converts the frequency of the high frequency group and gives a desired pinch, that is, a musical scale.

Reference numeral 11 denotes an overtone addition circuit which adds and synthesizes high frequency groups to obtain a musical sound waveform. 12 is a D/^ converter, which converts the digital musical sound waveform into an analog signal. After this is amplified by the output amplification circuit 13.

The electroacoustic transducer 14 produces musical sounds.

FIG. 3 shows a specific example of the sampling clock selection circuit 7. 15 is a crystal oscillator that oscillates a clock pulse of 32KllZ, and its output is connected to a multistage frequency divider circuit and a manual switch 17.
connected to one of the 16 is a multi-stage frequency divider circuit in which flip-flops are connected in series to perform 1/2 frequency division, 16 KIZ from each stage, +12 to 8 and 4 KIIZ
Outputs the clock pulse.

17 is a manual switch to select one of the 54 clock pulses. 18 is a timer which starts timing in conjunction with the manual switch 17.

A/D converter 5 via OR gate 19 for a predetermined time.
the selected clock pulses.

〔Effect of the invention〕

According to the present invention, in a musical tone generator with a sampling tool, the sampling time and the sampling frequency can be adjusted so that the product of the sampling time and the sampling clock frequency in the A/D converter corresponds to the memory capacity. The effect is that the sampling time can be freely expanded or contracted according to the duration of external acoustic vibration without adding storage capacity.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram of a musical tone generator with a sampling tool, FIG. 2 is a waveform diagram of a musical analog electrical signal, and FIG. 3 is a sampling clock selection circuit diagram. ■...Sound analog signal input circuit 5...To/D converter 6...Digital storage circuit 7...Sampling clock selection circuit 8...Fast Fourier transform circuit 10...Pitch conversion circuit 11...Overtone addition circuit 12... Electro-acoustic converter bag 〇 sample lure ゛ tool with chestnut soil device block diagram No.
l figure

Claims (1)

[Claims] An acoustic analog signal emitted from an external sound source is input into an input circuit, converted into digital musical waveform data by an A/D converter, and once stored in a digital storage circuit, a musical tone is synthesized by adding a scale through arithmetic processing and generated. In a musical tone generating device that outputs a sampling clock of a predetermined frequency to the A/D converter, a sampling clock of a predetermined frequency is output to the A/D converter within a desired sampling time such that the product of the sampling time in the A/D converter and the sampling clock frequency corresponds to the capacity of the digital storage circuit.
A musical tone generating device characterized by being provided with a sampling clock selection circuit for supplying to a converter.