JPS6068386A - Envelope controller - 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] [Technical field of invention] The present invention relates to an envelope control device.

[Prior art]

2. Description of the Related Art Conventionally, as an envelope control device for an electronic musical instrument or the like, one is known that obtains an envelope waveform that approximates an exponential function waveform by switching the frequency of an input clock of a counter for each state of the envelope.

[Problems with conventional technology]

However, in the above methods, the envelope data value is often switched at the peak or valley of the musical sound waveform.
When the envelope data value is changed in the middle of a peak or valley of a musical sound waveform, the amplitude of the waveform suddenly changes, causing distortion of the waveform and causing noise.

[Purpose of the invention]

The present invention was made against the background of the above-mentioned circumstances, and
Its purpose is to switch envelope data values.
An object of the present invention is to provide an envelope control device that does not distort a waveform and generates less noise.

[Key points of the invention]

In order to achieve the above object, the main point of the present invention is to prevent the waveform from being distorted by switching the envelope data value at the zero point where the amplitude of the waveform becomes zero level.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a frequency information generating section to which the control section 2 detects the depression of keys on a keyboard (not shown) arranged in the order of musical scales and receives the key depression data from the control section 2. The frequency information generating section 1 provides frequency information to the scale clock generating section 3 based on the key press data from the control section 2. The scale clock generator 3 supplies execute signals EX and C, which are signals corresponding to the scale frequency, to the C terminal of the half adder 5 in the address counter 4.

Here, the structure of the address counter 4 will be explained. In addition to the half adder 5 described above, the address counter 4 includes an AND gate group AGI and a latch 6. The half adder 5 has an input terminal A that receives the output of a latch 6 formed by cascading 8 stages of 7-bit shift registers, for example in the case of an 8-note polyphonic time-division processing instrument. -Excue taken into A6 and input to the above CIN terminal) i-EX
O performs addition in increments of "+1", and the resulting data is output to terminal S. -86 output.

In addition, the latch 6 takes in and latches the output of the half adder 5 via an AND gate group AGI consisting of seven AND gates at the time of output of the clock pulse φ, and the AND gate group AGI receives the reset signal R from the control section 2. Opening/closing is controlled.

Therefore, the address counter 4 is configured to increment the 7-bit address data, which is the output of the latch 6, by "1" each time the execute signal EXO is applied.

Address data, which is the output of the latch 6 of the address counter 4, is provided to a waveform ROM (read only memory) section 7 and a waveform zero point detection section 8, respectively. The waveform ROM section 7 sequentially outputs waveform data representing musical tone waveforms to the multiplication section 9 based on the supplied address data.

Further, the waveform zero point detecting section 8 is made up of an anti-game) 10 and an OR gate 11. The AND gate 10 outputs the lower 6 of the 7-bit address data output from the latch 6.
The output of the bit is ANDed with the execute signal EXQ from the control section 2, and the address current input is
lllllll (63)” and rllllllll (127)
J, that is, at the zero point of the half cycle and the zero point of the first cycle of the tone waveform, "1" is output as a zero point signal OGA, which will be described later, at the timing of outputting the execute signal EXO. Further, the OR gate 11 outputs the output of the AND gate 10 and the preset signal PR from the control section 2.
It is logically ORed with.

On the other hand, the control section 2 sends predetermined data to the engine according to the on/off state of the operating keys of the keyboard (not shown).
The signal is applied to the envelope clock generator 12 in accordance with the change in the state g. The envelope clock generator 12 generates an envelope p-button lock signal fEN based on the data from the controller 2.
Apply V-OK to the C terminal of the half adder 14 in the envelope counter 13.

Here, the configuration of the envelope counter 13 will be explained. In addition to the half adder 14 described above, the envelope counter 13 includes an AND gate group AG2, a latch 15, and an inverter group 16. The half adder 14 receives the output of the latch 15 of eight stages of 7-bit shift registers at the input terminal A.

-A, and is added in increments of "+1" by the envelope clock signal FiNV-OK input to the CIN terminal, and the resulting data is output from the output terminal So -8°. Furthermore, the latch 15 takes in and latches the output of the half adder 14 through an AND gate group AG2 made up of seven AND gates at the time of output of the clock pulse φ, and the AND gate group AG2 receives the reset signal R from the control section 2. Opening/closing is controlled. Furthermore, the inverter group 16 consists of seven inverters,
Data obtained by inverting the output of the latch 15 is applied as envelope data to a latch 17 consisting of eight stages of 7-bit shift registers via a game TGI.

Therefore, the envelope counter 13 latches the latch 15 every time the envelope clock signal]11NV/OK is applied.
The output data of the inverter group 16 is incremented by 1, and the output data via the inverter group 16 is then decremented by 1.

The above-mentioned TGI consists of seven transfer gates, which are controlled to open and close by the zero point signal OGA which is the output of the waveform zero point detection section 8. The latch 17 takes in and latches the envelope data from the envelope counter 13 at the time of outputting the four-clock pulse φ, and provides the latch output to the multiplier 9 via an AND gate group AG3 consisting of seven AND gates. , and is fed back to the input terminal of the latch 17 via the gate (gate) Te3 consisting of seven transfer gates. The opening/closing of 'L'G2 is controlled by the output of the waveform zero point detection section 8 and the output of the zero point signal passed through the inverter 18.

For this reason, when the musical waveform reaches the zero point and there is an output from the waveform zero point detection section 8, the latch 17 opens the TG1 and takes in the envelope data, but at other times, it takes in the envelope data through the Te3. It keeps me coming back. Further, the AND gate group AG3 is controlled to open and close by the execute signal EXO from the control section 2. The multiplication section 9 multiplies the waveform data from the waveform ROM section 7 and the envelope data from the latch 17. The multiplication result data is given to the accumulator 19. The accumulator 19 sequentially accumulates the data provided by the multiplier 9 and provides the accumulated result data to the digital-to-analog converter (DAO) 2Q at the end of each cycle of the time-division processing operation. The digital-to-analog converter 20 converts the data given from the accumulator 19 into an analog/4G musical tone signal, amplifies it via the amplifier 21,
Sound is emitted from the speaker 22.

Next, the operation of this embodiment configured as above will be described.

First, when the power is turned on, the control unit 2 controls each latch 6.15.
A clock pulse φ is applied to 17. Then, by pressing a key on a keyboard (not shown), a reset signal π is output from the control section 2, and the AND gate groups AGI and AG2 are closed, all "0"s are taken into the latch 6.15, and then the control section 2, the preset signal PR is applied to the OR gate 11 of the waveform zero point detection section 8, and the OR gate 11 outputs a zero point signal to open the gate TGI. Then, since the outputs of the latch 15 of the envelope counter 13 are all "0", they are inverted by the inverter group 16, and all "1", that is, "1llllllJ" are taken into the latch 17 through the opened gate TGI.

Then, the output of the latch 6 is all rOJ, and the output of the AND gate 10 is also "0", so after the preset signal PR is output, the zero point signal OGA becomes "0", and the output of the AND gate 10 is "0".
'I! Gl is closed and G2 is opened instead. Therefore, the envelope data rl 111111J continues to be cyclically held in the latch 17 as shown in section 1 of FIG.

Then, the reset signal π is released and the animation group AG
1. AG2 is opened. And clock pulse φ4
Execute signal EXO at a rate of one per shot is sent to the control unit 2.
Then, the address data starts to be applied to the C terminal of the half adder 5 of the address counter 4, and the contents of the latch 6 are changed by sequentially adding "+1" to all "0" of the address data which is the output of the latch 6. waveform ROM accordingly.
The designated address of section 7 is incremented, and the waveform data sequentially read out thereby is supplied to multiplication section 9.

In this way, in the multiplication s9, the waveform data and the envelope data are multiplied, and then accumulated and D/A converted, and the musical tone is amplified and emitted.

During this time, the envelope clock signal ENV OK is sent to the C terminal of the half adder of the envelope counter 13.
is given, and the contents of the latch 15 are rewritten by sequentially adding "+1" to the output data of the latch 15, and accordingly, the envelope data output that has passed through the inverter group 6 is shown in Fig. 3 (A ) sequentially as shown in rl 1
11111'', l''1111110J, l'-1111
The count is decremented to 101J. However, since the game TGI is closed at this time, the envelope data is not taken into the latch 17 even though the envelope data is decremented as described above.

Then, the address counter 4 is incremented,
For example, the output of latch 6 is set to roll as shown in FIG.
When 11J is reached, the output of the AND gate 10 of the waveform zero point detection section 8 becomes "1" at the output timing of the execute signal EXO, the zero point signal OGA is output from the OR gate 11, and the gate) TGI is opened. Then, the envelope data rlloo that was being decremented at that time.

00" is taken into the latch 17, and immediately thereafter the execute signal EXO becomes "0" and the zero point signal OGA also becomes "0", so the gate 'I! Instead of GIG being closed, G2 is opened, so latch 1 is opened.
7, the envelope data "1100000J" continues to be circulated and held as shown in section 2 (0) of FIG.
continues to be given.

In this way, the address data is r o o o o o
From o o -1 to l'-0111111j,
In other words, while the musical sound waveform generates a half-period peak as shown in FIG. 3(E) and is emitted, the output of the envelope counter 13 is decreasing as shown in FIG. 3(A). The envelope data to be multiplied is shown in Figure 3 (0
), rllllllllj continues to be held,
The envelope data is switched for the first time when the musical sound waveform passes the zero point in half a period. This is the same even when the address data is [1111111J, that is, the zero point in the first period has passed, and the envelope data to be multiplied is the first one. As shown in 3ffi(0), the tone waveform switches only when it passes through the zero point, and becomes step-like in sections 3, 4, and so on. Therefore, the musical sound waveform will not be distorted.

In this embodiment, all the zero points of one waveform are detected and the envelope switching control is performed every half cycle, but it is also possible to detect one zero point in the - wave and control every half cycle. Of course. Furthermore, in the above embodiment, the present invention is applied to envelope control for the waveform of musical tones, that is, scale tones. The present invention can be similarly applied to.

〔Effect of the invention〕

As described above, since the present invention switches each state of the envelope at the zero point of the waveform, the waveform is not distorted and the generation of noise due to waveform distortion can be prevented.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a block circuit diagram of an electronic musical instrument equipped with an envelope control device, FIG. 2 is a specific circuit diagram of the envelope control device, and FIG. 3 is an actual circuit diagram of the envelope control device. FIG. 4 is a diagram showing the relationship between counted envelope data, musical sound waveforms, and multiplied envelope data. FIG. 4 is a time chart diagram of each part of the envelope control device of FIG. 2. 4...Address counter, 8...Waveform zero point detection section, 10...And gate, 11...
...OR gate, 13...Envelope counter, 17...Latch, TGl, '['G2
······Gate. Patent applicant Casio Computer Co., Ltd.

Claims (1)

[Claims] A device that performs envelope control of a waveform based on envelope data includes an envelope data generation means, a waveform zero point detection means, and when the waveform zero point detection means detects a zero point, the envelope data is fetched from the envelope data generation means and the next zero point is detected. 1. An envelope control device comprising means for performing envelope control using the envelope data until detection.