JPH045195B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a musical tone frequency control device for an electronic musical instrument, which changes the amount of deviation depending on the pitch or range of a key when the musical tone frequency is slightly shifted from the normal frequency. . [Prior Art] In general, methods for shifting the frequency (pitch) of a musical tone from the normal frequency according to the pitch (or range) of the key include (a) the amount of frequency deviation (detune amount) for the musical tones of all keys; ) is kept constant (for example, about 2 Hz), and (b) there is a constant cent type, in which the frequency shift ratio is constant for all musical tones. If we take the pitch of the key on the horizontal axis and the amount of deviation (detune frequency) on the vertical axis, then the detune characteristic of the constant frequency type is as shown by symbol A in Figure 1, and the detune characteristic of the constant cent type is the 1st detune characteristic. It becomes something like the symbol B in the figure. However, in the constant frequency type, the ratio of frequency deviation to the normal frequency tends to be too large in a low temperature range, and too small in a high temperature range. On the other hand, in the constant cent type, the amount of frequency shift is too large in the treble range, and both types have the disadvantage that optimal frequency control cannot be achieved. Therefore, in order to realize the detune characteristic shown by symbol C in FIG. 1, a musical tone frequency control device having a configuration as shown in FIG. 2 can be considered. In other words, a multi-bit binary key code signal corresponding to the pitch of the pressed key output from the keyboard circuit 1.
KC is supplied to a frequency information conversion circuit 2, which converts the binary key code signal KC into frequency information F proportional to the pitch of the pressed key, and supplies it to an adder 3. On the other hand, as shown in Fig. 3, multiple sets of frequency control information ΔF correspond to multiple types of detune characteristics.
The binary key code signal KC and the detune information DD set by the performer are supplied as address signals to the detune memory 4 storing the
Frequency control information ΔF having characteristics corresponding to detune information D and corresponding to binary key code signal KC is generated, and this frequency control information ΔF is supplied to adder 3. As a result, the frequency information F is converted into the frequency control information ΔF by the addition (subtraction) operation of the adder 3.
is changed according to the value of Therefore, the changed frequency information Fq (=F±ΔF)
When this frequency information Fq is supplied to the tone generator 5, a musical tone signal having a pitch corresponding to this frequency information Fq and a tone corresponding to the tone color selection contents of the tone color selection circuit 6 is formed, and is emitted from the speaker 7. In other words, musical tones whose deviation from the normal pitch changes in accordance with the pitch of the pressed key in accordance with the detune characteristic shown in FIG. 3 are produced. However, in such a configuration, the frequency control information ΔF of various characteristics depending on the value of the detune information DD must be stored in the memory in advance, which requires a large capacity memory, leading to an increase in costs. There is. [Object and Structure of the Invention] The present invention has been made in view of the above-mentioned shortcomings of the prior art, and its object is to provide an electronic musical instrument that is inexpensive and can change the deviation amount of musical tone frequency according to the pitch or range of the key. An object of the present invention is to provide a musical tone frequency control device. To this end, the present invention generates logarithmic frequency information using a binary key code signal, and also forms a signal obtained by inverting at least a plurality of high-order bit signals of the key code signal or the frequency information. After changing the set value of the frequency shift amount using the inverted signal, it is added (subtracted) to the above frequency information, and the change in frequency information in response to changes in key pitch is made slightly more gradual than the normal one. By supplying frequency information of a logarithmic value with a gradual change like this to a logarithm/natural number conversion circuit, frequency information exhibiting characteristics as shown by symbol C in Fig. 1 can be obtained from this conversion circuit. be. [Embodiment] FIG. 4 is a circuit diagram showing an embodiment of the present invention, which includes a conversion circuit 10, an inversion circuit 11, and a multiplication circuit 1.
2, an addition circuit 13, and a logarithm/natural number conversion circuit 14. In such a configuration, the conversion circuit 10 generates a 7-bit key code consisting of a 3-bit block code BC representing the octave range of the pressed key outputted from the keyboard circuit, and a 4-bit note code NC representing the note. After receiving the signal KC, the note code of this key code signal KC is
After repeatedly adding the lower 2 bits of NC to the lower order of the lowest bit of the code NC, logarithmic frequency information consisting of 14 bits with this note code part as the decimal part and the above block code BC as the integer part is obtained.
form logF. The method of forming the above-mentioned frequency information logF in this conversion circuit 10 is described in Japanese Unexamined Patent Application Publication No. 1986-
Since it is described in detail in Publication No. 142397, the explanation here will be omitted. In addition, the conversion method for converting the key code signal KC into the frequency information logF in this conversion circuit 10 is not limited to the above-mentioned method. may be performed, and any method may be used. On the other hand, the inverting circuit 11 inputs and inverts the upper 5 bits of the key code signal KC, that is, the upper 2 bits of the block code BC and the upper 2 bits of the note code NC, to determine the pitch (range) of the key.
form an inverted signal' exhibiting a characteristic inversely proportional to,
The signal is supplied to the multiplier 12. The multiplier 12 modifies the detune information FD representing the amount of change in the frequency of the musical tone signal with respect to the normal frequency by a multiplication operation, and here, as shown in Tables 1 and 2, the most significant bit ( Detune information FD of 4 bits is input, with MSB) as a sign part (positive = "0", negative = "1") and its lower three bits as a numerical part.

【table】

〔Effect of the invention〕

As explained above, the present invention converts numerical information representing the amount of conversion of frequency information into numerical information that is inversely proportional to the pitch (range) of a key, and changes the logarithmic frequency information using this converted value. Since it is supplied to the natural number conversion circuit, it is possible to obtain frequency information with a simple circuit configuration in which the amount of change in the high range is slightly smaller than that of the constant cent type, making it possible to achieve optimal frequency control at low cost. There is an effect. Furthermore, since the musical tone frequency is controlled by changing the frequency information of the logarithmic value by adding and subtracting, for example, in order to obtain a constant cent type vibrato effect, it is only necessary to further add and subtract the vibrato control signal (specifically Specifically, in the above embodiment, the vibrato control signal is also input to the adder 13), which has the effect that various controls on musical tone frequencies can be easily carried out.

[Brief explanation of drawings]

Fig. 1 is a diagram showing frequency control characteristics by conventional frequency control technology, Fig. 2 is a diagram showing an example of a conventionally considered frequency control device, and Fig. 3 is a diagram showing the storage contents of the detune memory in Fig. 2. 4 is a circuit diagram showing an embodiment of the present invention, and FIGS. 5a to 5d are characteristic diagrams for explaining the operation of the embodiment. 10...Arithmetic circuit, 11...Inversion circuit, 12...
...Multiplication circuit, 13...Addition circuit, 14...Logarithm・
Natural number conversion circuit.

Claims (1)

[Scope of Claims] 1. A key code signal generation circuit that generates a binary key code signal consisting of a plurality of bits proportional to the pitch of a pressed key; a frequency information conversion circuit that converts the information into information and outputs the information; an inversion circuit that receives the key code signal or at least a plurality of upper bit signals of the frequency information, inverts the value of the bit signal, and outputs the inverted signal; and a musical tone. a first arithmetic circuit that multiplies a numerical signal representing a frequency change amount by an output signal of the inversion circuit; and a first arithmetic circuit that adds or subtracts the output signal of the first arithmetic circuit to the frequency information and outputs changed frequency information. and a logarithm/natural number conversion circuit that converts the changed frequency information into a natural number and outputs the converted frequency information, and is configured to control the frequency of a musical tone generated by the output information of the logarithm/natural number conversion circuit. A musical tone frequency control device for electronic musical instruments.