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Info: Biography, Pictures, Discography of all CDs & DVDs |
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| Development Tools and LanguagesMobile and Embedded Development.Int32 Shape of the modulation waveform.Remarks Can be set to one of the following: GargleEffect.IndustryMicrosoft partnersMicrosoft hardwareProduct catalogMactopiaMicrosoft.MarshalByRefObject implements IDisposable Members Table The following table lists the members exposed by the object.WaveTriangle Retrieves the value for a triangle modulation waveform for the EffectsGargle.Dispose Immediately releases the unmanaged resources used by the GargleEffect object.GetObjectByValue This member supports the infrastructure for Microsoft DirectX 9.Equality Compares the current instance of a class to another instance to determine whether they are the same.Inequality Compares the current instance of a class to another instance to determine whether they are different.Disposed Gets a value that indicates whether the object is disposed.Remarks Obtain this object by calling the GetEffects or GetObjectInPath method of a SecondaryBuffer object that is using the effect.Create and setup the sound device.Create and setup the buffer description.Create and setup the buffer for playing the sound.Check the Waveshape message board for the ID J Mag review!Waveshape002 is due for release 30th July '07 and will be popping up in shops with in the next couple of weeks.To select an entry, click on it.Click 'Go' if nothing happens.Explore over 30 doctoral specializations at Capella University."See a map of synonyms of waveshape in the Visual Thesaurus."This user has either cancelled their membership, or their account has been deleted.Id + " Text: " + targetLink.The desired waveshape is divided into a plurality of frames along a time axis and the exponent data is common in each individual one of said frames which includes a plurality of sample points.In this waveshape memory, the mantissa data corresponding to the respective sample points are stored in a first memory, and exponent data corresponding to the respective frames are stored in a second memory.Apparatus for generating the complement of a floating point binary number4383462May, 1983Nagai et al.Electronic musical instrument4442745April, 1984Gross et al.In an electrical musical instrument of the type wherein a complete musical waveshape is stored as sample points in a memory and read out to produce a musical tone, the waveshape sample points each being represented by a floating point number having a mantissa value and an exponent value, the improvement for memory size reduction wherein: the mantissa value of every sample point is stored in a separate memory location, and wherein for each group of sequential sample point values having the same exponent value, only one exponent value is stored, wherein each exponent value is stored in a separate memory location.In an electrical musical instrument of the type wherein a complete musical waveshape is stored as sample points in a memory and read out to produce a musical tone, the waveshape sample points each being represented by a floating point number having a mantissa value and an exponent value, the improvement for memory sizee reduction wherein: the mantissa value of every sample point is stored in a separate memory location, and wherein for each group of sample point value having the same exponent, the exponent value is stored only once, wherein each exponent value is stored in a separate memory location.BACKGROUND OF THE INVENTION This invention relates to a waveshape memory to be employed for an electronic musical instrument and other tone generation devices and, more particularly, to a waveshape memory storing waveshape data in a compressed form of representation and thereby enabling reduction in the required memory capacity.In a prior art waveshape memory for an electronic musical instrument, waveshape data is stored directly in linear or logarithmic representation format.This requires a large bit number resulting in increase in the memory capacity.If, particularly, waveshape data for one sample point is of a large bit number in a case where a tone waveshape signal of a high quality equivalent to a tone of a natural musical instrument is to be obtained by storing a full waveshape or a waveshape of plural periods from the start to the end of generation of a tone in a memory and reading the waveshape from this memory, the memory capacity as a whole becomes extremely large.An attempt to reduce the bit number of data for one sample point tends to reduce the dynamic range thereby impairing the tone quality of the tone produced.An electronic musical instrument of a type in which, in the above described manner, a full waveshape from the start to the end of generation of a tone is prestored for each key (note) in linear representation format and this waveshape is read out is disclosed in the specification of U.In the waveshape memory WM31 shown in FIG.SUMMARY OF THE INVENTION It is, therefore, an object of the invention to provide a waveshape memory capable of storing waveshape data in a data representation format according to which a sufficient dynamic range can be obtained with a relatively small bit number and thereby reducing the memory capacity without imparing the dynamic range of a waveshape signal.This arrangement enables reduction of the bit number per one sample point to a great extent while securing a sufficient dynamic range.This construction obviates the requirement for a large number of addresses corresponding to the respective sample points and only requires provision of a small number of addresses for the respective frames thereby contributing to reduction of the memory capacity of the waveshape memory as a whole.The waveshape memory according to the invention is applicable not only to an electronic musical instrument but to any other purposes.According to the present invention, the bit number of waveshape data for one sample point can be reduced to a large extent and yet a sufficient dynamic range can be secured whereby waveshape data of a high quality can be stored by a relatively small and economical memory.The division of the waveshape into mantissa and exponent can simplify the construction of a level coefficient operation circuit (i.DESCRIPTION OF PREFERRED EMBODIMENTS Storing of a tone waveshape of plural periods from the start to the end of generation of a tone will be described first.The full section of this tone waveshape is divided into a multiplicity of sample points in the known manner and amplitude values at the respective sample points are taken.The full section of this tone waveshape is divided into plural frames along the time axis (the number of frames is much smaller than the total number of sample points, e.With respect to the mantissa data and exponent data of the sample point amplitude values thus established, the waveshape memory is constituted by storing the mantissa data at sample point addresses corresponding to the respective sample points and the exponent data at the frame addresses corresponding to the respective frames.Examples of memory formats of this waveshape memory are shown in FIGS.At subsequent sample point addresses H+1 to I, I+1 to J, J+1 to K, K+1 to L, L+1 to M and M+1 to N corresponding to the frames 2 to 7 are stored, as illustrated, mantissa data M h +1 to M n corresponding to the respective sample points.In this embodiment, data for identifying the range of the sample point addresses corresponding to the respective frames is stored at the respective frame addresses.The sample point address range data, for example, are data indicating the last sample point addresses G, H, I, J, K, L, M and N in the respective frames.The waveshape memory 10 consists of a mantissa data memory 10A and an exponent data memory 10B.The address data generator 12 constitutes means for reading out waveshape data from the waveshape memory 10 in response to the tone pitch designated by the keyboard 11, particularly generating sample point address data sequentially changing at a rate corresponding to the designated tone pitch.KONP which is generated immediately upon depression of the key in the keyboard 11.Any known technique may be used for generating the address data in the address generator 12 so that detailed description thereof will be omitted.The sample point address range data read out from the memory 10B is applied to one input of the comparator 14 while the sample point address data from the address data generator 12 is applied to another input of the comparator 14.Thus the frame address data changes to "1" and data corresponding to the frame 1 is read out from the memory 10B while the contents of the counter 13 are not changed until the sample point address reaches the last address H in the frame 1.In the foregoing manner, the contents of the counter 13 do not change while the sample point address data generated by the address data generator 12 remains in the same frame and the frame address data corresponding to this frame is produced.Each time the frame to which the sample point address data belongs changes, the frame data also changes.Accordingly, actual data of the waveshape amplitude values can be identified by combinations of the mantissa data M (M 0 to M h ) at the respective sample points read out from the mantissa data memory 10A and the exponent data E (7 to 0) simultaneously read out from the exponent data memory 10B.When the count output of the counter 13 has become the maximum value "7", an AND gate 15 is enabled thereby stopping the counting operation of the counter 13.The mantissa data M and the exponent data E read out from the memories 10A and 10B are respectively applied to level controlling multiplier 16 and adder 17.KC of the depressed key as a parameter.The multiplier 16 multiplies the mantissa data M and M' together and the adder 17 adds the exponent data E and E' together (the addition of the exponents E and E' is substantially equivalent to the multiplication of 2 E and 2 E ').More specifically, although the mantissa data M when the exponent data E is "0" corresponds directly to the actual value, the mantissa data M when the exponent data E is other than "0" does not correspond to the actual value but data constituted by adding "1" to a higher bit of the mantissa data M corresponds to the actual value.By this arrangement, the continuity of the progression of the mantissa data M between the different values of exponent data E can be maintained.The memory 10B may store only the exponent data without storing the sample point address range data.In that case, the circuit for accessing the exponent data memory 10B may be modified to a circuit shown in FIG.This construction will enable further reduction in the bit number or further expansion in the dynamic range.In the above described embodiment, data for the respective sample point amplitude values of the tone waveshape over the full tone generation period (amplitude values themselves or difference values) is stored in the waveshape memory 10.The waveshape memory according to the invention is applicable not only to the above described tone waveshape but also to other desired waveshape including an envelope shape.In that case, a memory format and a reading system which are substantially the same as those in the above described embodiment may be employed.The electronic musical instrument comprises a function generator for generating a periodic function signal which includes the mathematical product of an amplitude term varying as a function of time and a cyclic term of a selected frequency, and a multiplier for modulating a part of the tone waveshape by the periodic function signal, thereby producing a musical tone signal changing in waveshape as time lapses.Images are available in PDF form when logged in.DIGITAL ORGAN3823390July, 1974Tomisawa et al.Electronic musical instrument employing waveshape memories3903775September, 1975Kondo et al.BACKGROUND OF THE INVENTION (a) Field of the Invention The present invention relates to an electronic musical instrument, and more particularly it pertains to a waveshape memory type electronic musical instrument which is provided with memory means for storing and reproducing the waveshape of tone signals.B) Description of the Prior Art In a waveshape memory type electronic musical instrument, a standard waveshape of a musical tone signal is preliminarily stored in a memory means and is read out upon each key depression at a speed corresponding to the pitch of the tone of the depressed key.An example of the waveshape memory type electronic musical instrument is shown in FIG.The R number is related with the pitch of the depressed key and is proportional to the fundamental frequency of the tone to be sounded.Thus, the adder 13 supplies the temporary sum to a waveshape memory 14 as its address signal.When the sum qR exceeds the modulus, the difference between the sum and the modulus remains in the adder 13.Then, similar cumulative addition is performed thereon.When the number of memory samples or stages in the waveshape memory 14 is equal to the modulus of the adder 13, the frequency of the waveshape produced from the waveshape memory 14 becomes equal to the aforementioned frequency f and is porportional to the magnitude of the R number.It will be seen that the repetition frequency f of the waveshape production represents the fundamental frequency of the musical tone to be sounded.On the contrary, when a small R number is generated, a musical tone of a low fundamental frequency is generated.The waveshape memory 14 stores the sample values of the waveshape of the musical tone in digital representation.Since the repetition frequency of the waveshape production is varied to be equal to the fundamental frequency of the musical tone to be sounded, the output of the waveshape memory 14 carries both the waveshape (i.Such a digital output signal of the waveshape memory 14 is multiplied by an envelope signal supplied from an envelope generator 15 in a multiplier 16.This analog signal is sounded as a musical tone from a loudspeaker 19 through an audio device 18 including an amplifier, etc.According to such a waveshape memory type electronic musical instrument, the amplitude of a tone is varied according to the envelope function generated from the envelope generator but the tone color is kept constant from the attack to the decay since the waveshape memory stores a predetermined waveshape and produces the same waveshape repeatedly.Such a constant color sound is far different from the rich sound of a natural musical instrument which changes the tone color delicately from the attack to the decay.Another object of the present invention is to provide a waveshape memory type electronic musical instrument capable of generating musical tones afforded with excess changes in the tone color and thereby exceeding the range of the musical tones of the natural musical instruments.According to the present invention, consideration is made on the following phenomenon occuring in the natural musical instruments.Namely, such natural musical instrument does not generate the same waveshape repeatedly, but it generates a waveshape which varies gradually from cycle to cycle.Furthermore, such changes in the waveshape occur only in a limited region of the whole one cycle of the waveshape.In the remaining region, the waveshape can be regarded as not varying with time.The changes in the waveshape of the musical tone as described above and hence the changes in the tone color enriches the expression of the musical tone of the natural musical instruments.The present invention is intended mainly to realize such changes.According to an aspect of the present invention, there is provided a waveshape memory type electronic musical instrument which generates a musical tone by reading out a waveshape memory which stores the sample values of the tone waveshape at a rate proportional to the pitch of the musical tone to be sounded, the electronic musical instrument comprising a function generator for generating a function waveshape, the amplitude of which being a function of time, and means for modulating a particular part of the tone waveshape with the function waveshape.BRIEF DESCRIPTION OF THE DRAWINGS FIG.Namely, a key depression in a keyboard 300 activates an R number memory 301 to generate an R number which is supplied to a cumulative adder 303 (having similar structure to the adder 13 of FIG.The output of the adder 303 calls the addresses of the waveshape memory 304 to read out the digital sample values constituting the waveshape of a musical tone.Such output of the waveshape memory 304 is supplied to the first multiplier 307 to be multiplied with the output of a function generator 305.Then, the output of the first multiplier 307 is supplied to a second multiplier 308 to be multiplied by the output of an envelope generator 306.Thus, the digital waveshape signal from the waveshape memory 304 is doubly multiplied by the outputs of the function generator 305 and the envelope generator 306 to form a digital tone signal.A) converter 309 and then it is sounded as a musical sound from a loudspeaker system 311 through an audio device 310 including an amplifier, etc.The detailed description will be made of the function generator 305 and the envelope generator 306, hereinbelow.R) as that for the waveshape memory 304.The first term in the righthand side represents a slowly varying constant term and the second term represents an oscillating term.When the waveshape memory 304 generates digital sample values constituting the tone waveshape W 0 of FIG.B, the first multiplier 307 forms the mathematical product of this waveshape W 0 and the output waveshape of the function generator 305 as shown in FIG.This product may have the waveshape as shown by W 1 , W 2 , W 3 , .Namely, the waveshape of the tone signal from the multiplier 307 changes with the lapse of time, taking the waveshape W 1 in the first period, the waveshape W 2 in the second period, the waveshape W 3 in the third period, and so on.The function generator 305 for generating such outputs may be formed of a circuit structure as shown in FIG.The respective constituents of the circuit of FIG.Namely, the gate 514 is controlled in the following manner.When the gate 514 is arranged to be opened by the positive logic (i.As will be described later, the first input signal Sa is the aimed value signal which is set according to the required function output and the second input signal Sb is the temporary value signal which is the output of the shift register 64.The output signal Sb of the shift register 64 forms the temporary value signal Sb which is subjected to the subtraction from the aimed value signal Sa in the subtractor 60.Since the temporary value signal Sb is fed back to the subtractor 60 at each timing of the clock pulse CK, the difference D between the signals Sa and Sb, which is the output of the subtractor 60, becomes successively smaller and hence the temporary value signal Sb approaches the aimed value signal Sa asymptotically.Sa, multiplication constant Sc for the multiplier 61 and the timing of the clock pulse CK.Sa, the multiplication constant Sc of the multiplier 61 and the timing of the clock pulse CK.Namely, in the block diagram of FIG.The circuit for setting the aimed value Sa includes an attack level setter 910 for setting the attack level La toward which the initial tone level grows, a sustain level setter 920 for setting the sustain level Ls toward which the tone level falls after the attack and at which it sustains, and a final level setter 930 for setting the final level Lf toward which the tone level falls and vanishes (refer to FIG.Among these level setters, the sustain level setter 920 may be formed of a plurality of ROMs which can be changed over by an operator through a manual switch provided in the operation panel of the electronic musical instrument or of a RAM which can be rewritten, so as to enable the change of the sustain level.The setting of the clock pulses CK is achieved on the basis of a pulse generator 950 for the attack envelope, a pulse generator 960 for the first decay envelope, and a pulse generator 970 for the second decay envelope.Selection of these clock pulses is achieved by the associated operation of the control logic circuit 900, AND circuits 951, 961 and 971 and an OR circuit 990.Generally speaking, it is preferable to set the pulse period for the attack envelope to be shorter than the pulse period for the first decay envelope and the pulse period for the first decay envelope to be shorter than the pulse period for the second decay envelope in order to generate a musical tone envelope resembling that of a natural musical instrument (especially piano).CR generated from the control logic circuit 900.The selection of the aimed value signal Sa and the clock pulse CK by the operation of the control logic circuit 900 will be described hereinbelow.The attack instruction signal AK opens the gate 911 and establishes the AND condition for the AND circuit 951 to select the attack level setter 910 and the pulse generator 950 for forming the attack envelope.OR circuit 990 as the clock pulse CK.La as the aimed value Sa and the pulse signal from the pulse generator 950 as the timing clock pulse CK.Sa, while the pulse output of the pulse generator 960 is supplied through the OR circuit 990 to the gate 62 as the clock pulse CK.KON vanishes and hence the control logic circuit 900 stops generation of the first decay instruction signal DY 1 and begins generation of the second decay instruction signal DY 2 .Thus, if the time length from the depression to the release of a key is short, the envelope ENV of FIG.Alternatively, if the timing of key depression is prolonged, the sustain state continues for a long time.As described above, upon release of the key, the second decay instruction signal DY 2 is generated from the control logic circuit 900 in place of the first decay instruction signal DY 1 .Then, the gate 931 is opened and the AND condition for the AND circuit 971 is established to select the final level setter 930 and the pulse generator 970 for forming the second decay envelope.Lf as the aimed value and the output pulse of the pulse generator 970 as the timing pulse CK.The exchange of the respective instruction signals from AK to DY 1 and from DY 1 to CR is achieved by the zero detection signal Z 0 which indicates that the output of the subtractor 60 has become "0."The operation of this control logic circuit 900 responding to the key operation will be described, while clarifying the structure of the envelope generator 306, hereinbelow.FF 6 is set, as shown in FIG.Description will be made in the operation order.AND condition for the AND circuit AND 6 does not hold.Thus, the AND circuit AND 6 generates "0" output.By the attack instruction signal AK which is held at "1" in the above manner, the attack envelope ENV 1 is formed.Thereby, the AND condition for the AND circuit AND 6 is fulfilled to supply "1" to the inverter INV 2 .FF 2 is reset to stop generating the attack instruction signal AK.Thus, the first decay instruction signal DY 1 is held to establish the first decay envelope ENV 2 as described above.Next, the manner of terminating the first decaying state by the key release will be described.KON vanishes by the key release as shown in FIG.Thus, the AND circuit AND 8 generates the output "1" (FIG.Here, it will be apparent that the AND circuit AND 7 generates no output opposite to the case of the key depression.This Q output is inverted by the inverter INV 3 and supplied to the AND circuit AND 3 .Although the amplitude of the tone signal waveshape was varied in a limited range of each cycle with the lapse of time in the above description, it may also be varied in response to the various parameters of the key depression such as the touch responsive signal representing the touch of the key operation and the tone pitch signal indicating what key of the keyboard is depressed.Therefore, musical tones extremely rich in tone color variation can be generated in a waveshape memory type electronic musical instrument.Previous Patent (Electronic musical i... |
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