JPH0723840Y2 - Pitch converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a pitch conversion device for inputting a voice signal, converting the voice signal to a different pitch, and outputting the pitch.

[Prior Art] FIG. 3 shows a block diagram for explaining the principle of a pitch conversion device using a random access memory (hereinafter referred to as RAM) 4.

When an analog audio signal is input to the input terminal 1, the audio signal converted into a digital signal through a low pass filter (hereinafter referred to as LPF) 2 and an analog / digital converter (hereinafter referred to as ADC) 3 is converted into a write clock. It is written to RAM4 in synchronization with the signal. Thereafter, the digital signal is read from the RAM 4 in synchronization with the read clock signal, converted into an analog audio signal by the digital-analog converter (hereinafter referred to as DAC) 5 and LPF 6, and output from the output terminal 7. It

By making the frequency FI of the write clock signal and the frequency FO of the read clock signal different, the pitch of the analog signal output from the output terminal 7 can be made different from the pitch of the analog signal input to the input terminal 1. ,
The change amount P of the pitch is expressed by the following equation.

P = FO / FI The pitch conversion device as described above is also described in JP-A-60-184298.

Pitch conversion in such a pitch conversion device is performed by using an oscillator that generates a read clock signal as a voltage controlled oscillator and changing the voltage for controlling the oscillation frequency supplied to the oscillator using a variable resistor or the like. It is being appreciated.

[Problems to be Solved by the Invention] However, in the pitch conversion device as described above, when changing the pitch change amount P as the music progresses, the variable resistor must be adjusted as the music progresses.
There is a problem that the adjustment is troublesome. Furthermore, how much the pitch is changed to obtain the desired pitch change amount P,
However, there is a problem that the pitch cannot be easily changed unless the operator is familiar with the operation of the variable resistor. Especially, when the pitch change amount P is changed as the music progresses as described above, Even more so.

It is an object of the present invention to provide a pitch conversion device that solves the above problems.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention inputs a pitch conversion means for pitch-converting and outputting an input audio frequency signal at the same time as an input, and a signal representing a note name. Means, and the pitch conversion amount in the pitch conversion means based on the difference between the pitch name represented by the signal input by this means and the reference pitch name set independently of the input audio frequency signal. And means for setting.

[Operation] According to the present invention, in the state where signals representing various note names are input by the input means, when one of these note names is used as a reference, the other note names are the reference note names. It has several times the frequency. For example, if the reference pitch is the pitch of the pitch C, the pitch of the pitch G is a pitch having a frequency 1.5 times the pitch of the pitch P (pitch C). Therefore, when the setting means determines the input note name based on the reference note name,
Since the pitch change amount P can be determined, the pitch of the audio frequency signal that is being input to the pitch conversion means is converted and output at the same time as this input, based on the determined pitch change amount P. . It should be noted that, for example, when the pitch name G is specified by the inputting means, such pitch conversion is performed at a frequency of 1.5% of the frequency of the audible frequency signal input to the pitch converting means regardless of the frequency.
It is converted into a pitch having a doubled frequency and output (when the reference note name is note name C). That is, the pitch conversion amount is set regardless of the pitch of the input audio frequency signal, and the pitch conversion is performed.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram of a pitch conversion device according to an embodiment of the present invention, in which the same components as those in FIG. 3 are designated by the same reference numerals.

When an analog audio signal is input to input terminal 1, LPF2 and
The voice signal converted to a digital signal via ADC3 is
It is written in the RAM 4 in synchronization with the write clock signal output from the write clock generator 8. After this writing, a digital audio signal is read from the RAM 4 in synchronization with the read clock signal output from the read clock generator 10, converted into an analog audio signal by the DAC 5 and LPF 6, and output from the output terminal 7. . In this way, the audio signal is output at the same time as the input. The output analog audio signal has a pitch changed according to the ratio of the frequency FI of the write clock signal to the read clock signal FO.

Here, the write clock generator 8 generates a write clock signal, and its frequency FI is fixed.

Further, the read clock generator 10 generates a read clock signal, and its frequency FO is changed by changing the changeover switch 11, according to a signal set by the variable resistor 12, or by inputting a pitch control signal. Terminal 9
It is controlled according to the frequency of the signal input to. The pitch control signal input to the pitch control signal input terminal 9 can be an audio signal having a pitch, and for example, a musical tone signal of a musical instrument, a voice signal recorded on a tape recorder or the like is used.

The read clock signal is a frequency divider (hereinafter referred to as DIV) 1
3 is also input to the DIV 13, the read clock signal is divided into the audio band in the DIV 13, and is output from the clock signal output terminal 14 as a clock signal having a frequency corresponding to the read clock signal.

An example of a specific configuration of the read clock generator 10 is shown in FIG. This read clock generator 10 is a waveform shaping circuit.
The PLL circuit 103 includes a phase comparator 1 and a PLL circuit 103.
04, LPF105, voltage controlled oscillator (hereinafter referred to as VCO) 10
This is a well-known multiplication circuit composed of 6 and DIV107. In this read clock generator 10, the movable contact C of the changeover switch 11 is
Is connected to the fixed contact B, it is set by the variable resistor 12 regardless of the pitch control signal input to the input terminal 101 (corresponding to the pitch control signal input terminal 9 in FIG. 1). A read clock signal with a frequency that corresponds to the voltage
It oscillates in the VCO 106 and outputs it from the output terminal 108.

When the movable contact C of the changeover switch 11 is connected to the fixed contact A, the pitch control signal input to the input terminal 101 is input to the PLL circuit 103 via the waveform shaping circuit 102,
Here, it is multiplied, that is, a read clock signal having a frequency corresponding to the frequency of the pitch control signal is obtained, and the output terminal 108
Will be output.

In the above configuration, for example, the frequency FI of the write clock signal is set to 33.488 KHz, the division ratio of DIV13 is set to 1/128, and the division ratio of DIV107 is set to 1/32, and the movable contact C of the changeover switch 11 is set to the fixed contact A. And the pitch control signal input terminal 9 (corresponding to the input terminal 101 in FIG. 2) is connected to, for example, the output terminal of the keyboard instrument. Here, if the pitch is not changed, FO = FI may be set. Therefore, a key-the key of C ₆ of keyboard instrument. As a result, the pitch control signal input terminal 9
Is supplied with an analog pitch control signal having a fundamental frequency of 1046.5 Hz, the fundamental frequency is extracted by the waveform shaping circuit 102, and is multiplied by 32 by the PLL circuit 103.
It is set to 88 KHz and is supplied to the RAM 4 as a read clock signal.

Also, this read clock signal is divided into 1/128 by DIV13, and the basic frequency is 261.6H from the clock signal output terminal 14.
It is output as the z clock signal.

In the case of converting the pitch to the full 5 degrees above the input audio signal, FO should be set to FO = 50.165KHz which is 1.5 times FI. Therefore, it is completely 5 degrees higher than the reference pitch C ₆ .
When depressed the key of G _6, the pitch control signal input terminal 9,
By inputting an analog pitch control input signal whose fundamental frequency is 1567.6 Hz, the fundamental frequency of this is extracted by the waveform shaping circuit 102, and multiplied by 32 by the PLL circuit 103.
It is set to 50.165 KHz and is supplied to the RAM 4 as a read clock signal. Also, this read clock signal is 1 in DIV13.
It is divided into / 128 and output from the clock signal output terminal 14 as a clock signal having a fundamental frequency of 391.9 Hz.

If you want to change the pitch one octave higher, use FO
Should be 66.976KHz, which is twice the FI. Therefore, when depressed the C ₇ is the key to one octave than the reference pitch name C _6, the pitch control signal input terminal 9, the pitch control signal is supplied is fundamental frequency 2093Hz from the keyboard instrument, the basic The frequency is extracted by the waveform shaping circuit 102, multiplied by 32 in the PLL circuit 103, and supplied to the RAM 4 as a read clock signal of 66.976 KHz. Further, this read clock signal is divided into 1/128 by DIV13 and is output from the clock signal output terminal 14 as a clock signal having a basic frequency of 523.3 Hz.

By inputting the signal representing the note name to the pitch control input terminal 101 as described above in parallel with the input of the analog audio signal to the input terminal 1, the pitch can be converted and output.

The clock signals output from the clock signal output terminal 14 are C ₄ , G ₄ , and C ₅ , respectively, when expressed by note names.The commercially available automatic instrument tuner detects the fundamental frequency of the input audio signal. Since most of them can display the note name, by inputting the clock signal from the clock signal output terminal 14 to the automatic instrument tuner, the frequency of the write clock signal can be changed. , The tuner display shows C ₄ , unison (same tone), ie no pitch change, G ₄ shows full 5 degree pitch shift, C ₅ shows 1 You can see the pitch conversion on the octave. If the reference note name is selected as C in this way, the pitch change amount can be displayed as a note name based on this.

It is also possible to use an analog tone signal stored in a tape recorder or the like as the pitch control signal input to the pitch control signal input terminal 9, which has the advantage of not requiring a special storage device such as a sequencer. is there.

Further, in the present invention, the amount of change in pitch can be specified even with a MIDI signal that is a digital signal.

That is, the terminal 15 in FIG. 1 is a MIDI signal input terminal,
6 deciphers the MIDI signal input thereto and outputs a read clock signal FO corresponding to this MIDI signal. Since there is no regulation corresponding to the amount of change in pitch in the MIDI signal, the note-on message is used as a substitute for the designation signal of the amount of change in pitch P, with the sound of C as the reference, as in the case of the above analog signal input. That is, the change amount P when C is specified by the note-on signal is 0, the change amount P is high by 2 degrees (whole tone) when D is specified, and the change amount P is low by 2 degrees (semitone) when B is specified. Is the way.

When receiving this MIDI message, the CPU 16 divides the internal clock and outputs a read clock signal corresponding to the MIDI message. This read clock signal is RA
The audio signal, which is supplied to M4 and whose pitch is changed, is obtained from the output terminal 7, and at the same time, the read clock signal is divided into the audio band by DIV13. Therefore, as with the above example, the automatic instrument tuner is used. The pitch change amount P is displayed.

The switch 17 is a switch for selecting whether to adopt an analog input or a MIDI input. If there is a sequencer that stores MIDI signals, the pitch conversion amount P can be automatically specified by storing a predetermined note-on signal in this sequencer.

[Advantages of the Invention] In the pitch conversion device according to the present invention, a pitch name is input regardless of the pitch of the input audio frequency signal, and the setting means determines the pitch conversion amount based on the difference between this pitch name and the reference pitch name. Set,
It controls the amount of pitch change of the input audio frequency signal.
That is, the input of the pitch name is not for generating the pitch of the pitch name but for changing the pitch. Someone who has some knowledge of music understands how many times the pitch of another pitch name is based on a certain pitch name, so pitch conversion is easy. Can be performed. For example, as in the above embodiment, the note name C
Can be used as a reference. In this case, if the pitch is to be raised by a semitone, a signal representing the pitch name of C # may be input, and if the pitch is to be raised completely 5 degrees, then the pitch name is G.
It can be easily understood that the signal representing the signal can be input. Therefore, according to the pitch conversion device of the present invention, unlike the setting by the volume or the like, the pitch conversion amount can be set very easily by a simple operation of specifying a note name. In particular, in the case of the present invention in which the audio frequency signal is input to the pitch conversion means and is output at the same time, if the pitch conversion amount setting is frequently changed, it is easy to change the pitch conversion amount setting. The effect of a certain point is great. Further, since the signals representing these note names can be supplied from the outside through the input means, for example, a pitch control signal for designating a pitch conversion amount is stored as a note name in a sequencer, a tape recorder, or the like. By supplying this, pitch conversion can be automatically performed as desired in accordance with, for example, the progress of music supplied to the pitch conversion means.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a pitch conversion device according to the present invention, FIG. 2 is a block diagram of a read clock generator used in the same embodiment, and FIG. 3 is a block diagram explaining the principle of the pitch conversion device. Is. 4 ... RAM, 8 ... Write clock generator, 10 ... Read clock generator.

Claims (1)

[Scope of utility model registration request] 1. A pitch conversion means for pitch-converting and outputting an input audible frequency signal at the same time as input, a means for inputting a signal representing a note name, a note name represented by a signal input by this means, and the above-mentioned input. And a means for setting the pitch conversion amount in the pitch conversion means based on a difference from a reference note name set independently of the audio frequency signal.