JP3265706B2 - Crosstalk detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE et al provided in the present invention are adjacent to each other
The present invention relates to a crosstalk detecting device that detects a stroke phenomenon between the pickups .

[0002]

2. Description of the Related Art In order to detect string vibration for each string, there is known a stringed instrument provided with a string pickup (a converter for converting string vibration into an analog electric signal) for each of a plurality of strings. This kind of stringed musical instrument has a problem of a so-called crosstalk phenomenon that a string pickup generates an analog electric signal in response to vibration of an adjacent string because the string interval is relatively narrow.

A technique for analogly removing a crosstalk component from an analog electric signal output of a string pickup is disclosed in Japanese Utility Model Publication No. 58-4159. In this technique, an analog differential operation unit is provided corresponding to each string pickup, and an analog electric signal from the first (own) string pickup is input to a first input (−input) of each differential operation unit. ,
An analog electric signal from a string pickup adjacent to the first string pickup is input to a second input (+ input) of the differential calculator via a level conversion circuit. As a result, for the vibration of the adjacent string, the signal input from the adjacent string pickup to the second input of the differential operation unit and the crosstalk input from the own string pickup to the first input of the differential operation unit The signals become almost equal, and both signals are canceled in analog in the differential calculator. Therefore, it is possible to separately extract an analog electric signal due to the string vibration of each string from each differential calculator.

[0004]

However, the above prior art merely removes the crosstalk signal between the string pickups in an analog manner. For this reason, there is also a problem in terms of application that the analog electric signal extracted for each string is reproduced and output for each string, that is, it is limited to a so-called electric stringed musical instrument. Therefore, an object of the present invention is to provide a crosstalk detecting device capable of digitally detecting the above-described crosstalk phenomenon.

[0005]

According to the present invention, each other
Independently provided for each of a plurality of strings which are positioned adjacent to, to convert the vibrations of the respective strings and a plurality of pick-up means to pick up an analog electrical signal, the analog electrical signal by the pickup means into digital signals conversion means, pick-up hands adjacent from the converting means
Crosstalk determining means for determining the presence or absence of crosstalk by examining the relationship between digital signals related to the stage . According to this configuration, the pickup is caused by the vibration of the adjacent string.
The crosstalk signal mixed into the means can be digitally detected.

[0006] The above-mentioned crosstalk discriminating means is provided for an adjacent pick-up.
Vibration comparing the amplitude of the digital signals relating to up means
It may have width comparison means . For example, the amplitude of the digital signal of the first string pickup means (A) and pickup its neighboring
Taking the ratio between the amplitude (B) of the digital signal-flop means (A / B), when the ratio is smaller than a predetermined threshold value, to detect the digital signal of the first string pickup means as a cross-talk signal it can.

[0007] Further, the crosstalk discriminating means includes a
Power comparison means for comparing the power of the digital signal with respect to the pickup means may be included. For example, the power is (1)
Accumulation of digital signal sample values over a given interval,
It can be evaluated by (2) or square accumulation.

[0008] Further, the crosstalk discriminating means is provided for each of the adjacent crosstalk discriminating means.
It may include phase comparing means for comparing the phase of the digital signal with respect to the pickup means . With respect to the vibration of the string, the signals generated by the pickup of the string and the adjacent pickup have the same phase or the opposite phase (whether in-phase or opposite phase depends on the configuration conditions of both pickups.
By comparing the timing of the zero crossing point of the digital signal with respect to the pickup means, it is possible to check the phase for determining the crosstalk.

Further, peak crosstalk determination means adjacent
Pitch comparing means for comparing the pitch of the digital signal with respect to the backup means . The period (pitch) of the signal generated by the pickup of the string and the pickup next to the string due to the string vibration is obviously the same. Therefore,
By extracting pitches of digital signals related to adjacent pickups and comparing both pitches, it is possible to determine crosstalk. This configuration is particularly effective in applications such as a guitar synthesizer that generates a musical tone by an electronic sound source, and the pitch extraction function of the guitar synthesizer can be used for crosstalk determination. Each of the above-described means for determining the crosstalk can be used alone or in combination.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 shows an overall circuit configuration of an electric stringed musical instrument according to a first embodiment. The electric stringed musical instrument has a plurality of (for example, six) strings, and string pickups 1A to 1F for converting string vibrations into analog electric signals corresponding to each string are provided. Analog electric signals from the string pickups 1A to 1F are supplied to the amplifiers 2A to 2A, respectively.
After passing through F, the signal is sampled and held by a sample and hold circuit 3 having an analog multiplexer function for multiplexing analog electric signals by the number of strings, and is converted into a digital signal for each string pickup via an A / D converter 4. A /
The digital signal output of the D converter 4 is input to the vibration monitor circuit 5. The vibration monitor circuit 5 detects the string vibration level, peak, and time of the zero cross point of the digital signal relating to each string pickup, and provides the result to the CPU 6. The CPU 6 detects the start and end of the string vibration from the monitoring result from the vibration monitor circuit 5, and checks the relationship between digital signals related to adjacent string pickups to determine the presence or absence of crosstalk. When detecting the start of the string vibration, the CPU 6 writes the digital signal output of the A / D converter 4 relating to the string vibration into the string vibration RAM 7,
A write start command is given to the read / write control circuit 8. Here, the start of the string vibration is determined by whether or not the vibration level of the digital signal exceeds a predetermined threshold. The “start of string vibration” determined in this way is
(1) Not only is a vibration of a certain string detected from a digital signal formed from the pickup of the string via the A / D converter 4, but also (2) crosstalk, that is,
A / D converter 4 mixes with the pickup next to the string.
Can also be detected from the digital signal formed via.

In order to distinguish between (1) and (2), an appropriate time point (for example, 10 in FIG.
At the time of the first peak of the string vibration as indicated by 0), the presence or absence of crosstalk is determined. If the digital signal of interest is not due to crosstalk (case (1)), the CPU 6 gives a read start command to the read / write control circuit 8 for reproducing the sound of the digital signal. However, in the case of a digital signal due to crosstalk (case (2)), a read start command is not given to the read / write control circuit 8 to prohibit the reproduction of the digital signal.

The read / write control circuit 8 is a circuit for controlling access to the string vibration RAM 7 in a time division multiplexing (TDM) system. When a write start command is given from the CPU 6, the RAM 7 included in the command is included. From the address, the digital signal sample of the A / D converter 4 (related to the string pickup of interest) is written.
When a read start command is given from the CPU 6, the string vibration RA is read from the RAM 7 address (the same address as the write start command) included in the read start command.
The digital signal sample of M7 is read out.

A digital signal read out from the string vibration RAM 7 by the TDM method for each string is converted into an analog signal by a D / A converter 9 and each sample / hold circuit (S / H) 10
A to 10F. Thus, the S / H 10A samples and holds the first string analog signal, and similarly, the S / H 10B to S / H 10F sample and hold the second string to sixth string analog signals, respectively. Outputs of the sample hold circuits 10A to 10F are reproduced as sounds by the sound systems 11A to 11F.

FIG. 3 shows the CP when the vibration monitoring circuit 5 detects the string vibration level of the string that has been suspended until then.
It is a flowchart of the process performed by U6. First,
When the CPU 6 detects in step 3-1 that the string vibration level 3-1 has exceeded the threshold value, the CPU 6 proceeds to step 3-2.
And a write start process is executed. That is, the write pointer is set to the leading address of the string to be written into the RAM 7 with the vibration digital signal of the string of interest, and the write pointer and a write enable signal (A / D converter) for enabling the TDM channel of the string. ) To the read / write control circuit 8). In response, the read / write control circuit 8 sets the A / D converter 4 for the string (string pickup) of interest.
The above-mentioned writing is executed with respect to the digital signal from.
Then, the CPU 6 changes the string state flag M from "pausing" to "vibrating" (step 3-3). In addition,
The return from "vibrating" to "pausing" is performed when the string vibration level falls below a predetermined threshold.

FIG. 4 is a flowchart of a process executed by the CPU 6 when the vibration monitor circuit 5 detects a peak of a string whose status flag is "vibrating".

First, at step 4-1, the CPU 6 checks whether the string vibration peak is the first peak as shown by 100 in FIG. 2, and if so, executes the crosstalk test 4-2. If the digital signal based on the string pickup of interest is not a crosstalk (step 4-3), a read start process 4-4 is executed. That is, the read pointer is set to the same RAM 7 address as the write start address, and a read start command including the read pointer and the read enable signal is given to the read / write control circuit 8. In response, the read / write control circuit 8
Starts reading a digital signal related to the string pickup from the string vibration RAM 7. However, when it is not the crosstalk, the reading start process 4-4 is not executed, and the reading from the string vibration RAM 7 is thereby prohibited. Although not shown, for a string data channel for which no reading has been performed, D
All zero data indicating “silence” is output to the / A converter 9.

FIG. 5 shows a processing example of the crosstalk test 4-2.
FIG. First, at step 5-1 the CP
U6 reads the state flag of the adjacent string indicated by the string pickup adjacent to the string pickup of interest. If the state of the adjacent string is “resting”, “not crosstalk” (the signal generated by the focused string pickup is not crosstalk) is returned (5-7). If the adjacent string is not at rest, the vibration peak data (A) from the pickup of that string is read, and the ratio (A / B) to the signal peak data (B) of the pick-up of the string of interest is obtained. If this peak ratio exceeds a predetermined threshold value, "no crosstalk" is returned (5-7). If the peak ratio does not exceed the threshold, "crosstalk" is returned (5-8). Alternatively, a phase test (or a pitch test) may be performed as shown in step 5-6. Then, it can be determined in the phase test that the phase is not crosstalk if the phase is different, and that the phase is not crosstalk if the phase is different.

FIG. 6 shows a processing example of the phase test. First, in step 6-1, the CPU 6 determines the next string (string pickup).
Read the time data of the vibration peak (or zero crossing) point from. Next, at step 6-2, the corresponding time data from the current string pickup is read. Then, the time difference between the two time data is compared with a predetermined threshold value (6-3).
The phase test routine returns "in phase" if the time difference is smaller than the threshold (6-4), and returns "out of phase" if the time difference is larger than the threshold. It should be noted that "in-phase" in this processing example includes both the possibility of so-called two signals being in-phase and the possibility of being "out-of-phase".

FIG. 7 shows an example of a pitch test process. First, in step 7-1, the CPU 6 evaluates the vibration pitch of the adjacent string (string pickup). When the current string is an end string (first string or sixth string), there is only one adjacent string (second string or fifth string), but the current string is an intermediate string (for example, third string). In the case of a string, there are two (the second string and the fourth string). FIG. 7 shows P1 and P2 as pitch data of two adjacent strings. Next, in step 7-2, the vibration pitch data 90 of the current string is evaluated. The pitch evaluation need not be performed with high accuracy in the case of the first embodiment. For example, it is sufficient to calculate the time interval of the time data of the zero-cross point (or the peak point). In the case of the second embodiment (stringed musical instrument synthesizer) described later, the pitch extraction result of the pitch extracting function built in the stringed musical instrument synthesizer may be used.

In step 7-3, the difference between the pitch of the current string and the pitch of the adjacent string is compared with a predetermined threshold value. When the pitch difference is smaller than the threshold, the pitch test routine returns "same pitch" (7-4), and when larger than the threshold, returns "different pitch".

FIG. 8 shows a modification of the crosstalk test 4-2.
Shown in First, in step 8-1, the CPU 6 evaluates the vibration power of the adjacent string, and in step 8-2, evaluates the vibration power of the current string. The vibration power can be obtained, for example, by accumulating digital signal values (absolute values) in a section from the zero cross of the current string to the next zero cross. This corresponds to obtaining the waveform area X1 in FIG. The evaluation of the vibration power may be performed by the vibration monitor circuit 5 in order to reduce the load on the CPU 6. Further, it is not necessary to be a section from zero cross to zero cross, and as a simple method, accumulation of predetermined N digital values is sufficient. Step 8-
At 3, the CPU 6 compares the ratio of the two powers (the power of the current string / the power of the adjacent string) with a predetermined threshold value. When the power ratio exceeds the threshold, the cross test routine returns "no crosstalk" (8-4), and when the power ratio is below the threshold, returns "crosstalk" (8-5). .

Second Embodiment A second embodiment is an example in which the present invention is applied to a stringed musical instrument synthesizer. FIG. 9 shows the overall circuit configuration of the second embodiment. In addition, the same elements as those in FIG.
Description is omitted. The TDM digital signal of each of the string pickups 1A to 1F is output from the A / D converter 4 to a level detector 5M.
Is input to the pitch extractor 12. The level detector 5M detects the string vibration level of each string (string pickup). The pitch extractor 12 extracts a vibration pitch of each string. As the pitch extractor 12, a known suitable pitch extractor in a stringed musical instrument synthesizer can be used. The CPU 6 performs the above-described crosstalk test when the first pitch determination signal is given from the pitch extractor 12 for each string. I do. On the other hand, when it is determined that there is a crosstalk, no tone generation instruction is issued to the sound source 13.
The signal is input to the sound system 15 via the / A converter 14 and reproduced as sound.

As a result, the crosstalk signal generated in the string pickup due to the vibration of the adjacent string causes the sound source 13
Is generated, and a corresponding tone is generated from a normal signal generated in the string pickup by the vibration of the own string, with the first pitch determination in the pitch extractor 12 as a signal. After that, it operates in the same manner as a normal stringed musical instrument synthesizer. That is, when a corresponding pitch change process from the CPU 6M to the sound source 13 is performed in response to the extraction of a new pitch in the pitch extractor 12, and the level detector 5M detects that the vibration level has dropped below a predetermined threshold value. , The CPU 6M mutes the corresponding musical sound in the sound source 13.

As described above, the digital crosstalk detection technique according to the present invention can be effectively applied to an electronic musical instrument having a built-in electronic sound source, such as a stringed musical instrument synthesizer. The description of the embodiment has been finished above, but various modifications and applications are possible within the scope of the present invention.

For example, (1) Test of peak ratio (5-3
5-4) (2) Phase test (FIG. 6) (3) Pitch test (FIG. 7) (4) Power ratio test (FIG. 8) is used alone or in an appropriate combination for discrimination of crosstalk Can be used. Also, the illustrated flow is merely an example, and can be appropriately modified.

[0026]

As described above in detail, according to the present invention, the analog electric signal from each independently provided pickup is converted into a digital signal, and the relationship between the digital signals related to the adjacent pickups is converted. , The presence or absence of crosstalk is determined, so that digital crosstalk can be detected, and there is an advantage that the range of application is widened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall circuit configuration of a first embodiment.

FIG. 2 is a waveform diagram of an analog electric signal extracted from a string pickup.

FIG. 3 is a flowchart including a writing start process.

FIG. 4 is a flowchart including a reading start process.

FIG. 5 is a flowchart illustrating an example of a crosstalk test.

FIG. 6 is a flowchart illustrating an example of a phase test.

FIG. 7 is a flowchart illustrating an example of a pitch test.

FIG. 8 is a flowchart showing a modified example of the crosstalk test.

FIG. 9 is a block diagram showing the overall circuit configuration of the second embodiment.

[Explanation of symbols]

 1A to 1F String pickup 4 A / D converter 6 CPU

Continuation of the front page (56) References JP-A-4-242796 (JP, A) JP-A-2-216197 (JP, A) JP-A-6-12063 (JP, A) JP-A-1-279297 (JP) , A) Jiko 7-101343 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G10H 3/18 G10H 1/00

Claims (6)

(57) [Claims] (1)Placed adjacent to each otherEach of multiple strings
Provided independently of each other,TheAnalog electric vibration of each string
Pick up as signalMultiple pickup means
And digitally converting the analog electric signal into pickup means.
Conversion means for converting into a signal;this Neighbor from conversion meansPickup meansAbout
Examine the relationship between digital signals to determine the presence or absence of crosstalk.
A crosstalk detecting device, comprising: a different crosstalk determining unit. 2. An analog electric signal is independently picked up.
A plurality of independently provided pins adjacent to each other
Backup means and digitally separate the analog electric signals by pickup means.
Conversion means for converting into a signal, and adjacent pickup means from this conversion means
Examine the relationship between digital signals to determine if crosstalk exists.
A crosstalk determining unit for digitally determining the crosstalk . 3. A cross-talk detection apparatus according to claim 1 or 2, wherein the crosstalk determination means, pick-up adjacent the hand
A crosstalk detecting device comprising an amplitude comparing means for comparing the amplitude of a digital signal related to a stage . 4. A cross-talk detection apparatus according to claim 1 or 2, wherein the crosstalk determination means, pick-up adjacent the hand
Power comparison comparing the power of digital signals for stages
A crosstalk detection device comprising: 5. A cross-talk detection apparatus according to claim 1 or 2, wherein the crosstalk determination means, and further comprising a phase comparator means <br/> for comparing the phase of the digital signal related to the pickup means adjacent Crosstalk detector. 6. A cross-talk detection apparatus according to claim 1 or 2, wherein the crosstalk determination means, pick-up adjacent the hand
Pitch comparison comparing the pitch of digital signals for stages
A crosstalk detection device comprising: