Electronic stringed instrument with fingering operating data memory system and navigate display device

In an electronic stringed instrument, when a fingered string is plucked, the initiation of vibration of the plucked string is detected by a string vibration sensor to generate timing data representing the vibration initiation timing and number data representing the number of the string which is vibrated. Every time the timing data is obtained, pitch data, timing data and number data are respectively stored in the memory.

BACKGROUND OF THE INVENTION 
In recent times, various electronic musical instruments have been developed 
which utilize advances made in electronic technology. Among these 
electronic musical instruments are electronic stringed instruments such as 
electronic violins, electronic guitars, and guitar synthesizers, as well 
as electronic keyboard instruments such as electronic pianos and 
electronic organs. 
An electronic stringed instrument is usually played by designating a 
desired pitch with a finger, while picking strings with another finger, 
thereby producing a desired musical sound. Consequently, more advanced 
performance techniques are required on the part of the player than in the 
case of playing an electronic keyboard instrument. In particular, when 
playing a guitar, in order to quickly and reliably produce a number chords 
which occur frequently in a piece of music, a plurality of strings have to 
be picked while a corresponding number of strings are simultaneously held 
depressed. Since it is extremely difficult to master such advanced 
performance techniques by self-teaching, it is therefore necessary for the 
player to receive special training or personal teaching from a qualified 
teacher. 
A musical instrument training device is disclosed in U.S. Pat. 
Specification No. 4,286,495. In this device, when a chord name, e.g., Am 
or C.sub.7, is designated by selectively operating a chord selection 
switch provided on a guitar body, one of a plurality of LEDs 
(light-emitting diodes) provided on respective fret positions on a 
fingerboard, i.e., a LED provided at fret positions corresponding to the 
designated chord name, is turned on to designate the fret positions at 
which strings are to be held depressed. 
In this disclosed training device, however, only a fret position 
corresponding to a selectively operated chord selection switch is 
designated with the turning-on of the LED provided at the corresponding 
fret position. In other words, it is not possible to display the finger 
operating position, finger operating order, finger operating direction, 
etc. with the progress of music being played. Further, with regard to the 
training device noted above, no judgment is made on whether strings have 
been correctly depressed by the player at the position, at which LEDs 
corresponding to the chord name selected by a chord selection switch are 
indicated. This means that the device is inadequate as a means of training 
a player, since it does not check as to whether strings are correctly 
depressed at the position at which an LED is turned on. 
Japanese Patent Laid-Open 54-161924 discloses an electronic stringed 
instrument, in which pitch data, corresponding to a fret position, at 
which strings are being depressed, is stored in advance, the stored pitch 
data being then read out and sounded for every picking of the strings. As 
a result, it is possible to sound musical notes of desired pitches at 
desired timings. 
With this electronic stringed instrument, however, tone length data is not 
stored in addition to the tone pitch data. More particularly, when an 
actual performance is made, the performance content is not stored in real 
time. Consequently, it is not possible to reproduce the performance 
content in the same manner in which it was played. This means that it is 
not possible to improve the playing techniques by finding mistakes in the 
playing for instructional purposes while reproducing the stored 
performance. Further, with this electronic stringed instrument, navigation 
display is not made on the basis of the stored pitch data. Therefore, 
training of playing techniques can not be made with this stringed 
instrument. 
SUMMARY OF THE INVENTION 
This invention has been developed with the intention of solving the various 
problems, noted above, associated with the prior art. An object of the 
invention, accordingly, is to provide an electronic stringed device, which 
permits navigation display of at least either operating position, 
operating order, operating direction or operating tempo of the play in 
timed relation to the progress of a piece of music being played, so that 
it is possible to expect improvement of the player's technique to be 
attained reliably in a short period of time. 
Another object of the invention is to provide an electronic stringed 
instrument, which permits a performance to be stored in real time and the 
stored performance to be reproduced in real time so that it is possible to 
find mistakes in the performance for instructional purposes while checking 
contents of performance. 
A further object of the invention is to provide an electronic stringed 
instrument, in which the operation contents of the performance by the 
performer are stored in real time, and the particular notes to be played, 
in order, are displayed by navigation display in a timed relation to the 
progress of the stored "correct" performance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Now, an embodiment of the invention will be described in detail with 
reference to the accompanying drawings. 
CONSTRUCTION 
FIG. 1 is a plan view showing an electronic stringed instrument according 
to the invention. The stringed instrument consists of neck 1 and body 2. 
Neck 1 has fingerboard 1a. Six fret strings 3 are stretched along 
fingerboard 1a for guiding fingers to desired fret positions at the time 
of the fingering. Six trigger strings 4 are also stretched along barrel 2 
to be operated during a performance. 
Fret strings 3 each have one end secured for adjustment to peg 6 provided 
on head 5 of neck 1 and the other end secured to peg 7 provided adjacent 
to a juncture portion between fingerboard la and body 2. Head 5 of neck 1 
is provided with LCD section 8, on which chord names, e.g., Am, C.sub.7, 
etc., and note names, e.g., C, A, etc., are displayed. 
16 frets 9 are provided at predetermined intervals on fingerboard 1a. Pitch 
designation switches PSW are provided between adjacent frets 9 on 
fingerboard 1a corresponding to each individual fret string 3. In this 
instrument, 15 (number of spaces between adjacent frets 9) by 6 (number of 
trigger strings), i.e., 90, pitch designation switches PSW are provided. 
Fret LEDs 10 (shown in FIG. 2) are provided above each of the pitch 
designation switches PSW. Fingering positions corresponding to pitch 
designation switches PSW to be operated are shown visually with the 
turning-on of fret LEDs 10. 
The six trigger strings 4 are stretched between bridges 11 provided in a 
spaced-apart relation on body 2 with their opposite ends secured to 
bridges 11. Six trigger switches TSW are provided, each at one end of each 
trigger string 4. Six trigger LEDs 12 are provided on body 2, under the 
central portion of each trigger string 4. With selective turning-on of 
trigger LEDs 12, for the strings among six trigger strings 4 to be picked, 
the direction of picking or tempo of picking is shown visually. As for 
picking techniques, there are down-picking, in which the trigger strings 4 
are picked in the downward direction of arrow A, up-picking in which the 
trigger strings 4 are picked in the upward direction of arrow B, and 
alternate picking, in which down-picking and up-picking are repeated 
alternately. For the tempo of picking, there are double times and triple 
times. 
Body 2 is provided with mode switch 13, power switch 14, tempo knob 15 and 
cassette setting section 16. Mode switch 13 is used for switching the play 
mode of the electronic stringed instrument to a recording mode, a playback 
mode, a navigation mode, a picking mode and a metronome mode. The 
recording mode is set for recording the fingering and picking in a real 
time recording section. The playback mode is set for playing back the 
performance recorded in the real time recording section. The navigation 
mode is set for indicating fingering positions of pitch designation 
switches PSW to be operated while selectively driving fret LEDs 10, and 
trigger LEDs 12 for indicating which of trigger strings 4 should be 
picked, and in what order. The picking mode is set for indicating the 
direction of picking of trigger strings 4 by selective driving of trigger 
LEDs 12. The metronome mode is set for indicating the tempo of play while 
driving trigger LEDs 12 in reciprocal directions in a timed relation to a 
preset tempo as in the case of the alternate picking. Power switch 14 is 
for turning off the power source. Tempo knob 15 is operated for selecting 
the tempo. In the card setting section 16, ROM card 17, on which play data 
has been recorded, or RAM card 17, on which play data of a performance by 
a performer has been recorded in real time, is set. 
CONSTITUTION OF PITCH DESIGNATION SWITCHES PWS 
FIG. 2 is a fragmentary sectional view of neck 1. Pitch designation 
switches PSW are inlaid in neck 1. These pitch designation switches PSW 
each consist of fixed contact 18 and variable contact 20. Fixed contact 18 
is secured to the under-side of flexible sheet 19 provided over the entire 
surface of fingerboard 1a. Flexible sheet 19 consists of rubber and 
elastic plastic material. Flexible sheet 19 has raised portions each 
corresponding to each fixed contact 18, and movable contact 20 is mounted 
on the underside of each raised portion. Spacers 21 are provided in 
portions on flexible sheet 19 other than the raised portions. Protective 
plates 22 are secured to the top of spacers 21. Frets 9, described above, 
are each provided on protective plate 22 right above spacer 21. Protective 
plate 22 is formed with holes 23 in rows of six holes each provided 
between adjacent frets 9. Transparent key top 24 is fitted for vertical 
movement in each hole 23. When key top 24 is pushed down together with 
fret string 3, movable contact 20 of flexible sheet 19 is selectively 
brought into contact with fixed contact 18. As a result, a corresponding 
pitch designation switch PSW is turned on, and a pertinent pitch 
designation signal is supplied to a CPU, to be described later. 
In each key top 24, fret LED 10, described above, is accommodated. A 
turn-on signal is supplied to fret LED 10 from a conductive line (not 
shown) formed on the upper surface of flexible sheet 19 or lower surface 
of protective plate 22. According to this turn-on signal, each fret LED 10 
is selectively driven to emit light indicating a fingering position of a 
pitch designation switch PSW to be operated. Fret strings 3 are not 
essential and may be omitted. 
CONSTITUTION OF TRIGGER SWITCHES TSW 
FIG. 3 is a sectional view showing trigger switch TSW and trigger LED 12, 
noted above. Trigger switch TSW consists of conductive trigger string 4 
constituting one contact member, conductive coil spring 26 constituting 
the other contact member, and insulating member 25 for electrically 
insulating trigger string 4 and coil spring 26 from each other. Trigger 
switch TSW is coupled to each of six trigger strings 4. The construction 
of the trigger switch TSW will now be described in detail. Cylindrical 
insulating member 25 is secured to conductive trigger string 4. A stem 
portion of conductive coil spring 26 is fittedly supported on the outer 
periphery of insulating member 25. While trigger string 4 is stationary, 
the free end of coil spring 26 is spaced apart from conductive trigger 
string 4, so that trigger switch TSW remains "off". When trigger string 4 
is operated, i.e., when trigger string 4 is pulled from the stationary 
state and then released, the free end of coil spring 26 is brought into 
electric contact with trigger string 4, as shown by dashed lines in FIG. 
3, for it can no longer follow the movement of trigger string 4. Thus, 
trigger switch TSW is turned on. Part of coil spring 26 is pulled out to 
the outside from its stem portion and connected to input section 31 to be 
described later. Through this coil spring 26, an "on" signal of trigger 
switch TSW is transmitted as musical sound trigger data to input section 
31. 
Trigger LEDs 12, noted above, are provided on body 2 under the central 
portion of trigger strings 4. The order of trigger strings 4 to be picked, 
the direction of picking or tempo of picking is indicated by the 
turning-on of trigger LEDs 12. 
CONSTITUTION OF ENTIRE CIRCUIT 
FIG. 4 is a block diagram showing the circuit construction of the 
electronic stringed instrument according to the invention. Input section 
31 consists of a plurality of pitch designation switches PSW for producing 
pitch designation signals FC and six trigger switches TSW for producing 
musical sound trigger signals Ts. Play data is constituted by pitch 
designation signals and musical sound trigger signals provided from input 
section 31. In the recording mode, the play data is written in the form of 
note code, tone length code and picking data in ROM/RAM card 17 in ROM/RAM 
card section 33 under write control of real time recording section 32. In 
this case, write address data is supplied from real time recording section 
32 to ROM/RAM card section 33. 
In the navigation mode and metronome mode, play data stored in ROM/RAM card 
17 of ROM/RAM card section 33 is read out. The note code of the play data 
is supplied to LCD section 8, fret LED section 34 and trigger LED section 
35. According to the note code supplied to LCD section 8, corresponding 
note name and chord name are displayed on LCD section 8. According to the 
note code supplied to fret LED section 34 and trigger LED section 35, 
corresponding fret LEDs 10 and trigger LEDs 12 are turned on to indicate 
the order of fingering positions of pitch designation switches PSW and 
direction of picking. 
In the recording mode or navigation mode, the play data provided from input 
section 31 in response to the pitch designation operation on finger-board 
1a and musical sound trigger designation operation on trigger strings 4 is 
converted through key code generation circuit 36 into corresponding key 
code. The key code thus generated is supplied through CPU 37 to sound 
source circuit block 38, which generates a corresponding musical tone to 
be generated. In the playback mode, the play data read out from ROM/RAM 
card 17 in ROM/RAM card section 33 is converted through key code 
generation circuit 36 into a corresponding key code. The key code is 
supplied through CPU 37 to sound source circuit block 38 for generating 
and sounding the corresponding musical tone. CPU 37 supplies various 
control signals to the circuit shown in FIG. 4. 
CONSTITUTION OF INPUT SECTION 31 
FIG. 5A shows a specific construction of input section 31. 
Input section 31 consists of trigger switches TSW and pitch designation 
switches PSW. An "on" signal supplied from trigger switches TSW is 
supplied as set (S) signal in RS-type flip-flops Fl to F6. The Q output of 
flip-flops Fl to F6 is provided as musical sound trigger signal. The Q 
output of each of flip-flops F1 to F6 is supplied through OR gate 01 to 
timer circuit 39 as driving start signal to start driving of timer circuit 
39. A time-up signal provided from timer circuit 39 after time counting is 
supplied as reset (R) signal to each of flip-flops F1 to F6. Thus, the 
"on" signal supplied from trigger switches TSW to flip-flops F1 to F6 is 
sampled for every timer time. This is done so in order to prevent 
unnecessary generation of musical sound trigger signal due to turning-on 
of trigger switches TSW a plurality of times at the time of one picking 
operation on trigger strings 4. In other words, this is done in order to 
prevent chattering. Therefore, even if the same "on" signal of trigger 
switch TSW is supplied consecutively during the time counting of the timer 
circuit 39 so that a driving start signal is supplied to timer circuit 39, 
timer circuit 39 can continue the counting. This, an "on" signal of 
trigger switch TSW supplied to each of flip-flops F1 to F6 during the time 
counting of timer circuit 39 is a signal supplied simultaneously with the 
"on" signal of this time and is dealt with as an ineffective trigger 
signal. The trigger signal supplied from the same trigger switch TSW after 
completion of the time counting of timer circuit 39 is processed as an 
effective musical sound trigger signal. It is thus guaranteed that when 
one picking operation is executed, the first trigger signal is supplied as 
an effective musical sound trigger signal to CPU 37. It is detected as 
pitch designation signal Fc according to a key sampling signal from key 
scan circuit 40 controlled by CPU 37. This pitch designation signal Fc is 
provided as a fret code from key scan circuit 40. This fret code is 
expressed as 4-bit digital data, as shown in FIG. 5B. The fret code can 
assume values from "0000" (indicating the open fret string position) to 
"1111" (indicating the fifteenth fret position) for digitally expressing 
each fret position from the open string fret position to the sixteenth 
fret position. 
CONSTRUCTION OF PORTION FOR GENERATING AND SOUNDING MUSICAL TONES 
The musical tone generating/sounding section sound source circuit 38 for 
generating a musical sound signal according to a key code, an amplifier 42 
and a loudspeaker 43 for amplifying and sounding a musical sound signal 
provided from sound source circuit 38. 
The musical sound trigger signal and fret code from input section 31 are 
supplied to a key code generation circuit 36. Key code generation circuit 
36 converts the fret code to a corresponding key code for every timing of 
input of musical sound trigger signal. This key code is supplied through 
CPU 37 to sound source circuit block 38. Sound source circuit 38 generates 
a corresponding musical sound signal. This musical sound signal is 
amplified through amplifier 42 and sounded from loudspeaker 43. 
The state of operation of mode switch 13 and tempo knob 15 on body 2 is 
detected by CPU 37. The result of detection is provided as various control 
data from CPU 37. 
CONSTITUTION OF ROM/RAM CARD SECTION 33 
FIG. 7A shows the construction of ROM/RAM card section 33. 
ROM/RAM card section 33 comprises ROM/RAM card 17 including a portion where 
play data has been stored in advance and a portion where play data can be 
stored in real time, address control circuit 46 for effecting address 
control by reading out play data from ROM/RAM card 17, write buffer memory 
44 and read buffer memory 47. ROM/RAM card 17 is used for the recording 
mode, playback mode (i.e., automatic play mode), navigation mode, picking 
mode and metronome mode. 
When the Recording Mode is Set 
Data of actual play by a performer is supplied from input section 31 to 
real time recording section 32. The play data (i.e., note code, interval 
code and picking data) supplied to a read/write control section (to be 
described later) in real time recording section 32 is once set in write 
buffer memory 44 and is then written through interface 45 into ROM/RAM 
card 17. FIG. 7B shows the contents of play data written in the ROM/RAM 
card. In this case, address control circuit 46 is controlled by real time 
recording section 32. A write address signal provided from address control 
section 46 is supplied through interface 45 to ROM/RAM card 17. 
When the Navigation, Picking and Metronome Modes are Set 
The play data sorted in ROM/RAM card 17 is read out by the action of 
address control circuit 46. In the navigation, picking and metronome 
modes, the play data read out from ROM/RAM card 17 is supplied to fret 
side LED section 34 and trigger LED section 36, whereby the fingering 
position of fret strings 3, the order of operation of trigger strings 4, 
the direction of operation and the tempo of operation are indicated by 
selective turning-on of LEDs 10 and 12 by the action of LED sections 34 
and 35. The note code that is contained in the play data string codes 
"000"to "110" digitally expressing the first to the sixth ones of trigger 
strings 4 and fret codes "0000" to "1111" digitally expressing the open 
string fret position and the first to the fifteenth fret position as shown 
in FIG. 5B. The note code (string code and fret code) is supplied to fret 
LED section 34, but only the string code is supplied to trigger LED 
control section 35. This data configuration is by no means limiting, and 
it is possible to adopt any other suitable data configuration. 
The note code and picking data read out from read buffer memory 47 are 
supplied as display data of each fret LED 10 to fret code generation 
circuit 48. Fret code generation circuit 48 extracts only the fret code 
corresponding to each fret position, as shown in FIG. 5B. The fret code is 
supplied to coincidence circuits 49 for respective six strings, i.e., 
first to sixth fret strings 4. The allotment of fret codes to coincidence 
circuits 49 is done according to the string code in the note code. To 
coincidence circuits 49 is also supplied the fret code supplied from input 
section 31. When the fret code provided from ROM/RAM card 17 and fret code 
provided from input section 31 coincide, i.e., when a pitch designation 
switch PSW belonging to the fret position corresponding to the turned-on 
fret LED 10 is operated, a coincidence signal is supplied through AND 
gates A1 to A6 to AND gate A7. AND gates A1 to A6 are enabled by "on" 
signals from trigger switches TSW corresponding to picking operation of 
each trigger string 4. Coincidence circuits 49 effect coincidence judgment 
with respect to any open string condition where a corresponding fret 9 is 
not depressed. When coincidence of both fret codes is obtained for all the 
strings and corresponding trigger switches TSW are turned on, an all 
string coincidence signal is supplied as a set (S) signal from AND gate A7 
to RS-type flip-flop F7. The Q output of flip-flop F7 is supplied as an 
enable signal to AND gate A8. 
To AND gate A8 is also supplied as an enable signal a navigation mode 
signal when the navigation mode is set by mode switch 13. The tone length 
code read out from read buffer memory 47 is set in timer circuit 50, which 
executes time counting according to the tone length code. A time-up signal 
provided from timer circuit 50 after the time counting is supplied through 
AND gate A8 and OR gate 02 to address control circuit 46. The read address 
of ROM/RAM card 17 is incremented by the time-up signal. 
Thus, in the navigation mode, when and only when the tone length 
corresponding to the tone length code has passed from the instant of the 
reading of play data of this time from read buffer memory 47 and accurate 
picking of trigger strings is done with depression of correct fingering 
position, the reading of the next play data is performed. The coincidence 
of this play data and play data from input section 31 is done by 
coincidence circuits 49. The output of AND gate A8 is supplied as reset 
(R) signal to flip-flop F7. Thus, flip-flop F7 waits for the coincidence 
signal based on the next play. 
The time-up signal from timer circuit 50 is supplied through address 
control section 46 through AND gate A9 and OR gate 02. The read address of 
ROM/RAM card 17 is incremented by an address control signal supplied from 
address control section 46. As a result, the next play data is read out. 
When the Playback Mode is Set 
At the time of the playback mode (i.e., automatic play mode), the play data 
read out from ROM/RAM card 17 is supplied to CPU 37, and according to the 
play data musical sounds are produced from sound source circuit block 38. 
In this case, during a period from an instant when play data has been read 
out from ROM/RAM card 17 according to a time-up signal supplied from timer 
circuit 50 until the next time-up signal is supplied from timer circuit 50 
to AND gate A8, even if coincidence signal is supplied from coincidence 
circuits 49 through AND gates A7 to flip-flop F7, no address increment 
signal is supplied through AND gates A8 and A2 to address control circuit 
46. This is made so in order that no address increment signal is supplied 
to address control circuit 46 even if trigger strings 4 are picked several 
times in the correctly operated state. 
An automatic play mode signal to AND gate A9 is also supplied as an enable 
signal when mode switch 13 is set to the playback mode (i.e., automatic 
play mode). Thus, in the automatic play mode, the reading of the next play 
data is done automatically every time when the time interval has passed, 
and automatic play is obtained in this way. 
The play data read out from ROM/RAM card 17 is once set in read buffer 
memory 47, and the note code in the play data is subsequently supplied to 
LCD section 8, on which the chord name or note name is displayed. 
FIG. 7B shows the contents of play data stored in ROM/RAM card 17. As has 
been noted, the data consists of note (chord) code, tone length code and 
picking data. The note code expresses the name of a chord, e.g., Am, 
C.sub.7, etc. or the pitch of a pure tone, e.g., C, D, etc. The tone 
length code expresses the length of a note, e.g., a quarter note, an 
eighth-note, etc. The picking data expresses the contents of picking, 
e.g., up-picking, down-picking and alternate picking. No note code is 
stored in the last address of ROM/RAM card 17, and only alternate picking 
data is stored. This data is read out as metronome data when the metronome 
mode is set. 
CONSTITUTION OF FRET LED SECTION 34 
FIG. 8A shows the construction of fret LED section 34. Navigation fret 
codes (A) to (F) for individual strings read out from fret code generation 
circuit 34 are converted into 4-bit data for driving fret LEDs 10 
corresponding to the open string fret position to the 15th fret position 
by six decoders 51. The converted data is inverted by inverters Il to I6, 
and inverted data is supplied to the cathode side of 15 fret LEDs 10 for 
each of six fret strings 3. Thus, a first fret LED 10 in the first row is 
turned on if the fret code is "0001", and a 14-th fret LED 10 is turned on 
if the fret code is "1110". Timing pulse signals t1 to t6 provided from 
CPU 37 and shifted in timing from one another, as shown in FIG. 8B, are 
supplied to the anode side of six fret LEDs 10 provided for respective six 
fret strings 3. According to these timing pulse signals t1 to t6, time 
division display process is executed for each string. 
CONSTITUTION OF TRIGGER LED CONTROL SECTION 35 
FIG. 9A shows the construction of trigger LED control section 35. The 
string code in the note code read out from ROM/RAM card section 33 is once 
latched in latch 52 to be decoded into 6-bit data for respective six 
trigger strings 4. The individual bit data are selectively supplied to 
trigger LEDs 12 through OR gates 02 to 07, so that corresponding LEDs are 
turned on. In the case when string code representing an arpeggio is read 
out, corresponding trigger LEDs 12 are turned on through this time in the 
order representing the arpeggio. 
DOWN-PICKING DISPLAY 
When the picking data read out from ROM/RAM card section 33 is down-picking 
data, the picking data is supplied as an enable signal through AND gates 
A10 and All and OR gates 09 to 014 to AND gates A12 to A17. In 
consequence, a closed loop type six-stage circulation type counter is 
formed with AND gates A10 and All, OR gate 08 and D-type flip-flops F8 to 
F13. Thus, as shown in FIG. 9B, trigger LEDs 12 are successively turned on 
from one corresponding to the first trigger string 4 to one corresponding 
to the sixth trigger string 4, and the display of down-picking play is 
done with the turning-on of trigger LEDs 12. 
ALTERNATE PICKING DISPLAY 
In the case of alternate picking data where down and up-picking data 
repeatedly occur alternately, the picking data is supplied as an enable 
signal from latch 52 through OR gates 09 to 014 to AND gates A12 to A17 
and AND gates A18 to A25. A closed loop type 12-stage circulation type 
counter is formed with AND gate A18, D-type flip-flops F14 to F19, AND 
gate A19, OR gate 08 and flip-flops F8 to F13. The Q output of flip-flops 
F8 to F13 is supplied through AND gates A12 to A17 and OR gates 02 to 07 
to trigger LEDs 12. Thus, the downward direction is first displayed with 
the turning-on of trigger LEDs 12. The Q output of flip-flops F14 to F19 
is supplied through AND gates A20 to A25 and OR gates 02 to 07 to trigger 
LEDs 12. Thus, the upward direction is displayed with the turning-on of 
trigger LEDs 12. As a result, the downward and upward directions are 
alternately repeatedly displayed. In this way alternate picking is 
displayed. 
METRONOME DISPLAY (TEMPO DISPLAY) 
When mode switch 13 is set to the metronome mode, the alternate picking 
data is repeatedly read out from ROM/RAM card 17. Thus, six trigger LEDs 
12 are displayed reciprocally according to alternate picking data. Thus, 
play tempo is displayed with reciprocal turning-on of trigger LEDs 12. 
The speed of the play tempo can be freely set by manipulating tempo knob 
15. 
More specifically, CPU 37 sets tempo data corresponding to the setting of 
tempo knob 15 in latch 52 and supplies it to frequency division circuit 
53. Thus, the frequency division of the master clock signal from CPU 37 is 
determined by frequency division circuit 53. The frequency divided clock 
signal is provided as shift clock signal to D-type flip-flops F8 to F19. 
The speed of picking play corresponds to the tempo. For this reason, 
trigger LEDs 12 are turned on successively according to the shift clock 
signal output timing. Thus, the speed of the picking tempo corresponds to 
the tempo. 
UP-PICKING DISPLAY 
The basic construction of the up-picking display is not shown in this 
embodiment. In order to display the up-picking, flip-flops F14 to F19 may 
have the same construction as and be of the opposite polarity to 
flip-flops F8 to F13. In this case, at the time of the alternate picking, 
flip-flops F14 to F19 and flip-flops F8 to F13 may arranged in a single 
closed loop. 
CONSTRUCTION OF REAL TIME RECORDING SECTION 32 
FIG. 10 is a specific construction of real time recording section 32. 
Trigger signal Ts and fret code Fc provided for each string from input 
section 31 are supplied to coincidence circuits 54 provided for respective 
strings in real time, and also are also latched in latches 55 before being 
supplied to coincidence circuits 54. Each coincidence circuit 54 effects a 
real time check as to whether the contents of the play data provided from 
input section 31, i.e., trigger signal Ts, fret code Fc, and contents of 
play data provided previously from latches 55, i.e., trigger signal Ts and 
fret code Fc, coincide. If the check proves that the two contents coincide 
without any previous change, coincidence circuits 54 provide a coincidence 
signal (high level signal) after inversion through inverters I7 to I12. 
When the current play data is different from the preceding play data, 
e.g., when the fingering position is changed from a fret position at which 
strings have previously been depressed to a different fret position, or 
trigger strings 4 are newly picked, coincidence circuits 54 provide a 
non-coincidence signal (i.e., low level signal) after being inverted 
through inverters I7 to I12. The inverted output signal is supplied as a 
latch signal to latches 55, and is also supplied as take-in signal to 
read/write control circuit 56. With this take-in signal, the trigger 
signal Ts and fret code Fc representing the contents of the play data of 
this time are supplied as note code to read/write control circuit 56. 
The time interval (t) from the time instant of a change in the contents of 
the play data (i.e., trigger signal Ts and fret code Fc) of the previous 
time till the time instant of a change in the contents of the play data 
(i.e., trigger signal Ts and fret code Fc) of this time, is counted by 
clock circuit 57. The count is supplied as tone length code Tc to 
read/write control circuit 56. When there is no change in the fret code Fc 
and when the trigger signal Ts is turned on or off, this trigger signal Ts 
and fret code Fc at this time are supplied to control circuit 56. 
Therefore, not only tone length data but also rest data is supplied. The 
note code and time interval code are supplied to writing data generation 
circuit 58. The note code and tone length code supplied to writing data 
generation circuit 58 are written in a predetermined sequence on ROM/RAM 
card 17 of ROM/RAM card section 33. The note code and tone length code are 
supplied for generating musical sounds at the time of the playback mode 
and for navigation display during the navigation mode. When the first to 
sixth strings are picked in a shorter period of time than a predetermined 
period of time in the absence of a change in fret position, this picking 
operation is judged to be an operation for chord picking. In this case, 
whether the picking is down-picking, up-picking or alternate picking is 
judged in accordance with which string direction the individual fret 
strings 4 have been picked from. The individual picking data are supplied 
to ROM/RAM card section 33 to be written in a predetermined order in 
ROM/RAM card 17. 
In this case, write address data is supplied from read/write control 
circuit 56 to address control section 46 of ROM/RAM card section 33. 
OPERATION OF EMBODIMENT 
Now, the operation of the embodiment will be described. 
A. When the Recording Mode is Set 
When mode switch 13 is set to the recording mode, the write address of 
address control section 46 is reset to "0" (first write position) by CPU 
37. Now, strings are depressed on fingerboard la at a desired fret 
position. Then, a corresponding pitch designation switch PSW is turned on. 
Then, corresponding trigger strings 4 are picked to turn on trigger 
switches TSW. As a result, the "on" signal of the pitch designation switch 
PSW is scanned by key scan circuit 40 to find the fret position, at which 
the pitch designation switch PSW is turned on. The "on" signal is rendered 
to be fret code Fc in a 4-bit digital form for each string by key code 
generation circuit 36. The "on" signal of trigger switch TSW is supplied 
as trigger signal Ts through flip-flops Fl to F6 to read/write control 
circuit 56. Every time there is a change in fret code Fc and trigger 
signal Ts, fret code and trigger signal Ts are supplied to read/write 
control circuit 56 according to a take-out signal from coincidence 
circuits 54. With this fret code Fc and trigger signal Ts the note code is 
generated to be written into ROM/RAM card 17 of ROM/RAM card section 33 
through write data generation circuit 58. At this time, the time period t 
from the instant of a change in the fret code Fc and trigger signal Ts 
till the next instant of a change is counted by clock circuit 57. This 
time t is written as tone length code through a write data generation 
circuit 58 to ROM/RAM card 17 of ROM/RAM card section 33. 
Thus, the parameters of an actual performance can be stored in real time in 
ROM/RAM card 17 in the form of note codes and tone length codes. 
When trigger strings 4 are picked substantially simultaneously, the picking 
time difference between adjacent trigger strings 4 is reduced, and the 
tone length of each sound is extremely short. When the tone length is 
shorter than the preliminarily stored predetermined picking time, it is 
supplied as picking data to ROM/RAM card 17 to be written in card 17. In 
this case, a check as to whether the picking is uppicking, down-picking or 
alternate picking is done on the basis of the trigger signal, i.e., in 
which direction trigger strings 4 have been picked. 
B. When the Navigation Mode is Set 
a. Display of Fret Operation Position 
It is assumed that play data of one musical piece is stored in ROM/RAM card 
17. The play data includes what has been stored in real time in the 
recording mode. In this case, the read address of address control section 
46 is reset to "0" by CPU 37, and the note code at the first address in 
ROM/RAM card 17 is provided through read buffer memory 47 and fret code 
generation circuit 48. Of the note code only the fret code is generated 
from fret code generation circuit 48. The fret code is supplied to each 
coincidence circuit 49 corresponding to the string code in the note code 
and is also supplied through decoder 51 in fret LED section 34 to fret 
LEDs 10. Consequently, fret LEDs 10 corresponding to fret positions to be 
fingered on fingerboard la are turned on. With the turning-on of fret LEDs 
10 the fret positions to be fingered on the fingerboard la are displayed. 
In this way, the fret position to be fingered during the performance can be 
determined visually. 
When strings are fingered at the correct fret position visually shown by 
the turning-on of fret LEDs 10, the fret code is supplied to coincidence 
circuits 49. When a coincidence signal is supplied from coincidence 
circuit 49 to flip-flop F7, an address increment signal is supplied to 
address control section 46 provided that a time-up signal has been 
provided from a timer circuit 50. According to the address increment 
signal, the next play data is read out for navigation display as noted 
above, and coincidence of the play contents read out from ROM/RAM card 17 
and play contents supplied from input section 31 is checked. 
b. Alternate Picking Display 
Now, mode switch 13 is set to the picking mode. As a result, the read 
address of address control section 46 is set to "0" by CPU 37. The picking 
data at the first address of ROM/RAM card 17 is set in latch 52 of trigger 
LED control section 35. In this case, if the contents of the picking data 
in ROM/RAM card 17 are as shown in FIG. 7B, the picking data at the first 
address is alternate picking data, so that AND gates A12 to A25 are 
enabled. As a result, a closed loop is formed with flip-flops F8 to F19, 
so that a 12-stage circulation type counter is formed. Thus, a "1" signal 
is shifted through flip-flops F8 to F19 at the frequency of a frequency 
division clock signal corresponding to a preset tempo data provided from 
frequency division circuit 53. 
While the "1" signal is being shifted from flip-flop F8 toward flip-flop 
F13, a "1" signal is supplied through AND gates A12 to A17 to trigger LEDs 
12. Thus, trigger LEDs 12 corresponding to the respective first to sixth 
strings are progressively turned on in the mentioned order, whereby the 
direction of down-picking is displayed. While the "1" signal is being 
shifted from flip-flop F14 toward flip-flop F19, a "1" signal is supplied 
through AND gates A20 to A25 to trigger LEDs 12. Thus, trigger LEDs of 
FIG. 3 12 are progressively turned on from one corresponding to the sixth 
string to one corresponding to the first string. In this way, the 
up-picking direction is displayed. Consequently, the display of the 
alternate picking can be realized with the turning-on of flip-flops F8 to 
F19. 
c. Down-Picking Display 
The third picking data shown in FIG. 7B is down picking data. When this 
down-picking data is read out from ROM/RAM card 17 and set in latch 52 of 
trigger LED control section of FIG. 4 35, AND gates A10 to A17 are 
disabled this time. As a result, a closed loop is formed with flip-flops 
F8 to F13, and a 6-stage circulation counter is formed. This, the "1" 
signal is shifted progressively from flip-flop F8 to flip-flop F18 at a 
speed corresponding to a preset tempo. Thus, trigger LEDs 12 are turned on 
progressively from one corresponding to the first string to one 
corresponding to the sixth string. 
It is to be understood that when picking trigger strings 4, the 
down-picking can be done smoothly and reliably by observing the direction 
in which trigger LEDs 12 are turned on progressively. 
d. Metronome Display (Tempo Display) 
When mode switch 13 is set to the metronome mode, the read address of 
address control section 46 is set to the last address by CPU 37. As the 
last address of ROM/RAM card 17, neither note code nor tone length code is 
stored, but only alternate picking data is stored. When the alternate 
picking data is read out, it is latched from ROM/RAM card 17 to latch 52 
in trigger LED control section 35. Thus, like the case of the picking mode 
a 12-stage circulation counter is formed with flip-flops F8 to F19. Thus, 
a "1" signal is shifted through flip-flops F9 to F19 at a speed 
corresponding to the preset tempo. As a result, trigger LEDs 12 are 
shifted in alternate upward and downward directions. 
The speed of progressive turning-on of trigger LEDs 12 is based on 
frequency of the frequency division clock signal from frequency division 
circuit 53, while the frequency division ratio of frequency division 
circuit 53 is based on the preset tempo of the tempo knob 15 so that is 
corresponds to the tempo. Thus, by changing the preset tempo of the tempo 
knob 15, the speed of progressive turning-on of trigger LEDs 12 is 
changed. 
Thus, it is possible to show the tempo using trigger LEDs 12 indicating the 
picking direction. For this reason, trigger LEDs 12 may be used to fulfill 
the metronome function. 
MODIFICATION 
In this embodiment, LEDs 10 and 12 are used as operation content display 
means and are provided in fingerboard 1a and body 2. However, this 
embodiment is by no means limitative. A different example is shown in FIG. 
11. In this case, photoconductive members 10a containing a fluorescent 
material are formed in fret string 3, and light from each LED 10 is lead 
from one end of each photoconductive member 10a to be emitted only from a 
tapered surface 10b provided at the other end of the photoconductive 
member 10a. Reference numeral 10c designates a cylindrical shield, and 
reference numeral 10d transparent cap accommodating fret string 3 and each 
photoconductive member 10a. In this construction, the position, at which 
fret string 3 is to be depressed, can be confirmed by observing the state 
of the taper surface 10b of the photoconductive member 10a. Thus, it is 
possible to operate strings more speedily and reliably. Further, the LEDs 
may be replaced with any other display elements capable of visual display, 
e.g., liquid crystal display elements, lamps, etc. Further, display 
elements may be provided in any other place as well as those noted above 
so long as fret positions to be depressed and the operating direction can 
be visually determined. 
In the above embodiment, the pitch data designation means consists of pitch 
designation switches PSW of a switching type, but it is also possible to 
use a resistance detection system (as disclosed in U.S. patent 
specification No. 4,235,141) or a system based on contact between a 
conductive string to which current is supplied and a conductive fret piece 
(as disclosed in U.S. patent specification 4,658,690). Further, as the 
operated string data input means, in addition to string trigger switches 
TSW of switching type as in this embodiment, a system using hole elements 
and magnets (as disclosed in U.S. patent specification 4,658,690 noted 
above), a touch switch system (as disclosed in U.S. patent specifications 
Nos. 4,336,734, 4,339,979, 4,248,128 and 4,078,464) and a system for 
blocking laser beam may be used. Further, the invention is also applicable 
to a guiter synthesizer (e.g., U.S. patent specification No. 4,606,255), 
in which a plurality of strings are provided, predetermined fret fingering 
positions are provided for each string, and when string picking operation 
is effected along with the fret fingering operation, musical sounds of 
pitches designated by the fret fingering operation are generated in 
response to the string picking operation. 
Further, in this embodiment the play data memory means may be built-in ROMs 
or RAMS or magnetic tapes, magnetic disks or optical disks. Further, the 
picking data may include arpeggio data. Further, the invention is 
applicable to violins and cellos as well as guitars. Further, the above 
embodiment is by no means limitative, and various means and names are also 
not limitative.