Music – Instruments – Electrical musical tone generation
Reexamination Certificate
2002-09-24
2004-06-22
Fletcher, Marlon (Department: 2837)
Music
Instruments
Electrical musical tone generation
C084S737000, C084S104000
Reexamination Certificate
active
06753467
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an electronic musical instrument and, more particularly, to an electronic musical instrument such as an electronic percussion instrument, a player's console on which a musician performs for producing electric signals and a signal processing system for producing an audio signal representative of the music sound.
DESCRIPTION OF THE RELATED ART
Various sorts of electronic percussion instrument have been proposed and sold in the market. An electronic drum is a typical example of the electronic percussion instruments, and largely comprises a rim, a head, a head sensor and a rim sensor. The head is stretched over the rim, and the head sensor and rim sensor are attached to the head and the rim, respectively. The head sensor and rim sensor convert the vibrations of the head and the vibrations of the rim to respective electric signals, and beat sound and rim shot sound are independently produced on the basis of the electric signals.
A typical example of the electronic drum is disclosed in Japanese Patent Application laid-open No. hei 6-175651. The prior art electronic drum disclosed in the Japanese Patent Application laid-open comprises a saucer-shaped drum body made of hard rubber, a pad plate supported by the saucer-shaped drum body through cushions, a pad rubber stretched over the front surface of the pad plate, a semi-circular rim plate fixed to the periphery of the saucer-shaped drum body and two sensors. The two sensors are implemented by piezoelectric transducers. One of the piezoelectric transducers is attached to the reverse surface of the pad plate, and the other piezoelectric transducer is attached to the inner surface of the semi-circular rim plate. A lead cable is connected to the piezoelectric transducer attached to the pad plate, and another lead cable is connected to the other piezoelectric transducer attached to the rim plate.
While a drummer is beating the pad rubber with sticks, the pad plate vibrates, and the vibrations of the pad plate are converted through the piezoelectric transducer to an electric signal. When the drummer gives rim shots to the rim plate, vibrations are propagated through the rim plate to the piezoelectric transducer, and the vibrations are converted to another electric signal. The electric signals are independently propagated through the lead cables to a signal processing system. Drum sound and rim shot sound are produced on the basis of the electric signals through a signal processing in the signal processing system. Thus, the prior art electronic drum requires two sensors and two lead cables for propagating the electric signals from the two sensors to the signal processing system.
Another prior art electronic drum has a single film switch and a piezoelectric transducer. The vibrations are converted through the piezoelectric transducer to an electric signal, and the electric signal is propagated through a lead cable to a signal processing system. The film switch is also connected through a lead cable to the signal processing system. When the film switch is depressed, an electric signal is supplied from the film switch through another lead cable to the signal processing system. The signal processing system is responsive to the electric signal supplied from the film switch so as to determine the timbre of drum sound. When the film switch is opened, the signal processing system gives one of the two envelops to the electric signal representative of the drum sound, and the drum sound is produced at a timbre corresponding to the given envelope. On the other hand, when the film switch is closed, the signal processing unit gives the other envelope to the electric signal, and the drum sound is produced at another timbre. Thus, the prior art electronic drum also requires two sensors and two lead cables.
FIG. 1
shows a typical example of the signal processing system available for an electronic drum. The prior art electronic drum is broken down into a head unit
100
, a signal processing unit
200
and a stereocable
300
. The separate-type electronic drum is preferable, because the signal processing unit
200
is free from the beats on the head unit
100
.
The contour of the head unit
100
is shown in
FIGS. 2A and 2B
. The electronic drum is corresponding to a snare drum. The head unit
100
includes a rim
102
and a head
104
. The rim
102
has a ring shape, and the head
104
is stretched over the rim
102
. The head unit
100
further includes a piezoelectric transducer
110
and a rim-shot switch
120
, which are provided in association with the head
104
and the rim
102
, respectively. The piezoelectric transducer
110
is connected between a signal terminal
112
and a ground terminal
114
, and the rim-shot switch
120
is connected between another signal terminal
116
and the ground terminal
114
. Thus, the piezoelectric transducer
110
and the rim-shot switch
120
are arranged in parallel in the electronic drum
100
.
The piezoelectric transducer
110
converts vibrations of the head
104
to an electric signal, the waveform of which is representative of the vibrations. The electric signal is supplied from the signal terminal
112
to the signal processing system
200
. On the other hand, the rim-shot switch
120
is implemented by a normally-off type switch. When a drummer gives a rim shot to the rim
102
, the rim-short switch
120
turns off, and changes the potential level at the signal terminal
116
to the ground. The potential level at the signal terminal
116
is supplied to the signal processing system
200
as a detecting signal.
The prior art signal processing system
200
includes an envelope extractor
210
, a Schmitt trigger-inverter circuit
220
, a central processing unit
230
, an analog-to-digital converter
231
, two signal terminals
232
/
234
and a ground terminal
236
. The Schmitt trigger-inverter circuit
220
has the threshold of the order of 0.6 volt. The signal terminal
232
is connected to an input node of the Schmitt trigger-inverter circuit
220
, and is further connected to a power supply line
238
through a resistor element
240
. The output node of the Schmitt trigger-inverter circuit
220
is connected to a signal port of the central processing unit
230
. The other signal terminal
234
is connected to an input node of the envelope extractor
210
, and the ground terminal
236
is grounded. Thus, the signal terminals
232
/
234
and the ground terminal
236
are connected in parallel through the stereocable
300
to the signal terminals
116
/
112
and the ground terminal
114
, and the three conductive lines are incorporated in the stereocable
300
. The positive potential is supplied from the power supply line
238
through the resistor element
240
to the signal terminal
232
, which in turn supplies the positive potential through the stereocable
300
to the signal terminal
116
. The output node of the envelope extractor
210
is connected through the analog-to-digital converter
231
to the signal port of the central processing unit
230
.
The envelope extractor
210
is a combined circuit of amplifier, rectifier and integrator. While a drummer is beating the head
104
, the piezoelectric transducer
110
generates the electric signal representative of the vibrations of the head
104
, and the electric signal is supplied from the piezoelectric transducer
110
through the stereocable
300
to the input node of the envelope extractor
210
. The envelope extractor
210
amplifies and rectifies the electric signal, and integrates the rectified electric signal for generating an envelope signal representative of the envelope of the waveform. The envelope extractor
210
supplies the envelope signal to the analog-to-digital converter
231
, and the analog-to-digital converter
231
converts discrete values of the envelope signal to corresponding binary codes. The series of binary codes is representative of the envelope of the waveform, and is fetched by the central processing unit
230
for producing music data codes representative of drum so
Harada Minoru
Tanaka So
Fletcher Marlon
Yamaha Corporation
LandOfFree
Simple electronic musical instrument, player's console... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Simple electronic musical instrument, player's console..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Simple electronic musical instrument, player's console... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3365269