SlideShare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy.
SlideShare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our Privacy Policy and User Agreement for details.
Successfully reported this slideshow.
Activate your 14 day free trial to unlock unlimited reading.
3.
擬似ハムバッキングピックアップ
・2つのシングルコイルピックアップを逆の位相で
並列に配置した構造
弦振動によりコイルに流れる電流 : 同相
外部からの電磁結合によるノイズ : 逆相
・ギターの信号のみを倍化し,ノイズをキャンセル
する出力特性を持つ
Hum-backing pickup
Steel string
N
S
S
N
4.
Waveform of pseudo hum-backing pickup response
測定結果
Waveform of single coil pick up response
-100
-75
-50
-25
0
25
50
75
100
Voltage[mV]
876543210
Time [sec]
-300
-200
-100
0
100
200
300
Voltage[mV]
876543210
Time [sec]
64.7SNR [dB]
46.34SNR [dB]
5.
Simulation model
振動系のシミュレーションモデル
・弦の任意の位置 に永久磁石を設置
→ 吸引力
・2つの負スチフネスが作用する弦の振動方程式
・ の位置に高さ なる初期変位を与える
),(n0 taySFF mmmtm
)},(){()},(){(
),(),(
22n02211n0112
2
2
2
taySFaxtaySFax
x
txy
T
t
txy
・・①
max
Pseudo Hum-backing Pickup
8x
x
y
1a
2a
8
h
h
)2,1( m
1355.01 a
1535.02 a
6305.0
0010.0h
[m]
[m]
[m]
[m]
6.
振動周波数の解析
・特性方程式
・非調和性 Inharmonicity
)(sinsinsin)(
)(sinsinsin)(
22
2n
2
11
1n
1
a
c
a
c
S
c
cH
a
c
a
c
S
c
cH
n
1
2log1200
nf
fn
n
・・②
T
c :波速度
[cent]
)(sinsin)()()( 2
2
1
2
2
2n1n
21 a
c
a
c
SS
HHW
とおくと
7.
3135.93393135.96063135.93683135.963516
2939.93022939.94252939.95342939.965815
2743.93892743.93902743.96802743.968114
2547.94962547.96202547.95792547.970313
2351.93572351.97042351.93792351.972612
2155.91262155.94602155.94162155.974911
1959.92571959.93471959.96821959.977210
1763.96171763.96381763.97741763.97959
1567.94731567.98031567.94881567.98178
1371.88021371.94341371.92081371.98407
1175.86761175.91361175.94031175.98636
979.9486979.9533979.9838979.98865
783.9700783.9901783.9707783.99094
587.7914587.9103587.8741587.99323
391.5630391.7743391.7844391.99542
195.6103195.7848195.8242195.99771
Ideal
Partial
No.
only 2nS only andn1S
Vibration frequencies affected by 1 or 2 negative stiffness
振動周波数の算出
2nSn1S
8.
Inharmonicities affected by 1 or 2 negative stiffness
非調和性 Inharmonicity
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Inharmonicity[cent]
16151413121110987654321
Partial No.
Sn1 and Sn2
Sn1 only
Sn2 only
9.
出力のシミュレーション
・弦の変位により誘導される起電力
・エレクトリックギターで使用される第3弦のG3音を
シミュレーションの対象とする
・ハムバッキング・ピックアップの出力特性を再現
→2つの永久磁石からの出力を合成する
dt
txdy
txy
NU
Em
),(
)},({ 2
R
1
cossin),(
n
n
t
n t
xn
eAtxy n
S01
8
sin
)(7
128
2
n
n
h
An
,
,