36
Pulse Waveform
The pulse wave is another classic waveform with variable pulse width and contains very strong
overtones. Unlike the sawtooth wave the overtone content of the pulse wave can be altered by
changing pulse width. For example, a symmetrical pulse contains only odd overtones (3, 5, 7, …).
See the illustration below.
O
U
TP
U
T
(V
ol
ts
)
5.0
2.5
0.0
-2.5
-5.0
-7.5
3.00
4.00
5.00
6.00
7.00
8.00
Time (milliseconds)
7.5
dB
V
rm
s
0.0
-10.0
-30.0
-40.0
-50.0
-60.0
-70.0
-80.0
-90.0
1.0k
3.0k
5.0k
7.0k
9.0k
11.0k 13.0k 15.0k 17.0k 19.0k
Frequency (Hz)
440.00 Hz
OSCILLATOR OUTPUT, SQR(50%), A440
-20.0
A pulse wave with 26% (or 74%) pulse width contains the following overtones; 2, 3, 5, 6, 7, 9, 10,
11,…). See the illustration below.
A pulse wave with 33% (or 67%) pulse width contains the following overtones; 2, 4, 5, 7, 8, 11,…).
See the illustration below.
O
U
TP
U
T
(V
ol
ts
)
5.0
2.5
0.0
-2.5
-5.0
-7.5
3.00
4.00
5.00
6.00
7.00
8.00
Time (milliseconds)
7.5
1.0k
3.0k
5.0k
7.0k
9.0k
11.0k 13.0k 15.0k 17.0k 19.0k
Frequency (Hz)
OSCILLATOR OUTPUT, FILTERED PULSE(26%), A440
dB
V
rm
s
0.0
-10.0
-30.0
-40.0
-50.0
-60.0
-70.0
-80.0
-90.0
440.00 Hz
-20.0
O
U
TP
U
T
(V
ol
ts
)
5.0
2.5
0.0
-2.5
-5.0
-7.5
3.00
4.00
5.00
6.00
7.00
8.00
Time (milliseconds)
7.5
dB
V
rm
s
-10.0
-30.0
-40.0
-50.0
-60.0
-70.0
-80.0
-90.0
1.0k
3.0k
5.0k
7.0k
9.0k
11.0k 13.0k 15.0k 17.0k 19.0k
Frequency (Hz)
440.00 Hz
OSCILLATOR OUTPUT, PULSE(33%), A440
-20.0
0.0
