MC3456

7

MOTOROLA ANALOG IC DEVICE DATA

APPLICATIONS INFORMATION

Tone Burst Generator

For a tone burst generator, the first timer is used as a

monostable and determines the tone duration when triggered

by a positive pulse at Pin 6. The second timer is enabled by

the high output of the monostable. It is connected as an

astable and determines the frequency of the tone.

Dual Astable Multivibrator

This dual astable multivibrator provides versatility not

available with single timer circuits. The duty cycle can be

adjusted from 5% to 95%. The two outputs provide two phase

clock signals often required in digital systems. It can also be

inhibited by use of either reset terminal.

(RA + 2RB) C

Figure 20. Tone Burst Generator

Figure 21. Dual Astable Multivibrator

RT

Trigger

Trigger

Trigger

Reset

4

Discharge

Threshold

7

Gnd

1/2

MC3456

14

VCC

5

Output

10

Reset

3

9

Control

0.01

µF

Output

7

Gnd

0.01 mF

C2

14

VCC

13 Discharge

12 Threshold

8

11 Control

RB

RA

+ 15 V

Gnd

C1–

R1

C1

Reset

2

Discharge

1

4

14

10 k

5

1N914

1N914

10 k

9

Output

Trigger

10

Reset

+15 V

R2

Threshold

12

13

Discharge

C2

Gnd

11

Control

Voltage

0.001

8

Output

0.001

Output

6

37

Gnd

f =

0.91

(R1 + R2) C

for C1 = C2

Duty Cycle

R2

R1 + R2

t = 1.1 RT C1

f =

1.44

Control

Voltage

Threshold

Trigger

1/2

MC3456

1/2

MC3456

1/2

MC3456

6

1

2