DSY1501 Assignment 1 2025

DSY1501
ASSIGNMENT 1 2025

UNIQUE NO.
DUE DATE: 2025

, Question 1 [12 Marks]

1.1

In a negative-logic pulse, the trailing edge refers to the:
✅ d) Falling edge


Explanation:
In negative logic, the signal is considered active when it is low. Therefore, the trailing
edge—where the pulse ends—is the point where the signal changes from high to low,
which is known as the falling edge.

1.2

A square wave has an 'on' time of 10 ms and an 'off' time of 50 ms. What is the
duty cycle percentage?
✅ a) 16.66%


Calculation:

Duty Cycle=(TonTon + Toff)×100=(1010+50)×100=(1060)×100=16.66%\text{Duty
Cycle} = \left(\frac{\text{Ton}}{\text{Ton + Toff}}\right) \times 100 \\ = \left(\frac{10}{10 +
50}\right) \times 100 = \left(\frac{10}{60}\right) \times 100 =
16.66\%Duty Cycle=(Ton + ToffTon)×100=(10+5010)×100=(6010)×100=16.66%

1.3

Determine the frequency of a pulse where Ton = 10 ms and Toff = 20 ms:
✅ c) 33.33 Hz


Calculation:

Total Period(T)=10 ms+20 ms=30 ms=0.03 sFrequency(f)=1T=10.03=33.33 Hz\text{Tot
al Period} (T) = 10\text{ ms} + 20\text{ ms} = 30\text{ ms} = 0.03\text{ s} \\
\text{Frequency} (f) = \frac{1}{T} = \frac{1}{0.03} = 33.33\text{ Hz}Total Period(T)=10 ms