ASSIGNMENT #1 FEBRUARY 2021 201CDE ANALOG AND DIGITAL ELECTRONICS (ADE)
1. The objective of simulation is to verify and optimize the design.
Simulation can idealize a circuit. The objective of measurement is
to experimentally confirm the specifications. Measurements must
consider all nonidealities.
a. Describe completely the definition of the Common
Mode Rejection Ratio (CMRR) of an operational
amplifier. Recommend a circuit to measure the CMRR.
Use MULTISIM to conduct the measurements of
CMRR. Provide the plot of the CMRR (in dB) versus
Frequency (Hz) to prove the efficacy of the OPAMP.
(15 Marks)
b. What do you understand by the term “slew rate” of an
operational amplifier? Recommend a circuit to
measure this parameter and provide complete
measurement of this parameter using the MULTISIM
environment.
(15 Marks)
2. Design an operational amplifier circuit that performs the
mathematical operation of integration with respect to time; that is,
its output voltage is proportional to the input voltage integrated
over time..
(5 Marks)
a. Explain fully the operation of the circuit and derive its
input/output characteristic equation.
(10 Marks)
b. Using MULTISIM show the performance of the circuit
when the input was impressed with the following
waveforms.
i. Square Wave
ii. Triangular Wave
iii. Sine Wave
(10 Marks)
c. Show that if the input is a sine wave of varying
frequency the OPAMP integrator performs like an
active lowpass filter.
(5 Marks)
3. An oscillator is the basic element of all AC signal sources and
generates sinusoidal signals of known frequency and amplitude.
It is one of the basic and useful instruments used in electrical
and electronic measurement. Oscillators are used in many
electronics circuits and systems providing the central clock
signal that controls the sequential operation of the entire
system.
a. Describe the operation of an OPAMPbased oscillator
using the concept of a basic oscillator feedback
circuit. Your description must include all pertinent
equations relating the overall closed loop gain and
the openloop and feedback gain
(10 Marks)
b. Figure 1 shows the complete schematic diagram of a
variable frequency COLPITTS Oscillator. Use the
MULTISIM platform to simulate the operation of this
oscillator as you vary the values of the inductor, ????,
from 1???????? to 62????????. What is the gain of the oscillator?
(3 Marks)
i. Tabulate the output frequencies versus the
various inductor values.
(7 Marks)
ii. Show the output waveforms as displayed on
the oscilloscope for ten selected
frequencies.
(10 Marks)
iii. Show the output waveforms as displayed on
the spectrum analyzer of the output
amplitude versus frequency.
(10 Marks)
Figure 1: Complete schematic diagram of a COLPITTS Oscillator (Diagram in PDF)

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