Abstract:
In this thesis the frequency modulation for different types of modulating circuits was studied and
a low-powered, cost-effective modulator was developed. By changing the wave's instantaneous
frequency, information is encoded in a carrier wave using frequency modulation. The technology
is utilized in computing, signal processing, radio broadcasting, navigation and
telecommunications. Three modulating circuits were designed and developed for the study. The
performance of Triangular Modulating Circuit, Sawtooth Modulating Circuit and Sinusoidal
Modulating Circuit was studied and analyzed in terms of message transmission. To validate the
proposed modulating circuit, its performance was compared with MATLAB script, Simulink
model and Python script. Its performance was also compared with the modulation done by existing
model “EMONA Telecoms- Trainer 101” present at Electrical, Electronic and Communication
Engineering lab of MIST. Results of the analysis show that if the modulation is linear, the
frequency change is directly proportional to the modulating voltage's amplitude. Parameters of the
modulated signal when used in MATLAB, Python and Simulink gave the same modulated signals
that validates the modulation done by the proposed circuits. The proposed modulating circuits
generate signal with very less noise at the desired voltage level which also matches the
performance capacity of microwave VCOs. And so, it can be used effectively to develop a low
cost FMCW Radar. The proposed modulating circuits can be used in telemetry, video broadcasting
and recording, sound synthesis, medicine, navigation, aviation, radar, analog and digital data
transmission and many other fields to a further extent
