Phase Locked Loop (PLL) for Doppler Effect

Phase Locked Loop (PLL) for Doppler Effect Compensation using
M-ary FSK Modulation on 2.4Ghz LEO Satellite
Nama mahasiswa
: Rahardhita Widyatra Sudibyo
NRP
: 2211203202
Pembimbing
: Prof. Ir. Gamantyo Hendrantoro, M.Eng., Ph.D.
Dr. Ir. Suwadi, MT.
ABSTRACT
Nano Satellites is one of many research centers worked at the college level.
The purpose of the nano satellites were made due to the relatively small size and
relatively low cost. Data sent from the nano satellites can be text or image. In the
transmit process there are a few things that need to be calculate, such as modulation
techniques used and the Doppler effect when satellite crossing the ground station. In
this study using M-ary FSK modulation to reduce the influence of the Doppler effect.
Phase shift caused by the Doppler effect is also a problem on the
demodulation process. To resolve this problem in this study used the technique Phase
Locked Loop. PLL works is by repeating the process continuously to get correct
phase and frequency based on reference before trough the demodulation process.
With an altitude of 700km on a satellite has a 2.4Ghz, Doppler shift with frequency
50.5Khz and has a visible time 905 seconds. The signal result that has passed through
PLL can be restored as a signal with error percentage 2%.
Kata kunci : Nano satelit, Modulasi, MFSK, Doppler, Phase Locked Loop.
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