Abstract:
Aim of the project was to develop a communication network for transmission and reception of voice and telemetry information. Initially, it was accepted as part of Pakistan National Student Satellite-1( a project initiated by SUPARCO ), but due to delay in funding instead of space/military grade components, normal off the shelf low cost components have been utilized to achieve almost the same results as envisaged through PNSS-1. We have designed and implemented a ground station transmitter and receiver unit of a satellite system. Ground station transmitter unit involves modulation, up conversion and amplification of the voice signal and its interfacing with an antenna. Signal is transmitted at a frequency of 114MHz. A prompt signal is transmitted using BPSK modulation at 415 MHZ to the telemetry side of the payload unit to start transmission with output power of 1W whereas ground station receiver unit includes two modules.
A) Demodulation of FM signal
Voice signal coming from the payload transmitter which is having a frequency of 110 MHz is down converted, demodulated and amplified and is fed to the speaker jack.
B) Demodulation of BPSK signal:
It receives the sensor data in digital form from the payload transmitter having frequency of 433MHZ. This data will include humidity of the payload, its temperature and current readings. After down conversion and demodulation of the received data it is displayed on LCD using Atmel.
