SOURCEFORGE » RALF » 2015 Quantitative analysis of RF signals

h1. Report

h2. Introduction

Satellites are a quite new and growing way to improve different ways to communicate all over the world. In order to establish this communication, signals must be transmitted between a satellite and the ground station. To be readable on the two ways, these signals must comply some specifications and to check that this is the case, we can use for example a signal analyser.

Signal analyser

Assess quality of signals

Figure of merit, characteristics

h2. Scope and objectives

Labview

ni-USRP 2950 R : characteristics, block diagram

Antenna : Ku band, X-band ?

Satellites to target

Measurements to carry out : Analogic vs digital

h2. Implementation

h3. Definition of inputs and ways to compute the outputs

h3. Simulation

First we decided to design our signal analyser and to test it with simulated signals generated automatically such as sine wave.

To do this we first created a VI able to generate a noisy signal. This signal correspond to the addition of three basic signals and a white Gaussian noise. For each basic signal we can set the signal type, the frequency, the amplitude and the offset. For the noise, we can set the noise standard deviation.

Consequently we can insert the noisy signal into our signal analyser to test it. 

For example if we set 3 sine waves with different frequencies and amplitudes we observe this spectrum <warning>mettre photo</warning>

We can also observe the spectrum of a noisy sine wave <warning>mettre photo</warning>

In the two cases, the spectrum match with the expected values (frequencies and amplitudes)

h3. Moving from simulation to acquisition of real signals

When he tried to replace the 

Definition of inputs and computation models of the outputs

Simulation

Generation of a noisy signal + analogic and digital measurements ⇒ do the results match what is expected ?

Expected issues when we move to the acquisition of the real signal ?

h2. Tests and results

Explanation of the commands and operations to reach the presented results + comparison between what is display by the signal analyser and by Labview + explanations