Supervisors info:
ΔΙΟΝΥΣΙΟΣ Ι. ΡΕΙΣΗΣ, Καθηγητής Τμήμα Φυσικής ΕΚΠΑ,
ΕΚΤΟΡΑΣ ΝΙΣΤΑΖΑΚΗΣ, Καθηγητής Τμήμα Φυσικής ΕΚΠΑ
ΜΑΡΚΟΣ ΑΝΑΣΤΑΣΟΠΟΥΛΟΣ, Αναπληρωτής Καθηγητής Τμήμα Φυσικής ΕΚΠΑ
Summary:
The objective of this diploma thesis is the design and the construction of a broadband range (Scanner) analog communication receiver in VHF/UHF band. Receiver is capable of tuning in 47 to 860 MHz frequency range. Tuning is controlled by a phase locked loop circuit, PLL. Furthermore, it is equipped with AM/FM demodulation. At last, it has a squelch circuit and a received signal strength indicator, also known as S-meter.
At the beginning of this thesis, we present the basic theory that rules all the analog AM/FM, VHF/UHF hyperheterodyne receivers. We provide the block diagrams of AM, FM receivers and present the basic qualitative characteristics of their performance evaluation.
Next, in the second chapter, we analyze the design and construction of high and intermediate frequency stage (RF/IF) of our receiver. This stage is also known in the literature as the analog front-end stage. In the same chapter we also analyze the power supply unit, the audio frequency amplifier and the circuit for indicating the strength of the received signal (S-meter). For the final control and regulation of that stage, experimental measurements were also made with the help of scientific laboratory instruments, where and when this was necessary.
The third chapter analyzes the control and tuning circuit of the receiver. This stage is an automatic phase-locked loop circuit, PLL. After a brief historical review, we give the basic block diagram of the PLL, along with the necessary mathematical background. Next, we examine first- and second-order PLLs, as well as their qualitative characteristics. We close chapter three with the analysis of the PLL circuit of our receiver.
Finally, in the last chapter of the paper, the basic principles of DAB (Digital Audio Broadcasting) digital receivers and SDR (Software Defined Radio) technology are mentioned. The aim is to give an overview of the telecommunication systems of the future. In addition, a connection is made between the present work and the new technologies in the field of telecommunications. In fact, we come to the conclusion that even though we have moved into the digital age, high frequency analog circuits are essential.
Keywords:
Amplitude modulation (AM), Frequency modulation (FM), frequency synthesizer, phase locked loop (PLL), automatic control system, linear time invariant system (LTI), digital audio broadcasting (DAB), orthogonal frequency-division multiplexing (OFDM), software defined radio (SDR)
