Energy efficient asynchronous multiuser ultra-broadband transmitter in technology CMOS

Cilj je ovog rada razvoj višekorisnickog energetski ucinkovitog predajnog sustava kako bi se postigao bežicni prijenos analogne informacije na kratke udaljenosti koristeci pritom ultraširokopojasne radio impulse kao nositelje informacije. Predajni sustav cine modulator temeljen na sklopovima za vremensko kodiranje informacije i generator ultra-širokopojasnih radio impulsa. Sklop za vremensko kodiranje informacije izveden je integralnim impulsno frekvencijskim modulatorom (IPFM) kojim se moduliraju analogne velicine (napon, struja) u niz unipolarnih impulsa na nacin da je vremenski interval izmeu susjednih impulsa funkcija analognog, modulacijskog signala. Svojstvo višekorisnickog pristupa postiže se kodiranjem svakog korisnika koji šalje informacije u istom komunikacijskom kanalu jedinstvenom celijom za kašnjenje, cija vrijednost kašnjenja IPFM signala kodira korisnika koji šalje informaciju. Na navedeni nacin, modulator generira niz impulsa ciji meusobni razmak kodira informaciju dok je u širini impulsa kodiran korisnik koji šalje navedenu informaciju. Izostankom generatora takta modulatora i mikroupravljaca postiže se njegova energetska ucinkovitost. Impulsni niz s izlaza modulatora dovodi se na generator ultra-širokopojasnih radio impulsa koji generira ultra-širokopojasni impuls za svaki ulazni i silazni brid navedenog impulsnog niza. S obzirom na svojstvo kratkog intervala trajanja ultra-širokopojasnog impulsa, istima se postiže svojstvo malog iznosa energije po impulsu. S ciljem miniturizacije sklopa kao i postizanja vece energetske ucinkovitosti predajnog sustava, isti je implementiran u CMOS integrirani krug. U sklopu rada ukupno su razvijena dva generatora ultra-širokopojasnih impulsa. Prvi se temelji na oblikovanju bridova pravokutnog signala, dok se drugi temelji na križno prospojenom LC oscilatoru s ugraenim sklopom za upravljanje kojim se automatski kontrolira njegovo uklapanje i isklapanje s obzirom na struju oscilatora, temperaturu okoline integriranog kruga kao i utjecaj kvantnog šuma i šuma sacme na pocetak oscilacija. Kako bi se izmjerio utjecaj višekorisnickog pristupa na pogrešku u prijemu simbola, IPFM modulator i demodulator implementirani su u FPGA, gdje se emuliranjem primopredajnog sustava promatra utjecaj parametara modulacije na omjer pogrešno zaprimljenih simbola. Temeljem dobivenih rezultata, provedena su mjerenja nad ukupno cetirima IPFM predajnicima koji asinkrono i kontinuirano šalju informaciju unutar istog komunikacijskog kanala. Za potrebe istog, u CMOS tehnologiji izraen je detektor ultra-širokopojasnih impulsa kojim se iste pretvara u unipolarne s ciljem njihove jednobitovne digitalizacije, dekodiranja i, naposljetku demodulacije signala od navedenog korisnika. Rad je rezultirao s ukupno cetirima znanstvenim doprinosima a to su: 108 1. Izrada višekorisnickog ultra-širokopojasnog predajnika temeljenog na integralnom impulsno frekvencijskom modulatoru i kodiranju korisnika jedinstvenim celijama za kašnjenje u tehnologiji CMOS. 2. Vrednovanje znacajki impulsno integralnog frekvencijskog modulatora u tehnologiji CMOS. 3. Izrada sustava za procjenu ucestalosti pogreške simbola dekodiranih impulsnih nizova odaslanih s višestrukih višekorisnickih integralnih impulsno frekvencijskih modulatora temeljenih na kodiranju korisnika jedinstvenim celijama za kašnjenje. 4. Izrada ultra-širokopojasnog generatora impulsa s promjenjivom spektralnom gustocom snage temeljenog na LC oscilatoru u tehnologiji CMOS. The aim of this thesis is to develop a multi-user energy efficient transmission system in order to achieve wireless transmission of analog data over short distances using ultra-wideband radio pulses as data carriers. The transmission system consists of a modulator based on circuits with time data coding and an ultra-wideband radio pulse generator. The circuits with time data coding are made of an Integral Impulse Frequency Modulator (IPFM) which modulates an analog quantity (voltage, current) into a series of unipolar pulses in such a way that the time interval between adjacent pulses is a function of the analog modulation signal. The multiuser approach feature is achieved by encoding each user who sends data in the same communication channel with a unique delay cell whose IPFM signal delay value encodes the user sending the data. In this way, the modulator generates a series of pulses whose spacing encodes the data while the pulse width encodes the user sending the aforementioned data. The absence of a clock modulator generator and a microcontroller achieves its energy efficiency. A pulse array from the output of the modulator is fed to an ultra-wideband radio pulse generator that generates an ultra-wideband pulse for each input and output edge of the pulse array. Given the short duration of the interval of the ultra-wideband pulse, they achieve the property of a small amount of energy per pulse. With the aim of miniaturizing the circuit as well as achieving greater energy efficiency of the transmission system, it has been implemented in the CMOS integrated circuit. As part of the paper, a total of two ultra-wideband pulse generators were developed. The first was based on the design of the edges of a rectangular signal, while the second was based on a cross-connected LC oscillator with a built-in control that automatically controls the on and off switch with respect to the oscillator current, integrated circuit ambient temperature, and the influence of quantum noise and shot noise to the beginning of the oscillation. To measure the impact of multi-user access on symbol reception error, the IPFM modulator and demodulator were implemented in the FPGA, where the effect of modulation parameters on the ratio of incorrectly received symbols was observed by emulating the transceiver system. Based on the obtained results, measurements were performed on a total of four IPFM transmitters that sent data asynchronously and continuously within the same communication channel. For the same requirement in the CMOS technology, a detector of ultra-wideband pulses was made, which converted these impulses into unipolar ones with the aim of their one-bit digitization, decoding, and, finally, demodulation of the signal from the specified user. 110 The paper resulted in a total of four scientific contributions: 1. Development of a multi-user ultra-wideband transmitter based on an integral pulse frequency modulator and user coding with unique delay cells in CMOS technology. 2. Evaluation of pulse frequency modulator features in CMOS technology. 3. Development of a system for estimating the error rate of decoded pulse array symbols transmitted from multiple multi-user integral pulse frequency modulators based on coding users with unique delay cells. 4. Development of an ultra-wideband pulse generator with variable power spectral density based on an LC oscillator in CMOS technology.