KoREMA - Croatian Society for Communications, Computing, Electronics, Measurement and Control
Abstract
In this paper the Asymmetric Digital Subscriber Line (ADSL) analog front end (AFE) designs are described and compared. AFE is the part of ADSL modems most responsible for quality signal transmission over phone wires. It can be divided into the transmitting path (TX) circuitry, the receiving path (RX) circuitry and the hybrid network and transformer. The operations and realizations of each functional block are presented. There are the D/A converter, the filter and the line driver in the TX path and the voltage gain amplifier, the filter and the A/D converter in the RX path. The hybrid network and transformer process signals in both directions. Different fabrication technologies are used for the practical realizations of the AFE chip. The directions of the further developing are notified.U radu su opisane i uspoređene izvedbe ADSL analognog sučelja. Analogno sučelje kao dio ADSL modema najodgovornije je za kvalitetan prijenos signala preko telefonskih žica. Može se podijeliti u sklopove predajnog puta, prijamnog puta i hibridnu mrežu s transformatorom. Prikazan je rad i izvedbe svakog funkcijskog bloka. To su D/A pretvornik, filtar i izlazno pojačalo u predajnom putu te ulazno pojačalo, filtar i A/D pretvornik u prijamnom putu. Hibridna mreža i transformator prosljeđuju signale u oba smjera. Za praktičnu izvedbu AFE čipa koriste se razne tehnologije. Naznačene su smjernice daljnjeg razvoja
