Direct Conversion Receiver for Personal Communication Systems

Download or read book Direct Conversion Receiver for Personal Communication Systems written by Konstantinos Voudouris and published by . This book was released on 1993 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes direct conversion techniques for radio receivers in the 2 GHz frequency band, with particular reference to personal communications terminals for the Digital European Cordless Telecommunications (DECT) standard. The advantages of the direct Conversion Receiver (DCR) such as the elimination of image spurious response, good selectivity, low power consumption and small size make it attractive in applications such as paging receivers. These applications are, however, at frequencies up to 450 MHz and previously results without hardware details for the 2 GHz band have been reported. This work presents results from a practical study of a DCR and its subsections, namely, power splitter, branch coupler hybrid, coupled lines band-pass filter, low-pass filter, balanced mixer and oscillator. Useful design equations, graphs and a software tool named ÀP(gamma,omega)' are presented for the design of the passive and active elements. The lumped element design of these circuits is taken into consideration looking ahead to possible Monolithic Microwave integrated Circuits (MMIC) applications. Small- and large-signal models are derived for the frequency conversion components; a dual-gate GaAs MESFET and a Schottky beam-lead diode. The large signal behaviour of the two mixers is very good with 1dB compression gain at 7 and 4.8 dBm, and third order intercept point at 40 and 46 dBm, for the dual-gate FET and the diode mixer respectively. The DCR overall performance is analysed with the aid of the Èesof-Omnisys' simulator. The system is based on measured figures of the individual subcircuits. The input is 50mu s bit duration GMSK modulated signal. Typical values for the signal-to-noise ratio is 10 to 12 dBm for 10-3 bit error rate. The receiver can tolerate amplitude and phase mismatches of 3% and 5 degrees respectively, as well as +-1.2 kHz local oscillator drift. The dynamic range is 80dB. The performance of the DCR fits well with the DECT specification.