Title :
Digital IF modulator and demodulator design for transmission over band-limited channels
Author :
Wang, X.H. ; QViu, X.Z. ; Codenic, J. ; Vandewege, J. ; De Meyer, K. ; Trog, W.
Author_Institution :
INTEC-IMEC, Ghent Univ., Belgium
Abstract :
This paper describes the design of a digital IF quadrature modem used in a hybrid digital and analog 16 QAM transmitter and receiver architecture for upstream transmission over CATV networks. The digital modem is implemented with high speed and large capacity programmable logic devices. Each incorporates a 20-tap FIR square-root Nyquist matched filter and a frequency conversion circuit. A 9-tap x/sin(x) compensation filter is also accomplished for equalizing the D/A converter spectrum distortion. The measured spectral efficiency is 2.7 b/s/Hz with a intersymbol interference of -30 dB
Keywords :
FIR filters; cable television; compensation; frequency convertors; intersymbol interference; matched filters; mixed analogue-digital integrated circuits; modems; quadrature amplitude modulation; telecommunication channels; television receivers; television transmitters; 16 QAM transmitter; 20-tap FIR square-root Nyquist matched filter; 9-tap x/sin(x) compensation filter; CATV networks; D/A converter spectrum distortion; band-limited channels; demodulator design; digital IF modulator; digital IF quadrature modem; equaliser; frequency conversion circuit; high speed programmable logic devices; hybrid digital/analog architecture; intersymbol interference; large capacity programmable logic devices; receiver; spectral efficiency; transmission; upstream transmission; Circuits; Demodulation; Digital modulation; Finite impulse response filter; Frequency conversion; Matched filters; Modems; Programmable logic devices; Quadrature amplitude modulation; Transmitters;
Conference_Titel :
Signal Processing, 1996., 3rd International Conference on
Conference_Location :
Beijing
Print_ISBN :
0-7803-2912-0
DOI :
10.1109/ICSIGP.1996.566518
