Title :
A track&hold-AGC suitable for downconversion by subsampling
Author :
Vasseaux, T. ; Huyart, B. ; Loumecu, P.
Author_Institution :
Ecole Nat. Superieure des Telecommun., Paris, France
Abstract :
To date, high-speed CMOS transistors can operate in the GHz frequency range and as result high sampling frequency can be obtained. Thus, a receiver architecture using the sub-sampling principle to downconvert the signal can be now considered as a promising alternative to other kinds of architectures. In effect, sub-sampling systems are potentially more compact and more efficient, because the A/D converter is closer the antenna. In this paper, we show how it is possible to use switched-capacitor techniques to make a track-and-hold mixer and an AGC in the same circuit. This circuit is destined for the front-end of a receiver. For the basic configuration of the circuit, measurements have shown that a signal around 900 MHz could be demodulated to low frequency. An IIP3 of 19 dBm has been proved and at the same time, unfortunately, a noise figure of 20 dBm has been obtained
Keywords :
CMOS analogue integrated circuits; UHF integrated circuits; automatic gain control; demodulators; integrated circuit noise; jitter; mixers (circuits); radio receivers; signal sampling; switched capacitor networks; 900 MHz; A/D converter; ADC; CMOS chip; RF receiver; SC techniques; demodulation; direct conversion; downconversion; noise figure; receiver architecture; subsampling; switched-capacitor techniques; track/hold mixer; track/hold-AGC circuit; Antenna measurements; Band pass filters; Circuit noise; Frequency measurement; Noise figure; Noise measurement; Radio frequency; Sampling methods; Switched capacitor circuits; Switching circuits;
Conference_Titel :
Electronics, Circuits and Systems, 1999. Proceedings of ICECS '99. The 6th IEEE International Conference on
Conference_Location :
Pafos
Print_ISBN :
0-7803-5682-9
DOI :
10.1109/ICECS.1999.814461
