Title :
Analog baseband processor for CDMA/FM portable cellular telephones
Author :
Nettles, M. ; Menping Chang ; McAllister, G. ; Nise, B. ; Persico, C. ; Sahota, K. ; Tero, J.
Author_Institution :
Qualcomm Inc., San Diego, CA, USA
Abstract :
62The analog baseband processor is designed for use in dual-mode CDMA/FM cellular telephones, and contains both receive (RX) and transmit (TX) circuitry. The challenge presented by this circuit is to maintain low noise and precise filter characteristics in a high-gain, high-offset system and to recover a small input signal (1mVrms) in the presence of a large jammer (800mVpp). The primary function of the RX circuitry is the down-conversion of IF (intermediate frequency) to analog baseband followed by conversion to digital signals. TX circuits convert digital data into analog baseband signals that are then up-converted to IF. Both CDMA and FM analog processing are done by the circuit. A corresponding digital processor completes the CDMA and FM processing tasks.
Keywords :
analogue processing circuits; cellular radio; code division multiple access; frequency modulation; land mobile radio; mobile radio; telephone sets; IF system; analog baseband processor; digital signals; down-conversion; dual-mode CDMA/FM portable cellular telephones; filter; high-gain high-offset system; jammer; noise; receive circuitry; transmit circuitry; up-conversion; Baseband; Circuit noise; Circuit optimization; Clocks; Filtering; Frequency modulation; Low pass filters; Multiaccess communication; Telephony; Voltage-controlled oscillators;
Conference_Titel :
Solid-State Circuits Conference, 1995. Digest of Technical Papers. 41st ISSCC, 1995 IEEE International
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-7803-2495-1
DOI :
10.1109/ISSCC.1995.535575
