Study And Implementation Of Radio-Frequency Circuit In CDPD Mobile Terminal

With the development of wireless communication and computer communication, the demand for data service through wireless method increased dramatically. CDPD (Cellular Digital Packet Data), as one of the most practical methods to meet the requirement, has been adopted more and more widely. So it is very meaningful and important to develop related products for CDPD. This paper focuses on the RF board of the CDPD modem, which is the critical part of a CDPD wireless terminal. The implementation of this project is based on CDPD VI. 1.A proper implementation scheme was proposed. Suitable devices were selected to meet the performance requirements in CDPD. Critical circuits in developing this board, such as tht modulation circuit, demodulation circuit, PLL and filter, were analyzed in detail. Parameters adopted in these circuits were also calculated. Based on all that mentioned above, a RF board was implemented and related tests and experiments were successfully done as well.