Design and Implementation of Digital LMR Walky-Talky for APCO P25 Phase II

In this paper, digital LMR walky-talky was designed and fabricated for APCO P25 phase II. For linearization of RF transmitter, CFL ASIC was designed and implemented using 0.35 um CMOS process. Using CFL chip, the IMD characteristic of Tx PA was improved more 30 dBc when two-tone was injected and FCC emission mask was satisfied at 35.6 dBm output when modulated signal CQPSK was injected. Reference sensitivity level was -119 dBm, co-channel rejection was 6 dB. Except the adjacent channel rejection, the others were generally satisfied with APCO P25 specifications.