Integrated CMOS transceivers using single-conversion standard IF or low IF RX for digital narrowband cordless systems

This paper describes a 0.25 /spl mu/m CMOS transceiver operating in the 902-928 MHz ISM band for US Narrowband Digital Cordless Telephony. The DS9RF31 transceiver, intended for TDD systems, meets all specifications while providing a low cost, small the size solution. The transmitter uses open-loop FSK modulation and the receiver uses a single-conversion image-reject architecture followed by an IF chain and demodulator that provides output data to a baseband IC for further processing. One version of the chip uses a standard 10.7 MHz IF with discrete channel filters. A second version (DS9RF32) integrates the IF channel filter by using a low-IF of 1.36 MHz.