A wideband digital RF receiver front-end employing a discrete-time (DT) filter is presented for application to m-WiMAX (WiBro). By employing a sampling mixer and a DT filter, the receiver operates in the charge domain. In addition to the flexibility of the DT filter, the new non-decimation finite impulse response (NDF) filter can be cascaded to a conventional finite impulse response (FIR) filter without the decimation effect. Thus, we can easily increase the order of the  sincn  function-type filtering response and the signal processing bandwidth. The FIR filter is also modified to reduce the noise and the number of required clock signal. Because of the new filter configuration, clock signals can be shared by the FIR filter and NDF filter and the clock generator circuit can be simplified. The designed receiver front-end is implemented using an IBM 0.13-μm RF CMOS process. The fabricated chip satisfies the m-WiMAX specification of an 8.75 MHz channel bandwidth and the total system current dissipation is 26.63 mA from a 1.5-V supply voltage.
['Heesong Seo', 'Inyoung Choi', 'Changjoon Park', 'Jehyung Yoon', 'Bumman Kim']
A Wideband Digital RF Receiver Front-End Employing a New Discrete-Time Filter for m-WiMAX