A novel FM/FSK based receiver front-end for MedRadio spectrum in 401–406 MHz band

A novel receiver front-end is proposed for FM/FSK modulated signal, which is transmitted from a body worn device in the MedRadio spectrum of 401–406 MHz. The front-end comprises a low noise amplifier (LNA), a zero crossing detector (ZCD) and a frequency to digital converter (FDC). The proposed architecture offers direct digitization of the input signal and is immune to LO leakage and problem of image frequencies. Designed in 180 nm mixed mode CMOS technology, the worst case post layout simulation results show a sensitivity of −80 dBm at 200 kbps for FSK modulated input with only 990 μW power consumption.