Bandpass Continuous-Time Delta-Sigma Modulator for Wireless Receiver IC
Bandpass ADC is well known to be adopted in the narrow-band receiver design in order to reduce the system complexity, increase integration and improve performance by digitizing the bandpass signal directly without prior conversion to baseband. A fully differential feed forward fourth-order continuous-time bandpass delta-sigma modulator is presented. The proposed single-bit modulator can receive 172.8 kHz IF signals by using an oversampling clock frequency of 5.53 MHz with an OSR of 128. Simulated result showing that dynamic range of 78 dB within bandwidth of 21.6 kHz is achieved and the current consumption is around 1.2 mA at 1.5V power supply.