A CMOS IF transceiver with reduced analog complexity

Signal processing techniques are used to minimize the analog complexity in an intermediate-frequency (IF) transceiver. The receiver digitizes the IF signal directly by subsampling and complex bandpass delta-sigma modulation. A new loop filter is proposed for use in the complex delta-sigma. Digital demodulation and filtering are then used to extract the baseband information. The transmit section converts baseband to IF through an all-digital signal path. A bandpass delta-sigma modulator quantizes the digital IF signal to 1 bit in order to simplify the IF output digital-to-analog converter/driver. The output driver provides analog finite impulse response filtering for quantization noise.