A chip-set for TETRA digital mobile radio

A chipset for the ETSI mobile radio standard TETRA has been designed and fabricated. The design has been split across an analogue custom ASIC and a digital standard cell ASIC. These two chips provide all the conversion and band-limiting functions for both the IQ data path and the voice codec, together with many auxiliary functions required for the baseband analogue and digital signal conditioning. The analogue ASIC implements 3 channels of ADC and DAC using sigma-delta modulation. The transmit data path uses a modified 2^ndorder sigma-delta modulator together with a FIR-DAC structure to meet the stringent out-of-band noise requirements.