A Digital-Front-End Enhanced Multi-Mode/Multi-Standard Wireless Receiver

This paper presents a multi-mode receiver concept for different transmission standards like UMTS and IS95. Due to the use of a Digital-Front-End (DFE) the requirements for the analog part of the well known direct conversion receiver (DCR) architecture decrease because channelization and fine frequency tuning are shifted from the analog into the digital domain. The adaptation of the channelization requirements subjected to the different transmission standards is limited in the analog domain by nature of their implementation. Shifting this functionality into the DFE greatly easies this task due to the availability of highly reconfigurable digital filter structures. Another challenge is the analog to digital conversion which is carried out with a high dynamic-range/low-power ∆Σ -analog-to-digital-converter (ADC). The DFE also carries out an integer and fractional sample rate conversion to expand the flexibility and satisfy the requirements of different digital base band integrated circuits (BB-IC). Key-Words: Direct-conversion-receiver, Analog-to-digital-converter, Software-defined-radio, Multi-mode, WCDMA, Fractional-sample-rate-conversion