Flexible and scalable front-end tuner for software defined radio: Page 3 of 5

April 11, 2017 //By Nazzareno Rossetti, Kishore Racherla, Adam Heiberg
Traditional radio receivers require as many radio receiver chips as there are standards. In contrast, Software Defined Radio (SDR) architectures perform the baseband processing using software, enabling reception of a wide range of radio standards with a single radio platform. This article discusses different ways to handle the SDR baseband processing and proposes a cost effective, flexible and scalable implementation that best actualizes the potential of SDR.

The advent of powerful multicore processors has enabled this approach to SDR. With a multicore processor, the software flexibility required by SDR can be pushed inside the main application processor, where one core can be dedicated to each standard. This simplifies the radio design and reduces cost by more efficiently utilizing the multicore application processor already present in the system.

 

Flexibility and scalability

The proposed WBR architecture makes a true SDR possible and is highly flexible and scalable. In the example below (Figure 4) a typical car radio employees three WBR tuner integrated circuits (ICs): one for the main station, one for background scan (searching for alternate frequencies), and one for phase diversity.


Figure 4: WBR scalable architecture.

MAX2175 World Band Radio receiver

The MAX2175 IC is an advanced RF to Bits automotive radio tuner. This highly integrated tuner uses direct conversion for digital audio broadcast (DAB) and digital multimedia broadcast (DMB) applications, covering VHF Band-III and L-Band. Reception of FM, DRM+, FM-HD, and Weather-Band is supported using a Low-IF and digital conversion to baseband. AM (LW, MW, and SW) and DRM reception is supported using direct sampling and digital conversion to baseband (Figure 5).

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