Software-defined radio (SDR) performs baseband processing via software, a process that enables reception of a wide range of radio standards on a single radio platform. This approach is necessary for smart multimedia touchscreen systems in cars. Traditional radio receivers, by contrast, require as many radio receiver chips as there are radio standards.
An SDR approach can be used to implement all post analog-to-digital converter (ADC) signal processing. To simplify the design and enable greater efficiency, some of the functions can be implemented in hardware in the front end. For a simpler interface, you can implement decimation, which reduces the bandwidth of the interface between the front-end device and the SDR processor, in the front end. Any signal processing that you designate to the front-end must be sufficiently adaptable, so that you don’t compromise the flexibility of the SDR backend. Ideally, in an SDR implementation, signal processing that’s unique to a particular standard should be implemented using SDR techniques. This way, you can use a single radio front-end with various broadcast standards through the SDR software.
Fig 1. MAX2175 functional block diagram
Even though baseband processing can be implemented in software with SDR, the software still has to run on a hardware platform. In one potential approach, you can have two baseband signal processing cores on the same chip, each with its own front-end, for AM and FM. But since there are more standards than this, this type of architecture wouldn't fully support an SDR strategy. To fully realize the intention of SDR, you’ll need a more flexible architecture. Maxim proposes World Band Radio (WBR), a stand-alone front-end tuner that can implement all primary analog and digital radio standards. This tuner, together with an SDR backend, allows a single radio platform to receive all global radio standards.
To learn more about how WBR can help you achieve the full potential of SDR, read our Design Solution, "Choose a Flexible and Scalable Front-End Tuner for Your Software Defined Radio."