DSP-based Digital AM/FM Radio Chipset Directly Digitizes IF

STMicroelectronics has begun sampling a new AM/FM radio receiver chipset that directly digitizes the 10.7MHz intermediate frequency in IBOC (In-Band On-Channel) digital radio applications. The new chipset consists of an analog front-end chip in the 0.7-micron BiCMOS process (TDA7515) and a digital AM/FM IF sampling processor in 0.18-micron CMOS (TDA7580). The offering also includes embedded DSP software for implementing advanced algorithms for boosting receiver performance jointly developed by ST and Bose Corporation.

According to the company, the new design also features the implementation of complex equalization techniques that can be deployed to reduce multipath reception effects from adjacent channels. In addition, the chipset’s software design approach will allow additional features to be added later without requiring a hardware redesign. 

ST claims that the new chipset  will smooth the path towards dual standard IBOC/FM receivers by allowing a single DSP to be equipped with the software for handle both. This should give the IBOC-equipped radio a user-transparent FM fallback mode when encountering borderline reception conditions. In addition, the chipset offers support for tuning frequencies worldwide, allowing a single application to cover all markets by simply making software changes.

ST’s DSP software for the TDA7580 includes the implementation of algorithms developed jointly by ST and Bose Corporation. However, system designers using the chipset may also elect to modify or extend a portion of the standard software package for the purpose of adding new features or for embedding their own proprietary technology.

The TDA7515 and TDA7580 chips are supplied in 44- and 64-lead TQFP packages, respectively. According to the company, very few external components are required because most functions are performed digitally. In addtion, a hardware decoder for Radio Data System (RDhas been included in the TDA7580 so that RDS decoding can be performed without placing additional demands on any DSP resources.

Already sampling, the TDA7515 and TDA7580 are scheduled to reach volume production in 4Q02.