如何给便携式设备添加音乐和数据传输功能

ns that require a much larger and more expensive antenna. The ability to use a miniature AM ferrite antenna makes it truly possible to add AM radio to any handset or MP3 player.

Another challenge for the portable device maker is that complex designs often reduce yields, which can be very costly in consumer products. A digital-centric architecture is also helpful in improving manufacturability. A digital approach eliminates the need for manual alignment, which can take up to several minutes per device in the manufacturing process. Traditional AM/FM solutions require multiple stages of hand-tuning that adds cost, limits production flow and introduces performance variability across products. The elimination of any hand tuning during the manufacturing process dramatically reduces the complexity, cost and risk associated with adding FM/AM to the portable device.

The reduced bill of materials of course, also reduces complexity in manufacturing and improves yields. And, a built-in DSP offloads host resources and speeds software development by providing integrated digital tuning, AM/FM decoding, seek, soft-mute and FM stereo blend. This also allows for pre-testing. Older solutions cannot be tested without the IC in addition to 45+ extra components on the board, thus leading to lower yields and increased costs.

Ultimately, the end user does not care what type of antenna was used or what type of architecture the radio has, they just want a small, sexy device that sounds good. The ability to offer good quality reception and added features like RDS decoding, is very important to the end user experience.

RDS offers useful digital data related to both FM broadcast and traffic messaging. Cell phone operators, portable media players and navigational device OEMs can use this data to drive new usage models and new revenue. Consumers have grown accustomed to seeing information displayed about the audio they are hearing, such as song name, artist and album, or program name, analyst and program commentary, and portable AM/FM receivers have not historically been able to provide this feature. Therefore, adding the visual element to the AM/FM radio broadcast experience is a good way to differentiate a portable device. But, integrating an RDS-capable AM/FM receiver into devices that are becoming progressively smaller has various challenges.

The Radio Data System (RDS) provides a way device manufacturers can incorporate display functionality into AM/FM broadcast products. RDS is digital data broadcast on a sub-carrier to the AM/FM signal and typically contains information relevant to the tuned channel and the broadcast programming in process. RDS is also used to carry traffic messaging (TMC) regarding road conditions and delays in a geographic area. TMC is typically loaded into the broadcast network by an organized series of reporting mechanisms including road-side cameras, emergency personnel, driver call-ins, and construction information. Makers of GPS navigational devices leverage TMC information to identify blockages and chart paths around them, allowing users to benefit from real-time information coupled with the less dynamic regional maps used by GPS devices.

Traditionally, analog radio solutions have too many components and limited programmability, making the addition of RDS too challenging. With limited memory and only half of the four available RDS blocks in an RDS group, the host processor must clear the FM receiver’s RDS memory buffer before it is able to decode and present the second h