New Jennic reference design is first to provide speech audio solution for IEEE 802.15.4 applications

Jennic Ltd. has introduced a reference design which enables speech to be transmitted over an IEEE802.15.4 link using the company's JN5139 single chip wireless microcontroller. The ready made hardware and software design solution has been introduced as a result of customer demand for audio functionality and is aimed at applications from wireless headsets to network wide audio. The design has a bill of materials (BOM) cost of under $6 for the complete implementation.

Jennic's IEEE802.15.4 audio reference design provides several key benefits for audio applications - low power operation with instant response and long standby battery life; secure speech with 128-bit AES encryption; simple development with no complex profiles, a range of greater than 200 meters, and more addressable nodes than Bluetooth, making it suitable for public address or broadcast applications. Applications include emergency services' helmet to PMR radio, providing a fireproof and secure alternative to cables for communication from helmet to radio, and for applications including VOIP headsets and low power door intercoms.

Voice compression in the new audio reference design is implemented in software on Jennic's standard 32-bit CPU - this is the only single chip solution capable of delivering the required processing power for ADPCM compression as well as the protocol and application. Jennic's solution also features a hardware AES co-processor, making security transparent to the processor and removing the need for software support. RF channel agility ensures good performance even in the presence of interference from wireless LAN. The design features excellent audio performance, with THD+noise being better than -77dB

The software features of the audio reference design include full duplex, half duplex (push-to-talk) or simplex configurations, ADPCM compression giving 32kbps per audio stream, 8/16kHz switchable sample rate, volume control, low battery indicator, and 400Hz test tone if required. The design can also support push-to-talk functionality. For evaluation, the new audio reference design plugs into the expansion connector on Jennic evaluation kits, and features standard 3.5mm jack interfaces for external microphone and earpiece.

The audio reference design provides hardware schematics and board layouts, together with example software code and a comprehensive reference manual. It is available from Jennic now.

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