USB-Based Wireless Headset Targets VoIP

VoIP tech toys on your holidays list? With the holidays right around the corner perhaps you've already made your list and checked it twice. Instead of asking for new socks or that leaf blower you'll use to make your neighbors 'real' happy, perhaps you should check out this new toy.

Vishay RFWaves design for a USB-based wireless headset using a fully digital 2.4-GHz wireless link. Target applications for the system include VoIP, PC-based cordless telephony, and PC-based "intelligent" toys.

The new design uses the Vishay RFWaves RFW322-M 3-Mbps direct sequence spread spectrum (DSSS) half-duplex transceiver as its core component and includes specifications for both the wireless headset/handset and the USB dongle.

The RFW322-M provides an output power of 7 dBm and receiver sensitivity of -75 dBm while delivering 16-bit PCM, 8,000 samples/second voice quality. The specified operating range for the design is 6 meters and can be extended to 25 meters with the addition of an RF power amplifier. The high 2.4-GHz bandwidth of the RFW322-M and the exceptional link robustness results in a very reliable and high-quality voice link. The use of printed diversity antennas for the USB further helps to overcome link losses.

The USB dongle component of the reference design specifies the use of a microcontroller to exchange voice/data packets with the PC, to execute a proprietary wireless communication protocol to transfer data over the air and to perform an antenna diversity algorithm. The dongle uses the Vishay RFWaves RFW322-M as its wireless transceiver. The dongle is powered by the USB port and typically draws 70 mA.

In the remote headset/handset unit, a microcontroller executes the proprietary communication protocol to exchange data with the USB dongle while feeding incoming data to a high-quality mixed-signal codec. The codec provides analog signals for the speaker and microphone in the headset or handset. The remote unit draws 40 mA and is designed to run for up to four hours from a single lithium-ion battery cell.

The system has been designed and tested to coexist with 802.11b/g and Bluetooth(R) and is compliant with FCC, ETSI, and Telec regulations.

Link to reference design brochure:

Datasheet on RFW322-M Transceiver Module:

Datasheet on RFW322-M-PA Transceiver Module with Power Amplifier:

Posted on Nov 30, 2005  Reviews | Share |  Digg
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