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New TI Single-Chip Codec Raises Voice Quality While Lowering Power Consumption for CDMA-Based Applications
"TI pioneered voice codecs with its original VBAP products," said Gilles Delfassy, worldwide director of the Texas Instruments Wireless Communications Business Unit and TI vice president. "Now the TWL1101 Voice-Band Audio Processor enhances TI's leadership in wireless analog/mixed-signal technology with features that make the device more widely applicable and provide more system-level control through programming." A Next-Generation Voice Codec The TWL1101 is an enhancement of TI's existing family of VBAP products, which are used extensively in wireless cellular and personal communications systems (PCS) phones, as well as in many other applications. Like the earlier VBAPs, the TWL1101 performs the transmit encoding (analog-to-digital conversion) and receive decoding (digital-to-analog conversion) and provides transmit and receive filtering for wireless phones and other voice-band communications systems. In addition to supporting CDMA systems, the device is also compatible with any other type of application requiring an interface between a human voice and a digital signal processor (DSP) or microcontroller. Systems that can benefit include hands-free cellular kits, speakerphones, answering machines, voice modems, digital intercoms, digital public exchanges (PBXs), wireless local loop handsets, voice interfaces to computers, and voice-activated security systems. Among the TWL1101 enhancements are Sigma-Delta technology and digital filtering, which require less power and produce a higher-quality voice signal compared to earlier codecs. Added sidetone produces a more natural voice sound from the speaker and also simplifies DSP programming by offloading sidetone algorithms. To simplify system clocking, the device generates all necessary internal clocks. All the new features of the TWL1101 VBAP are fully programmable through the I2C Bus™ serial interface. This programmability gives designers added flexibility for controlling all channeling, filter response and bi-directional gain settings and allows selection between 13-bit linear or 8-bit µ-law companded data mode. Two selectable microphone inputs and two selectable speaker outputs ease the implementation of after-market car kits. "The announcement of the TWL1101, coupled with TI’s new LinEPIC III™ process technology, establishes a solid foundation for TI to provide an analog/mixed-signal roadmap for third-generation wireless communication systems," concluded Delfassy. Availability, Pricing, Packaging The TWL1101 VBAP is manufactured using TI's LinEPIC™ process. Available in volume today, the device is priced at $3.45 per unit in quantities of 1,000 and is packaged in a 48-pin thin quad flatpack (TQFP). In addition, TI plans to offer the TWL1101 in a MicroStar™ ball-grid array (BGA) beginning in the fourth quarter of 1998.
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Trademarks:
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DALLAS (Aug. 31, 1998) -- Texas Instruments (TI) today announced a mixed-signal voice coding-decoding device (codec) designed for use in Code Division Multiple Access-based (CDMA) wireless handset applications. The new voice-band audio processor (VBAP™) provides designers with greater programming flexibility and ease of design, while at the same time improving system voice quality and reducing power consumption.
