Convertor mops up basestation signal processing

The newest member of Analog Devices' VersaCOMM family of digital convertors, the AD6623 is a 104Msample/s, four-channel transmit signal processor for multimode multistandard wireless basestations.

The newest member of Analog Devices' VersaCOMM family of digital convertors, the AD6623 is a 104Msample/s, four-channel transmit signal processor (TSP) designed for multimode multistandard wireless basestation architectures.

The AD6623 is used in the transmit signal path to process the signals from a general purpose DSP for input to a high-speed digital-to-analogue convertor such as the ADI TxDAC.

From the baseband data provided by the DSP, the TSP creates the high-bandwidth real or complex data needed to drive the TxDAC.

The TxDAC then outputs the first intermediate frequency (IF) directly in the analogue domain.

The AD6623 contains four identical digital TSPs complete with synchronisation circuitry, and a cascadable wideband channel summation stage.

On-chip tuners allow the relative phase and frequency for each of the four RF output carriers to be independently controlled.

Each channel accepts input data from independent serial ports that may be connected directly to the serial port of the DSP devices.

The RAM-based architecture of the AD6623 allows easy, on-the-fly, reconfiguration to accommodate multi-mode operation in compliance with both digital and analogue air interface standards.

Modulation, pulse-shaping and anti-imaging filters, digital resampling, scaling, static equalisation and tuning functions are among the many signal processing functions integrated into this cost-effective communication solution.

The AD6623 TSP enables designers to use the high-level of performance afforded by TxDACs to move to digital IF basestation architectures.

Digital IF signal processing simplifies system design, provides repeatable manufacturing, higher accuracy, and provides more flexibility than comparable high-dynamic range analogue designs.

The AD6623 supports multicarrier: GSM/Edge, IS95, cdma2000, and UMTS cellular air standards.

The AD6623 uses a 3.3V I/O power supply and a 2.5V core power supply.

All I/O pins are 5V tolerant and LVCMOS compatible.

All control registers and coefficient values are programmed through a generic microprocessor interface; Intel and Motorola bus modes are supported.

The AD6623 is packaged in a 128-pin MQFP or 196-pin BGA, and is priced at $23.76 (both versions) per unit in 1000-piece quantities.

Samples, evaluation boards, and configuration software are available now.

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