First customer for Systolix math processor array

In Analog Devices' data converter, a version of its AD7723 16-bit sigma-delta A/D, the array serves as a programmable notch filter. The converter oversamples (at up to 20 MHz) to extract a clean 1.2-MHz signal. In this application, the PulseDSP array acts as a finite impulse response filter, said Gordon Work, Systolix' managing director.

The PulseDSP-which provides about 130 million MACs to the standard A/D-allows the A/D to be programmed with ideal response characteristics, configuring its low-pass or bandpass frequencies and roll-off characteristics.

The array can support communications applications-controlling filter coefficients, decimation ratio, interpolation, and output rates-processing signals up to 400 MHz, said Work. One example is a decimation filter for RF and IF circuits. The filter will be used to digitally extract a baseband signal from a higher-frequency carrier, he said.

While the configuration of math processing elements in Analog Devices' converter would be either ROM-controlled or mask-programmable, it could be controlled by an EPROM (or an external microprocessor) in other applications. This "field-programmable processor array"-which Systolix calls FPPA-resembles an FPGA because of its flexibility and field programmability.

Unlike FPGAs, the FPPA clocks at higher speeds and is optimized for math processing functions rather than general logic. Like a VLIW processor, the FPPA harnesses a massive amount of parallel processing resources. The difference is that the math processing resources reflect a smaller level of granularity and are hardwired like programmable logic blocks instead of controlled by a very long instruction word.

In this way, hundreds-even thousands-of multiply-accumulate cells can operate simultaneously at video speeds, said Gareth Jones, Systolix' technical marketing manager. This allows up to 10 billion 16-bit MACs per second to be drawn from a 5 x 5-mm, 0.35-micron CMOS die, he said. Systolix believes the technology will spawn families of stand-alone digital filters, as well as custom chip designs.