AD28MSP01

The AD28msp01 is a complete analog front end for high performance DSP-based modems. The device includes all data conversion, filtering, and clock generation circuitry needed to implement an echo-cancelling modem with a single host digital signal processor. Software-programmable sample rates and clocking modes support all established modem standards. The AD28msp01 simplifies overall system design by requiring only +5 volts.

The inclusion of on-chip anti-aliasing and anti-imaging filters and 16-bit sigma-delta ADC and DAC ensures a highly integrated and compact solution for FAX or data MODEM applications. Sigma-delta conversion technology eliminates the need for complex off-chip anti-aliasing filters and sample-and-hold circuitry.

The AD28msp01 utilizes advanced sigma-delta technology to move the entire echo-cancelling modem implementation into the digital domain. The device maintains a 72 dB SNR throughout all filtering and data conversion. Purely DSP-based echo cancellation algorithms can thereby maintain robust bit error rates under worst-case signal attenuation and echo amplitude conditions.

The AD28msp01's on-chip interpolation filter resamples the received signal after echo cancellation in the DSP, freeing the processor for other voice or data communications tasks.