Burr-Brown Corporation announced the DF1704, a high performance, stereo 8X oversampling digital interpolation filter designed for high end consumer and professional audio applications.

An interpolation filter, such as the DF1704, is used to make the reconstructed audio signal truer to the original music by restoring missing sound information between each sample of the digital-to-analog converter (DAC). The DF1704 is the ideal companion for Burr-Brown's PCM1704, the world's highest performance 24-bit BiCMOS, sign magnitude audio DAC.

Specific applications for the DF1704 include high-end CD players, high-end DVD players, digital multi-track and video recorders, and digital effects processors. Moreover, the small package size (28-lead SSOP) makes this device well suited for a wide variety of audio and video systems, as well as musical instruments.

The DF1704 supports 24-bit, 96kHz operation and features user programmable functions, including selectable sharp or slow roll-off filter response, digital de-emphasis, independent L/R attenuation, and input/output data formats.

"Burr-Brown's high performance digital interpolation filter, the DF1704, and high performance BiCMOS Sign-Magnitude DAC, the PCM1704, combine to provide the highest level of audio signal reproduction available today," said Mike Centorino, audio products marketing manager at Burr-Brown.

The PCM1704, with its 120-dB SNR, was featured on these pages a short while ago. This DF1704 is the perfect digital filter companion part for the OEM designer who needs to keep the numbers way "up there" in distinguishing his high-end products; this is now less so for the CD market where standalone players are just about reaching the end of their design lives with the CD specs for DVD now going ahead (which kind of makes billion dollar quotes for the 1997 high-end standalone audio market even more irrelevant.) But the DVD market is going to hit spectacular levels with the third generation machines by mid-1999, and all those CDs you have invested in are not going to go to waste just yet.

The passband ripple of the DF1704 is an extremely impressive ý0.00005 dB. In addition to the top end 24-bit 96-kHz operation, the filter also offers use with 16- and 20-bit inputs and 16-, 18- and 20-bit outputs, while the sampling rates can be as low as 32 kHz; The part has a TTL input interface and provides a 115-dB stopband attenuation and operates from a single 5-V supply.