Cirrus Logic Inc. highlighted its Crystal audio technology and system-chip expertise with the introduction of the industry's most highly-integrated sample rate converter for consumer and professional audio systems. The new single-chip Crystal solution delivers the functionality currently performed by as many as three separate components. Moreover, the new chip's innovative architecture is capable of processing the widest array of audio standard rates ranging from 8kHz to 96kHz. As the only audio device that supports the variety of audio sample rates used across broadcast, compact discs, PC audio, movie soundtracks and professional audio systems, the CS8420 dramatically simplifies audio system design and eliminates compatibility issues.

In addition to providing the industry's first 24-bit digital sample rate converter, the new chip also incorporates a digital audio receiver and transmitter compatible with both professional and consumer audio standards (AES/EBU and S/PDIF respectively), significantly reducing the cost and size of audio system electronics. With its highly-integrated, high-performance functionality, the CS8420 offers audio system designers the flexibility to create consumer and professional audio systems that can process digital audio signals from any consumer or professional audio equipment, including audio mixing consoles, multi-track recorders, DVD authoring systems, studio-to-transmitter links and effects processor systems.

"The CS8420 offers more features than any other sample rate converter available in the market today. Using 0.35 micron technology and advanced Crystal algorithms, the CS8420 provides a level of integration that to date has not been achievable in sample rate converters," said John Paulos, vice president of audio for Cirrus Logic's Crystal Semiconductor Products Division. "This announcement expands the extensive portfolio of Crystal consumer and professional audio products. Crystal now provides complete audio solutions, from input (Rx) to output (Tx), analog signal processing and conditioning (ADC, DAC, Codec), Digital Signal Processing (DSP), and control of all the varying sample rates (SRC) found in today's complex digital audio equipment."

Simplifying Professional Audio System Design

Offering a conversion rate of 8kHz to 96kHz, within a 1:3 to 3:1 ratio, the CS8420 provides by far the widest conversion ratio of any sample rate converter solution today. With the CS8420, digital audio data can be sent at any commonly used sample rate and the device will automatically convert the data to the sample rate required by the specific digital audio system. This simplifies the clocking architecture of the audio system because it only has to support one sample rate internally instead of the many sample rates recognized at the input.

High Performance/Quality Sound

Unlike more limited sample rate converters the new Crystal audio solution maintains the quality of the audio signal as it goes through the sample rate conversion process. The device supports 24-bit input and output resolution that allows customers to connect a 24-bit audio source or 24-bit audio D/A converter to the device without suffering any degradation in performance. Further, the CS8420 uses a correctly dithered truncation technique to also support output word sizes of 16- or 20- bits, maintaining audio quality across a variety of systems. In addition, with a 120 dB dynamic range, as well as a total harmonic distortion + noise (THD+N) of typically -117 dB, the CS8420 does not degrade the sound quality through the sample rate converter process, providing far superior performance compared to ý- 100 dB of other commonly used solutions.

There is little to say about this part that the press release does not say quite well. This is the audio designer's dream rate converter. It allows complete freedom of moving from one standard to another with little difficulty and extremely high quality -- as much as the change allows for the particular conversion and direction. The secret is in the internal processing with 24-bit handling and dynamic range and noise numbers that are right on the edge of the very best available in audio processing today.

Cirrus are doing well with the Crystal product line and this part will be extremely successfull for them. It is priced for professional systems and will be handsomely profitable. The CS8420 is in a 28-pin SOIC, sampling in this quarter, and will be in full production early in 1999; it is priced at $13.90 in 1000-piece lots.