Reference Design

Complete Two-Way Crossover Network in a Single Chip

Quickfilter Technologies Programmable Digital Filter, QF1D512, can now be configured to provide complete two-way audio crossover network. High-quality sound usually available only in high-end audio systems now possible with low-cost Quickfilter device.

Source: Quickfilter Technologies, Inc.
6/27/2008

Quickfilter Technologies reference design allows a single QF1D512 SavFIRe (Simple and versatile FIR engine)IC to be configured to provide the complete digital filtering for a two-way audio crossover network. Using this solution, designers can now achieve exceptionally high-quality filtering that is generally seen only in high-end audio systems with a programmable digital filter device that costs less than 1/3 the cost of an equivalent DSP previously used to perform these functions.

The QF1D512 SavFIRe is a programmable digital filter designed for seamless insertion in the serial data path of a digital filter or used as an FIR coprocessor. The device can be easily programmed using the Quickfilter Design Software to support virtually any FIR digital filter configuration. This specific circuit example shows the device operating between the analog inputs and outputs of a codec to provide a complete audio crossover network. In this configuration, exceptionally high quality filtering generally seen only in high-end systems is available over a broad range of ADC data rates with resolutions up to 24 bits.

In the two-way audio crossover configuration, the QF1D512 SavFIRe IC enables 100dB attentuation in stop band and better than 24dB per octave attenuation in transition band based on 48 kHz sampling and a 1500 Hz crossover. The combined response is perfectly flat over the entire frequency band.

This configuration can be applied to both wired and wireless audio systems including wireless speakers, devices which plug into iPods(R) and audio systems for stereo networks.