Embedded design: Reference design helps engineers add frequency equalization

Quickfilter Technologies announced a reference design to help engineers configure a single FIR-engine IC to provide multiple channel filtering in a single device. Using this solution, designers can implement audio equalization for left and right stereo channels for embedded devices.
By Control Engineering Staff October 25, 2007

Quickfilter Technologies announced a reference design to help engineers configure a single FIR-engine IC to provide multiple channel filtering in a single device. Using this solution, designers can implement audio equalization for left and right stereo channels for embedded devices. When paired with just an inexpensive codec, the QF1D512 SavFIRe chip provides a complete equalizer solution at a very low cost. Announced in September 2006, the chip allows systems designers to quickly and easily add precision digital filtering to an application. The chip can simply be added between an existing analog-to-digital converter (ADC) and the host controller (microcontroller, microprocessor, digital signal processor, or FPGA), or can be connected as a co-processor for controllers with embedded ADCs.
For example, in the two-channel equalizer configuration, the chip can implement a 200 Hz-20 kHz band pass filter. The filter will reject better than 24 dB per octave in the transition band based on a 44.1 kHz sampling rate. With the company’s QuickPro design tools, the engineers can implement virtually any “sound shaping” filter.
A configuration based on the reference design will work for both wired and wireless audio systems, including wireless speakers, stereo headsets, docking stations for MP3 players and satellite radio systems, and audio systems for stereo networks.
C.G. Masi , senior editor