1. Field of the Invention
This invention relates to a digital decimation and compensation filter system for use in an analog-to-digital conversion circuit.
2. Brief Description of the Related Technologies
Converting analog signals to digital signals is accomplished using an analog-to-digital converter (ADC). ADCs in the field of PC audio applications typically incorporate a sigma-delta modulator, which converts an analog input signal to a digital output signal. The sigma-delta modulator typically oversamples an analog input signal and outputs an oversampled digital output signal.
A digital decimation filter is required to down-sample, or decimate, the output of the sigma-delta modulator and to filter the digital signal such that a proper frequency response and signal-to-noise ratio are achieved. Many decimator filters require the use of numerous coefficients for greater precision, requiring numerous taps, which increases the complexity and expense of designing and manufacturing such an intricate filter. The greater number of coefficients in these decimation filters creates inherent complexity and associated costs. The need for a high precision, low cost, digital decimation filter, and a compensation filter to compensate for attenuation caused by circuitry in the ADC, exists.