US 5,208,596 A · DAC distortion compensation

Abstract

The present invention is directed to compensating the sin (x)/x response attendant the output signals from a Digital-To-Analog converter in systems consisting of the cascade connection of a digital processor having a non-uniform frequency response h(nT) and a Digital-To-Analog converter. This is accomplished by altering the processor to provide a frequency response of h(nT)*g(nT), where h(nT) is the impulse response of the processor, g(nT) is the impulse response of the reciprocal of the frequency response of the DAC, and the asterisk represents convolution. Alternatively, if the Fourier transform of the frequency response of the processor is given by F(.omega.), and the DAC exhibits a frequency response S(.omega.), which is the frequency transform of the time response of the DAC sample and hold type output, then the processor is substituted with one having a frequency response defined by the inverse Fourier transform IF(F(.omega.)/S(.omega.))) over the frequency band of interest.

Claims10

Dependent claims

Signal processing apparatus of the type including a cascade connection of a digital filter and a digital to analog convertor, and wherein said digital filter is incorporated to perform a filter function defined by the impulse response function h(nT), said apparatus improved by conditioning said filter to exhibit an impulse response function h'(nT) given by

h'(nT)=h(nT)*g(nT)
where g(nT) corresponds to the reciprocal of the time response of undesirable frequency characteristics G(.omega.) of said digital to analog convertor, the asterisk designates convolution, n is an index integer and T defines the period between samples applied to said digital to analog convertor.

Signal processing apparatus of the type including a cascade connection of a digital filter and a digital to analog convertor, and wherein said digital filter is incorporated to perform a filter function defined by the frequency response H(.omega.), said apparatus improved by conditioning said filter to exhibit a frequency response H'(.omega.) given by

H'(.omega.)=H(.omega.)/G(.omega.)
where G(.omega.) corresponds to undesirable frequency response characteristics of said digital to analog convertor and .omega. represents frequency in radians.

Dependencies are inferred from the claim text.

DAC distortion compensation

Life of this patent

DAC distortion compensation

Life of this patent

Abstract

Claims10