Digital interpolation circuitry

Claim 2

A sampled data interpolator comprising: an input terminal for receiving a sampled data input signal; a linear interpolator coupled to said input terminal for providing linearly interpolated samples at an output terminal thereof; a finite impulse response filter coupled to said input terminal, for providing filtered samples corresponding to a compensating signal; weighting means, coupled to said filter, for scaling said compensating signal by a normalized sinc function to provide scaled samples at an output terminal thereof; and means, coupled to the output terminals of said weighting means and said linear interpolator for additively combining said linearly interpolated samples and said scaled samples.

Claim 3

A sampled data interpolator comprising: an input terminal for receiving a sampled data input signal; a linear interpolator coupled to said input terminal for providing linearly interpolated samples at an output terminal thereof; a finite impulse response filter coupled to said input terminal, for providing filtered samples corresponding to a compensating signal, said filter having a transfer function, H, given by ##EQU3## where n is an index; T represents a sample period; g(nT) correspond to input sample values; M is a number equal to one half the number of input samples used by the filter to form a filtered sample, and k n are given by ##EQU4## for all n except zero and one, and ##EQU5## for n equal to zero and one; weighting means, coupled to said filter, for scaling filtered samples and providing scaled samples at an output terminal thereof; and means, coupled to the output terminals of said weighting means and said linear interpolator, for additively combining said scaled samples and said interpolated samples.

Claim 4

A sampled data interpolator comprising: an input terminal for receiving a sampled data input signal; a linear interpolator coupled to said input terminal for providing linearly interpolated samples at an output terminal thereof; a finite impulse response filter coupled to said input terminal, for providing filtered samples corresponding to a compensating signal, said filter having a transfer function, H, given by ##EQU3## where n is an index; T represents a sample period; g(nT) correspond to input sample values; M is a number equal to one half the number of input samples used by the filter to form a filtered sample, and k n are given by ##EQU4## for all n except zero and one, and ##EQU5## for n equal to zero and one; weighting means, coupled to said filter, for scaling filtered samples and providing scaled samples at an output terminal thereof; and means, coupled to the output terminals of said weighting means and said linear interpolator, for additively combining said scaled samples and said interpolated samples.

Claim 5

A sampled data interpolator as set forth in claim 2 wherein said weighting means scales samples by a normalized sinc function.

Claim 6

A sampled data interpolator as set forth in claim 2 wherein said normalized sinc function corresponds to ##EQU6## where d corresponds to the position of an interpolated sample between two input samples in terms of a fraction of a sample period T, and d n corresponds to a normalizing position typically T/2.

Claim 7

A sampled data interpolator comprising: an input terminal for receiving a sampled data input signal; a linear interpolator coupled to said input terminal for providing linearly interpolated samples at an output terminal thereof; a finite impulse response filter coupled to said input terminal, for providing filtered samples corresponding to a compensating signal; weighting means, coupled to said filter, for scaling said compensating signal by a normalized sinc function to provide scaled samples at an output terminal thereof, and wherein said normalized sinc function corresponds to ##EQU7## where d corresponds to the position of an interpolated sample between two input samples in terms of a fraction of a sample period T, and d n corresponds to a normalizing position typically T/2; and means, coupled to the output terminals of said weighting means and said linear interpolator for additively combining said linearly interpolated samples and said scaled samples.

Claim 8

A sampled data interpolator comprising: an input terminal for receiving a sampled data input signal; a linear interpolator coupled to said input terminal for providing linearly interpolated samples at an output terminal thereof; a finite impulse response filter coupled to said input terminal, for providing filtered samples corresponding to a compensating signal; weighting means, coupled to said filter, for scaling said compensating signal by a normalized sinc function to provide scaled samples at an output terminal thereof, and wherein said normalized sinc function corresponds to ##EQU7## where d corresponds to the position of an interpolated sample between two input samples in terms of a fraction of a sample period T, and d n corresponds to a normalizing position typically T/2; and means, coupled to the output terminals of said weighting means and said linear interpolator for additively combining said linearly interpolated samples and said scaled samples.

Claim 9

A sampled data interpolator comprising: an input terminal for receiving a sampled data input signal; a linear interpolator coupled to said input terminal for providing linearly interpolated samples at an output terminal thereof; a finite impulse response filter coupled to said input terminal, for providing filtered samples corresponding to a compensating signal, said finite impulse response filter having a transfer function, H, given by ##EQU8## where n is an index; T represents a sample period; g(nT) correspond to input sample values; M is a number equal to one half the number of input samples used by the filter to form a filtered sample, and k n are given by ##EQU9## for all n except zero and one, and ##EQU10## for n equal to zero and one; weighting means, coupled to said filter, for scaling said compensating signal by a normalized sinc function to provide scaled samples at an output terminal thereof; and means, coupled to the output terminals of said weighting means and said linear interpolator for additively combining said linearly interpolated samples and said scaled samples.

Claim 10

A sampled data interpolator comprising: an input terminal for receiving a sampled data input signal; a linear interpolator coupled to said input terminal for providing linearly interpolated samples at an output terminal thereof; a finite impulse response filter coupled to said input terminal, for providing filtered samples corresponding to a compensating signal, said finite impulse response filter having a transfer function, H, given by ##EQU8## where n is an index; T represents a sample period; g(nT) correspond to input sample values; M is a number equal to one half the number of input samples used by the filter to form a filtered sample, and k n are given by ##EQU9## for all n except zero and one, and ##EQU10## for n equal to zero and one; weighting means, coupled to said filter, for scaling said compensating signal by a normalized sinc function to provide scaled samples at an output terminal thereof; and means, coupled to the output terminals of said weighting means and said linear interpolator for additively combining said linearly interpolated samples and said scaled samples.