Digital signal processing method and apparatus
AssigneeBritish Broadcasting Corporation
InventorMichael G. Croll
Life of this patent
Estimating the term…
Abstract
Encoded digital television signals having a defined bandwidth are transmitted at reduced bandwidth by regularly omitting (18) one in every n of the signal samples, where n is greater than two and is preferably three or four. At a receiver the omitted samples are regenerated by estimating (26) their values from the samples of the reduced-rate transmitted signal by making use of frequency components outside the normal defined bandwidth of the original signal. The estimation can be achieved by a symmetrical digital transversal filter of which one in every n coefficients is zero, the amplitude/frequency characteristics of the filter being unity throughout the defined bandwidth of the TV signal and antisymmetric about half the mean lower sample rate.
Claims24
A method of processing a digital signal, comprising:
- receiving a digital input signal having a defined bandwidth at a first sample rate;
- regularly omitting one in every n of the input samples to provide a reduced-rate signal at a second, lower sample rate for transmission or processing, where n is greater than two;
- and
- subsequently regenerating the omitted samples by estimating their values from the samples of the reduced-rate signal by making use of frequency components outside the said bandwidth.
A method of forming a digital signal at a higher sample rate from a signal at a relatively lower sample rate which has in turn been formed by omitting one in every n samples from a signal at the higher rate having a defined bandwidth, where n is greater than two, comprising receiving a signal at said lower sample rate, and estimating the values of the omitted samples from the samples of the lower-rate signal by making use of frequency components outside the said bandwidth of the higher rate signal.
A method of forming a digital signal at a higher sample rate from a signal at a relatively lower sample rate which has in turn been formed by omitting one in every n samples from a signal at the higher rate having a defined bandwidth, where n is greater than two, comprising receiving a signal at said lower sample rate, and filtering the received signal with a filter the amplitude/frequency characteristic of which is substantially unity throughout the said defined bandwidth, and is antisymmetric about half the mean lower sample rate.
Apparatus for processing a digital signal, comprising:
- an input for receiving a digital input signal at a first sample rate having a defined bandwidth;
- means connected to the input for regularly omitting one in every n of the input samples to provide a reduced-rate signal at a second, lower sample rate for transmission or processing, where n is greater than two;
- and
- means for subsequently regenerating the omitted samples by estimating their values from the samples of the reduced-rate signal by making use of frequency components outside the said bandwidth.
Apparatus for forming a digital signal at a higher sample rate from a signal at a relatively lower sample rate which has in turn been formed by omitting one in every n samples from a signal at the higher rate having a defined bandwidth, where n is greater than two, comprising an input for receiving a signal at said lower sample rate, and means for estimating the values of the omitted samples from the samples of the lower-rate signal by making use of frequency components outside the bandwidth of the higher rate signal.
Dependencies are inferred from the claim text.