US PATENT SUBCLASS 348 / 392
.~.~.~ Sub-Nyquist sampling


Current as of: June, 1999
Click HD for Main Headings
Click for All Classes

Internet Version by PATENTEC © 1999      Terms of Use



348 /   HD   TELEVISION

384  DF  BANDWIDTH REDUCTION SYSTEM {7}
390  DF  .~ Bit-rate reduction {11}
391  DF  .~.~ Specified color signal {3}
392.~.~.~ Sub-Nyquist sampling


DEFINITION

Classification: 348/392

Sub-Nyquist sampling:

(under subclass 391) Subject matter wherein the bandwidth reduction is performed by folding the higher frequencies down to fit inside a reduced frequency spectrum by sampling at a rate less than twice the highest frequency, causing the alias and baseband spectrums to overlap.

(1) Note. The Nyquist criteria states that the sampling rate should be at least twice the baseband. In sub-Nyquist systems, the sampling rate is less than the required Nyquist sampling rate.

(2) Note. The alias components, which are generated by sampling and centered on the sampling frequency, are normally placed in teeth or gaps of the video spectrum to allow

recovery of the original full band signal.

(3) Note. These systems often use comb filters (2 or 3 dimensional filters using line, field, or frame delays) to remove any signal in the gaps.