Block error

A block error is a common type of error in certain types of digital television transmission, particularly those that use image compression. Its presence in a television image is a telltale sign that 1) the signal is broadcast digitally, as this type of error can not occur in analog transmission, and 2) that there is a significant amount of noise, as digital television is designed to tolerate a certain amount of interference. Block errors are usually detected, but not corrected, by the receiving device and are commonly displayed as empty black boxes in the television image.

Because of how television images are usually compressed, a block error in a single frame often results in black boxes in several subsequent frames. In the worst case, a few block errors per frame could render the video from a television broadcast unviewable.

Block errors are most common in digital satellite television, where bad weather or motion of the satellite dish can cause interference outside the broadcaster's control.

Block errors can occur at levels of interference where an analog transmission would be fuzzy but still viewable. Thus, block errors are a fine example of the consequences of trade offs in engineering. Although in ideal conditions, digital transmission far exceeds analog transmission in performance, below a certain threshold of signal to noise ratio, digital transmission becomes untenable.

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Block Error Rate —   [dt. Blockfehlerrate], Fehlerrate …   Universal-Lexikon

  • block error rate test/tester —    (BLERT)    A method or device used to measure the quality of the block transmission, the pattern of block transmission, and the number of block errors received. The figures obtained are used to compute the block error rate …   IT glossary of terms, acronyms and abbreviations

  • block error rate —    The number of blocks received with errors compared to those received correctly …   IT glossary of terms, acronyms and abbreviations

  • Block cipher modes of operation — This article is about cryptography. For method of operating , see modus operandi. In cryptography, modes of operation is the procedure of enabling the repeated and secure use of a block cipher under a single key.[1][2] A block cipher by itself… …   Wikipedia

  • Error detection and correction — In mathematics, computer science, telecommunication, and information theory, error detection and correction has great practical importance in maintaining data (information) integrity across noisy channels and less than reliable storage… …   Wikipedia

  • Error exponent — In information theory, the error exponent of a channel code or source code over the block length of the code is the logarithm of the error probability. For example, if the probability of error of a decoder drops as e – n α, where n is the block… …   Wikipedia

  • Block matching — Saltar a navegación, búsqueda Algoritmo utilizado en la estimación de movimiento, consistente en la eliminación de redundancia temporal entre dos o más fotogramas sucesivos. Se ha convertido en una técnica fundamental en la mayoría de los… …   Wikipedia Español

  • Error analysis — is the study of kind and quantity of error that occurs, particularly in the fields of applied mathematics (particularly numerical analysis), applied linguistics and statistics. Error analysis in numerical modelling In numerical simulation or… …   Wikipedia

  • Block Truncation Coding — Block Truncation Coding, or BTC, is a type of lossy image compression technique for greyscale images. It divides the original images into blocks and then uses a quantiser to reduce the number of grey levels in each block whilst maintaining the… …   Wikipedia

  • Block code — In computer science, a block code is a type of channel coding. It adds redundancy to a message so that, at the receiver, one can decode with minimal (theoretically zero) errors, provided that the information rate (amount of transported… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.