In a uniform quantization the distortion or noise does not depend on the sample amplitude. Therefore, when the amplitude is lower the influence of the error or quantization noise is greater. The situation is critical for signals whose analogical amplitude is near the one of a quantification interval.
In order to solve this problem there arr two solutions: - To increase the quantization intervals - if there are more intervals the errors or noise will be less but we need more binary numbers to quantify a sample and therefore we end up needing more bandwidth to transmit it.
A finite number of intervals are used. Each one does not have the same width. So, they are not uniform. The width of intervals at low level is shorter than the width at high levels which are greater. This way, it is like weak signals have a high number of quantization levels, reducing the distortion or noise. The strong signals on the other hand have a worse distorsion or noise behaviour than the corresponding to a uniform quantifization, but still good enough.
Therefore, what we can do is to use a not uniform quantization by means of a codec compressor-decompressor and then a uniform quantization as you can see in the following image:. Encoding Law The not uniform quantization process follows a certain feature called encoding law. There are two types of encoding laws: continuous and segmented. In continuous encoding laws, the quantization intervals have different width, growing from small values, corresponding to low level signals, to greater values, corresponding to high level signals.
In segmented encoding laws, the operation range is divided into a finite number of groups. An A- law algorithm is a standard companding algorithm, used in European 8-bit PCM digital communications systems to optimize, i. Vivencio Niedermeyr Pundit. What is companding in communication? Companding refers to a technique for compressing and then expanding or decompressing an analog or digital signal.
It is a combination of the words "compressing" and "expanding. Data is compressed before being transmitted. Faraji Bourdon Pundit. What do you mean by law? Definition of law is a rule of conduct developed by the government or society over a certain territory. Law follows certain practices and customs in order to deal with crime, business, social relationships, property, finance, etc.
The Law is controlled and enforced by the controlling authority. Margarito Johanns Teacher. How many codecs are there? Codecs are compression technologies and have two components, an encoder to compress the files, and a decoder to decompress. There are two kinds of codecs ; lossless, and lossy. Ask A Question. Co-authors: Updated On: 9th April, Views: 1, Similar Asks. There are two varieties of this Codec, namely U-law and A-Law. U-law is typically utilised within North America and Japan, whilst A-law is typically used by the rest of the world.
This Codec is supported by most VoIP providers. One consideration to make before implementing the G. Therefore, you will find many VoIP phones that are only able to handle one call at a time due to the processing power required to deal with G. The G.
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