quantiz (Communications Toolbox)

Produce a quantization index and a quantized output value

Syntax

index = quantiz(sig,partition);
[index,quants] = quantiz(sig,partition,codebook);
[index,quants,distor] = quantiz(sig,partition,codebook);

Description

index = quantiz(sig,partition) returns the quantization levels in the real vector signal sig using the parameter partition. partition is a real vector whose entries are in strictly ascending order. If partition has length n, then index is a column vector whose kth entry is

0 if
m if
n if

[index,quants] = quantiz(sig,partition,codebook) is the same as the syntax above, except that codebook prescribes a value for each partition in the quantization and quants contains the quantization of sig based on the quantization levels and prescribed values. codebook is a vector whose length exceeds the length of partition by one. quants is a row vector whose length is the same as the length of sig. quants is related to codebook and index by

```
quants(ii) = codebook(index(ii)+1); 
```

where ii is an integer between 1 and length(sig).

[index,quants,distor] = quantiz(sig,partition,codebook) is the same as the syntax above, except that distor estimates the mean square distortion of this quantization data set.

Examples

The command below rounds several numbers between 1 and 100 up to the nearest multiple of ten. quants contains the rounded numbers, and index tells which quantization level each number is in.

[index,quants] = quantiz([3 34 84 40 23],10:10:90,10:10:100)

index =

     0
     3
     8
     3
     2


quants =

    10    40    90    40    30

See Also
lloyds, dpcmenco, dpcmdeco

qaskenco randerr