Scaling the values to specific range

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Pat
Pat on 21 Nov 2012
Q=[ 0.0669
0.0383
0.0029
-0.0344
-0.0554
-0.0459
-0.0316
0.0086
0.0392
0.0650
0.0698
0.0478
0.0201
-0.0134
-0.0468
-0.0583
-0.0468
-0.0229
0.0115]
I want to scale the value of Q in range [-(2^13-1),(2^13-1)]
please help
  6 Comments
Walter Roberson
Walter Roberson on 21 Nov 2012
I can't be bothered to research dwt2() to find out what the possible theoretical output ranges are for each possible class of input data. How about if you just state the value ranges and any specific encoding instructions ?
Pat
Pat on 21 Nov 2012
walter these are coefficients from dwt2
S=[ 0.0038
0.0019
0.0105
0.0048
0.0038
-0.0105
-0.0134
-0.0191
-0.0258
-0.0229
-0.0086
-0.0076
-0.0086
-0.0010
0.0038
0.0048
0.0019
-0.0038
-0.0086
-0.0029
0.0038
0.0086
0.0096
0.0124
0.0057
0.0067
-0.0010
0.0029
0.0086
0.0057]
from this i have to sample in that range i.e in 14 bit range .
for 16 bit i have performed
D1=int16(S*32768);please tell how to perform for 14 bit

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Accepted Answer

Harshit
Harshit on 21 Nov 2012
D1=int16(S*32768) maps your any integer S*32768 outside the range to 32768 or for S>1 the output will be 32768(2^15) otherwise it will be round off to the nearest integer(You are assuming maximum non saturating input is 1 beyond this there will be saturation). You can see simply use max(round(2^13*S),2^13). Hope it will be fine.
  13 Comments
Pat
Pat on 21 Nov 2012
ok thanks a lot harshit my final question,i have performed operation on cA,if i am usind idwt2,have i to perform same operation for ch,cV,cD for effictive reconstruction,else performing on cA is enough
Harshit
Harshit on 26 Nov 2012
I will say you to do it because fixed point operations are done similarly.

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More Answers (1)

Walter Roberson
Walter Roberson on 21 Nov 2012
Qscaled = 2^13-1;
(Your permitted range consists of exactly one value, so all numbers must scale to that one value.)
  2 Comments
Pat
Pat on 21 Nov 2012
sorry walter it is
[-(2^13-1),(2^13-1)]% a signed 14 bit
Jan
Jan on 21 Nov 2012
Edited: Jan on 21 Nov 2012
@Pat: Instead of adding comments, fixing this error by editing the question would be less confusing for the readers. So please fix this.

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