Scaling the values to specific range

Pat
2012 11 21
2 个回答
回答已采纳
2 次查看（30 天）

0 个投票

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 个评论
显示 4更早的评论 隐藏 4更早的评论

Harshit
Harshit 2012-11-21
Both [(2^13-1),(2^13-1)] are same.
Pat
Pat 2012-11-21
sorry harshit
[-(2^13-1),(2^13-1)]
Walter Roberson
Walter Roberson 2012-11-21
What limits, if any, are there on the input range of values?
I notice that all of your values, positive and negative, have 0 immediately after the decimal point. Is that characteristic? Should it be assumed that abs() of the values will be strictly less than 0.1 and that the output representation should take that into accout?
Pat
Pat 2012-11-21
acutally walter those are output after performing dwt2 on a audio signal
Walter Roberson
Walter Roberson 2012-11-21
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 2012-11-21
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

请先登录，再进行评论。

请先登录，再回答此问题。

 采纳的回答

Harshit
Harshit 2012-11-21

0 个投票

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 个评论
显示 11更早的评论 隐藏 11更早的评论

Pat
Pat 2012-11-21
I tried and i get all values as 8192 only
Harshit
Harshit 2012-11-21
Sorry pat it should be min(round(2^13*S),2^13))
Harshit
Harshit 2012-11-21
Max always be 8192 since 2^13 is always greater than s*2^13 when s<1
Pat
Pat 2012-11-21
the output for 16 bit ranged from -32768 to 32768,same way i want to do for 14 vit from -8192 to 8192,i.e sampling the signal into 14 bit
Harshit
Harshit 2012-11-21
It is. see D1=int16(S*32768) 32768=2^15 and that is why I am using 2^13. Also int16 just limit the value to 2^15 and my min is doing the same.
Harshit
Harshit 2012-11-21
Check output for your S it is not -32768 this value is achieved for S=-1,1.
Pat
Pat 2012-11-21
plz chk this
clc clear all [y,Fs,nbits] = wavread('bart.wav');
[cA,cH,cV,cD] = dwt2(y,'haar');
D1=int16(cA*32768);
min(D1) is -32768 max(D1 ) is 32767
http://www.sendspace.com/file/da23bk
Pat
Pat 2012-11-21
clc clear all [y,Fs,nbits] = wavread('bart.wav');
[cA,cH,cV,cD] = dwt2(y,'haar');
W=min(round(2^13*cA),2^13);
min(W)=-12844
max(W)=8192
is it correct harshit
Harshit
Harshit 2012-11-21
Ok finally here it is max(min(round(2^13*S),2^13),-2^13). The thing was that we didn't place a limit on negatives which I now did.
Pat
Pat 2012-11-21
THANKS LOT HARSHIT ,finally i got it but one thing i get values for
cA as -8192 to 8192;
but for cH,cV,cD i get other values such as ,-78 71,-313 321,are these also correct
Pat
Pat 2012-11-21
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 2012-11-26
I will say you to do it because fixed point operations are done similarly.

请先登录，再进行评论。

更多回答（1 个）

Walter Roberson
Walter Roberson 2012-11-21

0 个投票

Qscaled = 2^13-1;
(Your permitted range consists of exactly one value, so all numbers must scale to that one value.)

2 个评论
显示 无 隐藏 无

Pat
Pat 2012-11-21
sorry walter it is
[-(2^13-1),(2^13-1)]% a signed 14 bit
Jan
Jan 2012-11-21
编辑：Jan 2012-11-21
@Pat: Instead of adding comments, fixing this error by editing the question would be less confusing for the readers. So please fix this.

请先登录，再进行评论。

类别

在 帮助中心 和 File Exchange 中查找有关 Audio I/O and Waveform Generation 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by