Converting 27 bit signed binary to decimal

I have a textfile with 1024 lines, each line containing a 27 bit signed binary number. I need to convert the data in this textfile to decimal. I know how to convert signed binary of length 16, but I'm not sure how to convert 27 bit since the function uint16 does not apply to 27 bit numbers. Does anyone know how to convert 27 bit signed binary numbers into decimal? Thank you very much

2 Comments

What exactly is in the text file? Can you give a short example? Is it character data with '0' and '1', or something else?
Hey James, I've attached the textfile here

Sign in to comment.

Answers (1)

Your input file does not have 27 bit signed binary numbers: it has 32 bit signed binary numbers. 22 bits of the range are significant, but because they are stored as 32 bit you can read them as 32 bit.
fid = fopen('output_real.txt', 'rt');
datacell = textscan(fid, '%s');
fclose(fid);
values = typecast(uint32(bin2dec(char(datacell{1}))),'int32');

2 Comments

Hey Walter, You are right, I actually uploaded the text file after I adjusted it so that I could use uint32. So basically originally the textfile did have 27 bit signed numbers, then I recreated it to have 32 so I could use the method you showed. I'm still curious though, do you know how you would do the conversion if it did in fact just have 27 bit numbers? Thanks!
fid = fopen('output_really_real_not_that_fake_32bit_stuff.txt', 'rt');
datacell = textscan(fid, '%s');
fclose(fid);
temp = char(datacell{1}));
temp = [repmat(temp(:,1),1,5), temp]; %sign extend
values = typecast(uint32(bin2dec(temp)), 'int32');

Sign in to comment.

Categories

Asked:

on 5 Jan 2018

Commented:

on 5 Jan 2018

Community Treasure Hunt

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

Start Hunting!