Asked by Yang
on 28 Mar 2013

masters~ now I'm facing a problem that i have to convert some signed floating point numbers to binary, like -4.182068393394077e-04, or 1.3489.

do anybody have some idea or advices?

thanks

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Answer by Walter Roberson
on 28 Mar 2013

dec2bin(typecast(TheNumber, 'uint16'), 16) - '0'

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Yang
on 31 Mar 2013

I am hoping for a 1*N vector or N*1, both okey. if i could be, i will convinient for me to plug it in the frame which i use to input the channel encoder

Walter Roberson
on 31 Mar 2013

You need binary for the channel encoder. That is

dec2bin(typecast(TheNumber, 'uint16'), 16) - '0'

You can reshape() that to vector form. Just be sure to reshape() it back before using bin2dec() to convert the binary to numeric form.

Yang
on 1 Apr 2013

i would try this tonight, thanks

Answer by Jan Simon
on 28 Mar 2013

What exactly is a "binary stream"? It could be a vector of doubles, which contains only ones and zeros. Of a vector of type LOGICAL, or UINT8. Or remember, that all numbers are stored in binary format on a computer, so perhaps this is enough already:

x = pi; x_bin = typecast(x, 'uint8')

Yang
on 28 Mar 2013

thank you so much. the friend upside gave me a code so i convert a vector of floating point to a vector which only ones and zeros. what could i do to convert it back~

Yang
on 28 Mar 2013

couas i want to convert a celp parameter vector into binary stream so that i could input it to a Turbo encoder to do some tests for my graduation design. is that clear about "binary stream"?

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## 5 Comments

## Walter Roberson (view profile)

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/68896#comment_139445

MATLAB does not have any 16 bit floating point representation -- only 32 bit and 64 bit.

## Yang (view profile)

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/68896#comment_139478

please fogive my english and pleas tell me what the type like -4.1xxxxxe-04 called in english. is it called signed 16-bit floating point number?

## Jan Simon (view profile)

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/68896#comment_139536

It is not a question of you English, but it is currently not clear, what you mean by "16-bit floating point" type.

## Yang (view profile)

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/68896#comment_139548

i don't know what it called in english. what is the type of the number -4.4367e-04 called in english? floating poiont? signed?

## Walter Roberson (view profile)

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/68896#comment_139595

I have never encountered an unsigned floating point representation. I

haveencountered unsigned fixed point representations.The closest you could get to -4.4367e-04 with a signed floating point representation would be to use a scheme with 1 sign bit, 5 exponent bits, 1 "hidden bit", and 10 bits of mantissa. That would allow you to express -(836/1024 + 1) / 2^12, or approximately -4.4346E-04. Notice this only gives you a few decimal places.

5 digits of accuracy requires 16 or 17 bits

andthe bits for the exponent. 1 sign bit, 5 bits of exponent, 1 hidden bit, 15 bits of mantissa = 21 bits of representation.