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1
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1answer
109 views

inverse Fixed point number (number^-1) [closed]

Could someone please provide a method for inverting random fixed point numbers. I have as an input both positive and negative floating point numbers that should be converted into fixed point and then ...
0
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0answers
80 views

How to Prevent overflow/saturation in fixed point implementation of Fast Data Projection Algorithm

I am trying to implement an algorithm in real-time on a Fixed point DSP (The Blackfin from Analog Devices). The algorithm does a lot of stuff, but in the middle it performs an algorithm called "Fast ...
1
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0answers
31 views

DSP implementation recommended bibliography (good books-material related to fixed/floating point-optimization) [closed]

I am doing my first steps in embedded systems and there is a big deal of fixed point code and of course DSP optimized code.I would like please if possible to recommend any book/material related to ...
3
votes
1answer
1k views

Understanding Q formats

I have some misunderstandings with Q format. Please help me in understanding this. If I say Q8 [unsigned] then there will be 8 fractional bits. Is it ? How can I represent a 1 and 1.5 in this case. ...
4
votes
1answer
285 views

Fixed-point and ARM CMSIS-DSP FIR filters

I am using Q1.15 fixed-point values to represent a 12-bit signed integer value. I was wondering if it matters if I use the 11 MSB or LSB of the fractional part to represent my 11 magnitude bits? Only ...
3
votes
1answer
154 views

conversion of adc output to fixed point format

I want to convert the 2s complement, 16-bit output from an ADC into a generic fixed point format, Qm.n, where m is the no. of integer bits and n is the no. of fraction bits. Any hints/procedure to do ...
4
votes
1answer
469 views

Converting floating point number to Q-notation fixed point number in C/Java?

I am trying to convert from a floating point number to a Q-notation signed 16-bit fixed point number (e.g. Q15). How can this be done in C or Java? I searched online but could not find any available ...
4
votes
0answers
184 views

derivation of fixed-point atan2 with self normalization

I'm trying to understand the math behind http://dspguru.com/dsp/tricks/fixed-point-atan2-with-self-normalization which describes a self-normalizing fixed-point version of atan2(). In particular, ...
6
votes
1answer
682 views

Fixed point multiplication with negative numbers

I am stumped on a simple problem. Let's say I have two 4 bit numbers in Q0.3 format. One sign bit and three fractional bits. So I can represent $-1$ through to $0.875$. Let's now say I wish to do ...
1
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0answers
69 views

Word-length optimization of a fixed point chain of multipliers

Let's suppose a chain of 6 multipliers: $b = a_1*a_2*a_3*a_4*a_5*a_6*a_7$, where $b$ is the output, and $a_i$ the inputs with 16 bits. How can I optimize the word lengths of the output of each ...
7
votes
5answers
1k views

When to consider double (64 bit) floating point for Audio

When synthesizing and processing audio on modern processors, when would one consider using something other than single precision (32 bit) floating point? Obviously, the audio coming in and going out ...
5
votes
5answers
1k views

Relative merits of fixed point vs floating point computation?

I have a digital signal processing system that operates on a fast x86 machine using double precision floating point numbers. It occurred to me that I am not really using the huge dynamic range of the ...