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31 views

Which algorithms one can use for matrix inversion (for beamforming application MVDR/LCMV) in Fixed Point?

I have implemented beamformer(MVDR/LCMV) for speech enhancement in matlab, now I am trying to convert it to fixed point implementation. during the weight calculation step correlation matrix inversion ...
0
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1answer
31 views

scanning an image for projected points

I'm projecting a series of points onto a surface and then recording their locations in the corresponding image. However, if one goes pixel by pixel a single point may, at times, take up multiple ...
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0answers
29 views

fixed point implementation of 1/x

I am trying to use fixed point to implement the function 1/x for the integer from 1 to 2048. My plan is that I use fixed point representation for some picked integers as entries in one lookup table ...
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0answers
44 views

Fixing drift in a recursive fixed point filter

I'm implementing a 80-72-64-48 multi pass moving average filter for a embedded system in C and in fixed point. The implementation is a circular buffer where i'm keeping a running sum and calculating ...
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0answers
28 views

Orthogonality test on fixed point FFT

I have tried the following methods to test the orthogonality on Fixed point FFT implementation. FFT: Y = A*x, where A = FFT basis and x = input, Y= FFT output If the input (x) is set to A-1(A ...
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2answers
99 views

Are SOS structures better for linear phase FIR filters?

I've seen many discussions suggesting that SOS's are often/usually the preferred structure for fixed point hardware filter implementations, since they preserve conjugate pairs, etc., but I've never ...
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2answers
221 views

best implementation of a real-time, fixed-point iir filter with constant coefficients

I have implemented IIR filter in direct form, parallel form, and cascade form. The input in all the cases is a kronecker delta function. How to judge which implementation is better is in real time and ...
0
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2answers
70 views

Fixed point conversions

Have following questions about Fixed point conversion format. Suppose I want to change Fixed Point format as X1(m1,n1) (→) X2(m2,n2),m1+n1=m2+n2[Word length same], n2>n1[ Higher Fractionlength] ...
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0answers
43 views

Fixed Point queries-1

I would really appreciate if I can get answers to following Fixed point queries(part-1): Converting a real number x to fixed point fraction X(m,n) [1] says: m = ceil(log2(max[abs(xmin,xmax)+1])) ...
2
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3answers
314 views

Books/resources for implementing various mathematical functions in fixed point arithmetic for DSP purposes

I'm looking for books/resources out there that deal with, in detail, implementing mathematical functions - log/exponential/sine/cosine/inverse in fixed point arithmetic for DSP purposes. Looking for ...
2
votes
1answer
186 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
127 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 ...
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0answers
50 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
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1answer
2k 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
430 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
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1answer
238 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
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1answer
771 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
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0answers
244 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
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1answer
1k 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
74 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
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5answers
2k 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 ...
6
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5answers
2k 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 ...