Impact of complex limiter on BPSK BER

Started by John Sampson in comp.dsp15 years ago 18 replies

I am working on a fixed-point DSP-based coherent BPSK modem. In order to improve the computational dynamic range of the clock recovery...

I am working on a fixed-point DSP-based coherent BPSK modem. In order to improve the computational dynamic range of the clock recovery and carrier tracking algorithms, I put a complex limiter on the complex baseband. It comes after the signal has been filtered with a rectangular pulse with length equal to one bit time. What it does is compute phi=atan2(y/x) and then looks up sin(phi) and cos(...


6.3121 in fixed point?

Started by Luis Fernando in comp.dsp15 years ago 12 replies

hello i'm working with a motorola that can represent 1.15 fixed-point numbers any ideas on how can I multiply a number by 6.3121? thanks

hello i'm working with a motorola that can represent 1.15 fixed-point numbers any ideas on how can I multiply a number by 6.3121? thanks


C code for fixed point atan2

Started by Eric Meurville in comp.dsp9 years ago 28 replies

Hello, I have to implement atan2 on a dsPIC30F and would like to do that in fixed point for reasonable performance. Does someone already did...

Hello, I have to implement atan2 on a dsPIC30F and would like to do that in fixed point for reasonable performance. Does someone already did that? Thanks, -- Eric Meurville


Fixed Point DCT

Started by porterboy in comp.dsp14 years ago 1 reply

CONTEXT: I have implemented DCT's in fixed point (DCT-IV and DCT-II). Currently I allow one extra bit, each time there is an addition, to...

CONTEXT: I have implemented DCT's in fixed point (DCT-IV and DCT-II). Currently I allow one extra bit, each time there is an addition, to avoid overflow. For example for a size 64 transform there are 6 stages of decomposition in radix-2 and each stage involves addition, which means I need log2(64)= 6 extra bits to losslessly transform the worst case input. QUESTION: Is there some way of ...


Help in Fixed point toolbox for converting float to fixed

Started by Anonymous in comp.dsp14 years ago 5 replies

i, I have two floating point arrays say Signal1 = sin(2 * pi * 10 * (.1:.1:10)); Signal2 = sin(2 * pi * 5 * (.1:.1:10)); Now I want to...

i, I have two floating point arrays say Signal1 = sin(2 * pi * 10 * (.1:.1:10)); Signal2 = sin(2 * pi * 5 * (.1:.1:10)); Now I want to convolve those two signals after fixed point conversion So FixedSignal1 = fi(Signal1,1,16); FixedSignal2 = fi(Signal2,1,16); Output = conv(FixedSignal1,FixedSignal2); The above statement is giving an error ?? Error using ==> conv A and B must


TI 54x Assembler - Is it possible to move between T/ASM and A/B registers

Started by Anonymous in comp.dsp14 years ago 2 replies

Hi all, I have what should be a simple request that I can't seem to find the answer to. In TI 54x assembler, is there an instruction to...

Hi all, I have what should be a simple request that I can't seem to find the answer to. In TI 54x assembler, is there an instruction to copy a value directly from either the T or ASM registers to the A/B accumulator registers? My motivation is that fixed point math frequently requires a shift value to be calculated in the A or B accumulators (I dont believe T or ASM can do arithmetic)...


FFT Fixed Point in Matlab Code

Started by Mas Bas in comp.dsp14 years ago 8 replies

Folks, Is there any free source code for FFT Fixed Point in Matlab Code ? Thanks. Rgds, Berry

Folks, Is there any free source code for FFT Fixed Point in Matlab Code ? Thanks. Rgds, Berry


Porting LMS from floating-point to fixed-point processor

Started by Daniel in comp.dsp14 years ago 35 replies

Hello Everybody, for my diploma thesis, I have to implement a Least-Mean-Square Algorithm on a fixed-point DSP (TI 6416). The LMS was...

Hello Everybody, for my diploma thesis, I have to implement a Least-Mean-Square Algorithm on a fixed-point DSP (TI 6416). The LMS was implemented on a floating-point processor(TI 6713) earlier, so I just to the code and copied it. Of course, there are a lot of float variables in the code. When I ran the program, it workes for small FIR orders (6), but the larger the order of the filter, th...


Fixed point FFT scaling

Started by NewLine in comp.dsp14 years ago 14 replies

Hi, I am making a fixed point FFT in an FPGA. My architecture will use 1 'buttterfly' processor that will be reused in every stage. However I...

Hi, I am making a fixed point FFT in an FPGA. My architecture will use 1 'buttterfly' processor that will be reused in every stage. However I can have a different scaling in each stage. I am using a radix-2 decimation in time structure. The 'problem' is finding out the scaling to use in each stage. Note that I am not interested in keeping the 'rms' of the input and output the same, but...


fixed point modelling problem

Started by elbib00 in comp.dsp14 years ago 2 replies

hi i m trying out fixed point modelling via the 'fi' function in matlab. everything seems smooth until i tried to exponent the 'fi' object. ...

hi i m trying out fixed point modelling via the 'fi' function in matlab. everything seems smooth until i tried to exponent the 'fi' object. error msg: 'function exp is not defined for values of class embedded.fi' applying the exponential function, 'exp', is essiential for my project. anyone knows how to get ard this prob? cheers This message was sent using the Comp.DSP web int...


Blackfin 32 x 32 multiply

Started by csaudio in comp.dsp14 years ago 1 reply

The Blackfin has a 32 x 32 integer multiply that requires 5 cycles. The UG states that this minics a "C" 32 x 32 integer multiply. Is this the...

The Blackfin has a 32 x 32 integer multiply that requires 5 cycles. The UG states that this minics a "C" 32 x 32 integer multiply. Is this the low 32 bits of the 64 bit result? If so then is this not able to do signed fractional fixed point 32 x 32 multiplies? Thanks C&S Audio Labs


fixed vs floating

Started by abhi_15sep in comp.dsp14 years ago 3 replies

i had searched on internet but i am unable to find...WHY FIXED POINT PROCESSOR HAS HIGHER CLOCK SPEED THAN FLOATING POINT...

i had searched on internet but i am unable to find...WHY FIXED POINT PROCESSOR HAS HIGHER CLOCK SPEED THAN FLOATING POINT PROCESSOR? regards abhishek This message was sent using the Comp.DSP web interface on www.DSPRelated.com


Simulink: S functions

Started by Anonymous in comp.dsp14 years ago 1 reply

People, I am developing a C-MEX file (S-function) for implementing fixed point filters and testing the same using Simulink. I have 16 bit...

People, I am developing a C-MEX file (S-function) for implementing fixed point filters and testing the same using Simulink. I have 16 bit signed data in 1.15 format. I wanted to know what data format I should use (sfrac(16)/sfix(16)). Also how does one account for scaling and overflow? If you use Simulink's filter blocks, this is taken care of internally and what I think it does is to i...


Convert floating point values to fixed point?

Started by Robert Oschler in comp.dsp14 years ago 6 replies

Hello, I want to try using an fixed point based FFT routine instead of the current floating point based routine. I have a user of my software...

Hello, I want to try using an fixed point based FFT routine instead of the current floating point based routine. I have a user of my software that has a 800 Mhz VIA chipset motherboard, and the FPU on that thing is so bad, it can't crunch an audio signal in real time (i.e. - while they are talking). On non-VIA systems the computer is able to keep up in real time (it's a speech recognitio...


Scaling in fixed point filter design.

Started by Anonymous in comp.dsp14 years ago 6 replies

People, I am designing fixed point filters for processing audio signals and am faced with the following issue. I need to have the output...

People, I am designing fixed point filters for processing audio signals and am faced with the following issue. I need to have the output within a range of +0.999969 and -1 or effectively 32767 and -32768 (range of a 1.15 signed fractional number). I have two options - scaling the input or scaling the filter coefficients. I realize that scaling the input will definitely cause a reduction...


Floating and fixed point

Started by estdev in comp.dsp14 years ago 2 replies

Dear all, What always read about floating and fixed point in DSP. What is that mean? What is the different between floating and fixed points...

Dear all, What always read about floating and fixed point in DSP. What is that mean? What is the different between floating and fixed points in DSP hardware and DSP software design ? Thank you very much. Best wishes, estdev


Beginner: Integer FFT and Fixed Point FFT

Started by Karthik Ravikanti in comp.dsp14 years ago 67 replies

First things First..I am totally new to DSP...just completed an introductory course...never coded for DSP...not in C...not in Assembly..but I...

First things First..I am totally new to DSP...just completed an introductory course...never coded for DSP...not in C...not in Assembly..but I did use the built in functions in Matlab :D... I am trying to learn programming the Motorola DSP(I dont know which one :D My Prof wants me to code in C first...then code in Assembly...so the it doesn't matter). So, to start with, I was told to try ...


FFT in TI's DSP

Started by Mike in comp.dsp14 years ago 13 replies

Hello, Does anyone implement 256pt fixed point FFT on TI's DSP chip? If so, would you please let me know the model, response time and...

Hello, Does anyone implement 256pt fixed point FFT on TI's DSP chip? If so, would you please let me know the model, response time and etc? Thanks in advance, Mike


IIR with fixed-point numbers?

Started by Elektro in comp.dsp14 years ago 17 replies

What?s the best way to determine the required number of bits necessary in a fixed-point IIR-filter? To avoid overflow during calculations.

What?s the best way to determine the required number of bits necessary in a fixed-point IIR-filter? To avoid overflow during calculations.


ARM LINKS ANS DOCUMENTAION OF THE ARCHITECTURE

Started by Anonymous in comp.dsp14 years ago 1 reply

Dear All I am newbe to the ARM Processor, I dont have any Idea of ARM processor, I have to learn about the ARM processor, Please Guide me...

Dear All I am newbe to the ARM Processor, I dont have any Idea of ARM processor, I have to learn about the ARM processor, Please Guide me with the links and the documentation where i can find the materials on the arm processor. I have to port the floating pont implementaion into the fixed point implementaion in the ARM processor. So please Guide me on the above so that I...