## Forums Search for: Fixed Point

## Re: Theoretically Highest Quality of PCM Audio

> > If I am given a 16-bit fixed-point number of uniform quantization, I > can surely say that the maximum theoritic dynamic range I can get...

> > If I am given a 16-bit fixed-point number of uniform quantization, I > can surely say that the maximum theoritic dynamic range I can get is > 96.329 dB Minor quibble... 96 dB is 6 dB per bit for 16 bits...the max signal is really +-32767 or +-15 bits, right? so its 90dB....

## Re: Theoretically Highest Quality of PCM Audio

In article 20031121215550.28390.00000721@mb-m14.aol.com, BobGardner at bobgardner@aol.com wrote on 11/21/2003 21:55: > > > > If I am given...

In article 20031121215550.28390.00000721@mb-m14.aol.com, BobGardner at bobgardner@aol.com wrote on 11/21/2003 21:55: > > > > If I am given a 16-bit fixed-point number of uniform quantization, I > > can surely say that the maximum theoritic dynamic range I can get is > > 96.329 dB > > Minor quibble... 96 dB is 6 dB per bit for 16 bits...the max signal is really > +-32767 or +-15 bits, righ

## Re: Theoretically Highest Quality of PCM Audio

BobGardner wrote: > > > > > If I am given a 16-bit fixed-point number of uniform quantization, I > > can surely say that the maximum...

BobGardner wrote: > > > > > If I am given a 16-bit fixed-point number of uniform quantization, I > > can surely say that the maximum theoritic dynamic range I can get is > > 96.329 dB > > Minor quibble... 96 dB is 6 dB per bit for 16 bits...the max signal is really > +-32767 or +-15 bits, right? so its 90dB.... Ah, but the largest signal swing is {32767,-32768} and the smallest is {

## fixed point implementation

inHi, i want to implement the equation p3 = p3*0.5/cos(3*PI/8); into 16bit processor, where p3 is a 16 bit value; any pointers as to...

Hi, i want to implement the equation p3 = p3*0.5/cos(3*PI/8); into 16bit processor, where p3 is a 16 bit value; any pointers as to how to go about it -vijay

## LMS fixed point implementation

inHi everyone! I need a fixed point implementation for the LMS algorithm;I have to implement it on a TI dsp board (c6711 or a c5000); can anyone...

Hi everyone! I need a fixed point implementation for the LMS algorithm;I have to implement it on a TI dsp board (c6711 or a c5000); can anyone suggest me where I can find this code? thank you guys! f

## rounding errors : fixed point precision

inI know that bits precision required for an IIR filter is proportional to the number of IRR stages. I learnt this aftermaking a 9 stage IIR using...

I know that bits precision required for an IIR filter is proportional to the number of IRR stages. I learnt this aftermaking a 9 stage IIR using doubles years ago, only the 2nd and third order ones worked correctly. Anything more went to the rails (generally), due to overflows. I also used binary scaling conventions when I worked in simulation in assembler many years ago. I am very i...

## simple FIR on fixed point ADSP2191

inHi, I have a problem with implementing filter on my Ez-kit. There is AD1885 codec. I don't know, how to convert samples form codec to...

Hi, I have a problem with implementing filter on my Ez-kit. There is AD1885 codec. I don't know, how to convert samples form codec to filtering them. I have a function: void process_samples(void) { //filtering algorithm } and filter coeffincients in array: float coff[SIZE] which is called from interrupt routine. I have to mulpitply samples (16 bit from codec) by filter co...

## Extended Precision Floating vs Fixed Point - Sharc

inThere have been several papers comparing filter topologies and filter noise performance. There have also been several papers comparing fixed...

There have been several papers comparing filter topologies and filter noise performance. There have also been several papers comparing fixed point to floating point processing. Has anyone examined Extended Floating Point (32 bit mantissa) versus 32 bit fixed point? Both options are available with a Sharc. FIR case: Fixed point should work very well since you have an 80 bit accumula...

## References for fixed point bandpass

inHi All - First off, this seems like a great group - a lot of expertise floating around out there. Hopefully someone can point me in the...

Hi All - First off, this seems like a great group - a lot of expertise floating around out there. Hopefully someone can point me in the right direction... I am new to digital filter design and need to implement a bandpass filter on a fixed point (ARM7) processor. Searching for info I have found a lot of theory, but no actual source code that I could use as a reference. I downloaded S...

## matrix inversion

inWhere I can find an example of generic matrix inversion algorithm implemented in fixed point computation (16 or 32 bits). Please...

Where I can find an example of generic matrix inversion algorithm implemented in fixed point computation (16 or 32 bits). Please help. Regards John

## How do I multiply using Qformat?

inHi, I am totally new to Q formats, and need to do the following: Multiply a unsigned 16bith number by a decimal number < 1. For...

Hi, I am totally new to Q formats, and need to do the following: Multiply a unsigned 16bith number by a decimal number < 1. For example: 30,000 * .378 = 11,340 How do I do this in a 16 bit fixed point uP with hardware multiplier The uP has the capable of doing 16x16 signed and unsigned multiplication resulting in a 32bit number. 1. How do I convert a decimal number (0.378 fo

## Memory requirements for a high amount of filters

inHi all, I am working on the first part of the implementation of a 3D sound system in real time and I need to choose a DSP processor. So far...

Hi all, I am working on the first part of the implementation of a 3D sound system in real time and I need to choose a DSP processor. So far I've checked that a 16 bit wordlength and fixed point meet my requirements. The situation is that I need to store almost 12000 fir filters, of 128th length each, as a program data (these filters correspond to head related impulse responses with a ...

## Which is better Fixed Point Presentation!

inHi, For a given DSP block say for FFT, Which fixed point presentation (interpretation) would give better results for same input...

Hi, For a given DSP block say for FFT, Which fixed point presentation (interpretation) would give better results for same input data: (1.)Signed A(9,6) presentation as per Randy Yates's Fixed point article (total 16 bits: 9 bits for integer and 6 bits for fractional part) Or (2.) Signed A(0,15) presentation (Total 16 bits: No bits for integer and 15 bits for fractional part). The ob...

## Which DSP Kit?

inHi, I'm a bit newbie to DSP architectures, so I might need some help for choosing the rigt starter kit. I'm looking for a kit with at least...

Hi, I'm a bit newbie to DSP architectures, so I might need some help for choosing the rigt starter kit. I'm looking for a kit with at least 2 ADCs and 2 DACs, with about 16 bit resolution, from where the data should be transceived to a PC, probably through an USB interface. I wan't access to the data- and addressbusses for further expansions and I think 16bit fixed-point processors mi...

## fixed-point real FFT for embedded

inHi ! I'm working on real-time speech recongnition application for embedded systems (with ARM compatible processor). I'm looking for a very...

Hi ! I'm working on real-time speech recongnition application for embedded systems (with ARM compatible processor). I'm looking for a very fast (for real-time) real FFT fixed-point version, with 16-32 bit input percision, up to 512 array-size. I found fftw to be one of the fastest, but no fixed-point version :( help would be very appreciated. Regards, Shlomi

## 2D correlation in Q15 fixed-point format

inI am trying to use a TI C6x IMGLIB routine to low-pass filter an image. This routine expects the input parameters to be in Q15 format which I...

I am trying to use a TI C6x IMGLIB routine to low-pass filter an image. This routine expects the input parameters to be in Q15 format which I must not understand correctly, and would like some assistance with. Ok, so my 3x3 kernel (in floating point form) is quite simple, merely: 1/9 1/9 1/9 1/9 1/9 1/9 1/9 1/9 1/9 To convert to Q15 format, I 1st need to ensure that the coeffs are ...

## Fixed point FFT

inHi all, Can anyone suggest me from where can I get a 1024 point fixed point real FFT C code? Thanks, SB

Hi all, Can anyone suggest me from where can I get a 1024 point fixed point real FFT C code? Thanks, SB

## Scale data before or after IFFT?

inHello, I am working on a self-study project and try to implement a DMT transmitter in VHDL. This is the first time I am dealing...

Hello, I am working on a self-study project and try to implement a DMT transmitter in VHDL. This is the first time I am dealing with fixed-point implementation of a DSP algorithm. One of the blocks is an IFFT which outputs the time domain signal. At the end this signal is passed to an ADC, which has at the most a precision of 16-bit. My question is now whether I should scale my data at t...

## Noise and Signal Subspace

inI have a file with the values associated to the electric field for 32 different frequencies at a fixed point. Due to the RootMUSIC...

I have a file with the values associated to the electric field for 32 different frequencies at a fixed point. Due to the RootMUSIC requierements, white gaussian noise is added to original vector, obtaining the noisy_matrix. After that I calculate the covariance matrix and then I get its eigenvalues. The problem is that I don?t see any meaningful difference between eigenvalues that let me id...

## Fixed point logarithm to base 2

inHi all, I have to convert 16 bit numbers to their scaled logaritm in base 2, basically 256*log2(). I am trying look-up-table approach....

Hi all, I have to convert 16 bit numbers to their scaled logaritm in base 2, basically 256*log2(). I am trying look-up-table approach. The constraint is that the error should be less then 0.01dB. Can anyone suggest how to construct a (smallest size) look-up-table and how to calculate the logarithm? Thanks, Sumeer.