All Questions
Tagged with fixed-point infinite-impulse-response
17 questions
0
votes
3
answers
139
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Fixed point number scheme IIR filter with ADC
I am a student working with digital circuits. I just started a term project with someone else working on an ADC. I need to design a IIR filter in verilog.
If the output of an ADC represents 1V by ...
0
votes
1
answer
447
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Fixed point implementation of IIR filter
I am trying to implement an IIR filter followed by downsampler with the following specifications:
fs=18000,order=8,3db freq=[500 1000],downsampling factor=6.
...
- 325
2
votes
1
answer
398
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Fixed-Point Filter Design: Where comes the DC-Gain difference between the bode plot and the step response from?
Introduction: What I wanted to achieve
I am currently trying to implement a digital fixed-point filter on a STM32-Microcontroller by using the ARM CMSIS-DSP Library Link to reference manual.
The ...
- 125
0
votes
1
answer
733
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Modelling and testing fixed point IIR filter with freeware tools
I understand from this other question that prior to implementing a fixed point IIR filter on a particular microcontroller target it's best to create a model using a DSP tool and compare the output to ...
- 143
4
votes
1
answer
588
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Wrong result when realizing fixed-point biquad IIR filter
I'm implementing a fixed-point direct form I biquad filter with Q1.15 precision. I use fraction saving to improve quantization error. However, my function gives me the different results compared by ...
- 527
5
votes
3
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1k
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Why does the Direct form I become our first choice for fixed-point implementation?
I heard that the Direct form II transposed is better for floating-point and the Direct form I is better for fixed-point. Is it true?
I understand that DF2 and DF1T should never be used in fixed-point ...
- 3,263
2
votes
1
answer
265
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How to improve accuracy while converting floating point coefficients to fixed point in the case of an all pole IIR filter
I am having an all pole IIR filter of order 5 with floating point filter coefficients
...
- 325
3
votes
6
answers
3k
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Single pole IIR filter, fixed point design
We want to do a fixed point implementation of the single pole IIR filter:
$y[n] = a\cdot x[n] + (1 - a)\cdot y[n-1] \quad ;\qquad 0<a<1$
What are the main design considerations to think about ?...
- 41
1
vote
1
answer
393
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Methods to evaluate the quality of an IIR Filter fixed-point implementation
I'm implementing a scattered look-ahead IIR filter in Matlab/VHDL, basically I convert an order-2 IIR filter into an order-4 IIR in order to take advantage of the pipelining of an FPGA. (reference ...
- 3,797
0
votes
2
answers
485
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Floating point to fixed point in C
I've been trying to make a digital filter.
I've used the following transfer function to get my digital coefficients
https://gyazo.com/00195ef119f0b2ff93fa5855715abdc9
Which i've then transfered to ...
1
vote
1
answer
300
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VHDL fixed point implementation of IIR filter
I have a filter described by the following transfer function H(z):
$$H(z) = \frac{156 - 156z^{-2}}{16384 - 32443z^{-1}+16073z^{-2}}$$
How will this be implemented with the first term in the ...
- 113
1
vote
0
answers
367
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Fixed point Error Spectrum Shaping (noise shaping) for biquads
Based on that article and all the resources on the internet that advise the use of noise shaping for fixed-point filter implementations, I tried to make a few simulations on Matlab for the biquad I'm ...
- 754
1
vote
0
answers
513
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Converting floating point IIR to fixed point arithmetic, given its difference equation
Is there some general way to perform the task given in the question? I have a filter given as follows:
...
- 330
2
votes
2
answers
1k
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Trouble with fixed-point arithmetic 2nd order IIR implementation in c
DSP newcomer here!
I am tinkering around with a TI DSP and am trying to implement a second order IIR filter in C. Input is 16 bit 2's complement, as is the output, the accumulator is 32 bit wide.
I ...
1
vote
1
answer
174
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Implementation of IIR Filter in dsPIC 33EP - Q15
I am implementing an IIR controller in dsPIC 33EP (16-bit, fixed-point, two's complement, wrap-around, 40-bit accumulator, 32-bit multiply, 12-bit ADC) and I am using cascaded, Direct Form I second ...
- 33
3
votes
1
answer
310
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Why is the frequency response different based on the amplitude of the impulse I feed into the filter?
I am working on a 2-pole IIR high-pass filter. The filter is fixed point and it is causing me some issues. I believe I'm just misunderstanding something. I am implementing everything in Octave for ...
- 31
10
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2
answers
8k
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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 ...
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