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98 Threads found on edaboard.com: Cic And

the way of design CIC filter

cic really is an implementation. The filter it describes is itself not that good. it is moving average to then Nth power. Huge amount of delay and generally poor filtering characteristics. But the implementation with fixed point math is insanely simple. You can use filter/conv/filtfilt to perform a cic filter in matlab. The performance (...)

CIC filter and simulink simulation problem

i am trying to design a decimator for sigma delta converter . my decimation factor is 48. from material i found i decided on a cic filter for first stage (decimation of 24) and a cic filter as second(decimation of 2). sampling freq =3840 KHZ Fin = fin = 0-80khz stop band attenuation = 100 dB About the SINK filter (...)

decimator filter output wordlenght problem

Hi, I have designed a decimator filter for a 8 bit sigma-delta ad convertor. I use one cic, one halfband and one FIR filter. The output of the decimator is 38 bits. In order to achieve lower power consumption I dont want to cut all 30 LSB bits at the end. Instead of this I want to reduce the output for each stage. For example cutting 5 bits (...)

Decimator Design for sigma delta converter

i am trying to design a decimator for sigma delta converter for audio. my decimation factor is 128. from material i found i decided on a cic filter for first stage (decimation of 64) and a half band FIR as second. so the cic filter has 3 parameters - decimation factor , no of delay elements and the (...)

CIC filter wordlength and simulink simulation problem

Hi, I want to design a cic filter which has a decimation ratio of 32, I need 10 bits at the output, and my input is 2 bits, I want 3 stages and differential delay is 1 so according to Hogenauer's paper wordlength is N*log(RM)+Bin -1=3*log(32)+2=16 bits, however I want 10 bits at the output, and again according to (...)

Usually, you'll want to utilize the delay register to achieve pipeline action and connect the next stage at it's output rather than at the adder directly. A separate pipeline register may be used, if the cic integrator clock is as divided system clock.

Question about CIC output spectrum and alias

Hi all, Lst say a input signal IP with 0~200KHz bw is sampled at fs=16MHz (lets call it X), then pass through a 1st order cic decimation filter (R=8, M=1) to get 2MHz output (lets call it Y). Let define Δf as shifting the signal to center at f, so X = IPΔ0 + IPΔ16M + IPΔ32M ... and sinc is the sinc function without al

Sigma Delta - Two stage decimation filter

I am designing a two stage filter to do decimation at the output of a Sigma Delta modulator. Here is the spec - Sampling frequency - Fs - 1.4MHz Decimation factor - D - 100 Output resolution - 13 bits. The filter, and the modulator is reset every 100 clock cycles. To accomplish this, I used a 5 stage cic filter to decimate by 20 for the

sinc3 vs cic: guess it is a trade-off between complexity and performance. More complex -> better image removal and vice versa. slope to magnitude: all these filters do are just averaging. More complex filters given you average of the averages many times over. Now finding the average is just integration, if you ignore the scaling by (...)

I am working on a Sigma Delta ADC project, and need to decide the bit-width of the digital filter. My filter has 4 stages, the first is cic and the bit width is 29 bits according to the OSR. My final filter output is only 24 bits. So this means the other 3 FIR filters need to reduce 5 bits in total. If my input is 4-bits signed (...)

when using the cic filter as decimation filter,is a compesation filter needed? the basic cic structure is composed of two section,integrator section and comb section.I found that the response of integrators for dc input is without bound. so does that imply we can not use the structure in practice?

matlab coded needed for filter decimation

My IF is 5Mhz. I need to reduce my sampling frequency 409.8Mhz to 20.48 Mhz by using FIR lowpass filter, so i am decimating it in 2 stages , first time i am using cic filter and decimation factor 5 then i will get the new sampling frequency 81.9 which is given to half band filter by decimating factor 4 then we will obtain finally (...)

Does the order of the CICCOMP matter in the matlab?

Hi,all I am in a project of Sigma-Delta ADC. But I get in trouble when I design the digital filter in the MATLAB. The filter consists of a cic, a cicCOMP and two halfband. When cic is followed by the cicCOMP and then the twe halfbands, the (...)

What's wrong in CIC filter spectrum?

I have designed sigma-delta followed by cic decimator , and run FFT at cic filter output. The result is shown in attachment file. what's wrong in the spectrum?? thank you! ------------------------- spec: fin=1.5625 Hz fs=51200 Hz decimator ration=256

What's wrong in CIC filter spectrum?

I have designed sigma-delta followed by cic decimator , and run FFT at cic filter output. The result is shown in attachment file. what's wrong in the spectrum?? thank you! ------------------------- spec: fin=1.5625 Hz fs=51200 Hz decimator ration=256

Can one show me cic filter(cascade of integrator comb filter) MATLAB code? I want to design a Sinc^2 comb filter followed by sigma-delta ADC. It is 1-bit input , 16-bit output decimation filter. How can I bulit and setting a cic SIMULINK model? pls help me, thank you!

Low Latency Decimator Filter

Hello everyone, Can anyone let me know what is the best decimator filter structure to achieve low latency compare to the tradisional cic filter with cascade Comb and integrator section? Thanks.

Step Response for cascaded filter & CIC filter

Hi Sir/Madam, I had done an evaluation using 1. cic filter with decimator factor of 128 2. cic filter with decimator factor of 32 and 2 half band filter. I am seeing the time needed for the filter to get stable is longer for option 2 above. What i did is i run a step response for filter option 1 (...)

Signal distorted after CIC filter

Hi Sir/Madam, Can anyone here let me know why the amplitude of the signal get distorted after it go through the cic filter? Is is due to the passband of the cic filter is not flat? I had try to cascade the cic filter with compensator filter and i see the passband quite flat (+/- (...)

design CIC and compansation FIR filters

you can download some paper from IEEE which can help you much. An economical class of digital filters for decimation and interpolation.pdf This paper is a good paper and it introduces cic filter first.