forward and reverse coefficients

[chw19872004]

Hi all, I am a newbie here.

I am currently working on a filter project. I am required to design a filter in LabView based on the filter circuit and a list of coefficients given. (i have 512 coefficients here, so i dun think it is the 1 that i need)

I was thinking of using IIR filter to achieve this. The problem that i am facing now is i do not know how to determine the reverse coefficients and the forward coefficients input to IIR filter.

I would like to know if there is any formula or way to find these two coefficients? Is there any better way to create this filter in Labview?

I would really appreciate if anyone can help me in this. thanks thanks 😃

Regads,

Hauo Wah

[JK1]

Hai,

Try using Smoothing Filter Co-efficients.vi (signal processing>>filters>>Advanced IIR Filtering).  Is this the one you are looking for?

[Coq_Rouge]

Just take a dive into any of the IIR VIs then you will se how to constuct a IIR filter

[chw19872004]

Hi JK1 & t06afre,

Thanks for your quick reply.

My project is to design an A-curve Filter in LabView. I am supposed to do it based on the data curve given. (See attached)

JK1, i realised if i use the coefficients generator (by the way, i cant find the smoothing filter coefficients.vi. Is it because i am using labview 6.1 and this vi is only available in newer version?), i cant get the curve required. Is there any way which i can enter my data to obtain the curve that i want?

Best Regards,

HW

[chw19872004]

I came across the following sentence in another post:

"To create a frequency filter (either high-pass, low-pass, band-pass or notch), you have to use one of two methods, FIR or IIR. By using these two filters with different parameters, you are able to recreate any type of filter desirable. "

i am wondering if the parameters meant are filter structure, reverse coefficients and forward coefficients? If yes, how should i make neccessary adjustment to make the filter as closed as possible to the requirements specified?

Regards,

HW

[JK1]

Hai,

FIR or IIR filters are generic models that can be used to create other filters.

Dive into dspguru.com website to get detailed info on digital filters.  I am attaching the smothing filter co-efficients vi along with this mail.  This vi ships along with the professional development system of LabVIEW not sure about 6.1 having this VI.

The VI i have attached is converted to 8.0 version (i was able to convert up to that only!!) try converting to the version required.

Feel free to post for any queries. 

[chw19872004]

Thanks, JK1. 😃