Third part information

Third party information is not necessairly false.

I once worked with a person who was very talented. He had noting good to say about the Orcad program that designed custom logic. Even though I have never used this program, I think that his experience is valid.

I once woked with a person who formerly worked at a company that made a microwave filter program that is now not frequently used. He told me that the major complaint from users was the obscure users interface. He also told me that the owner of the company knew this and refused to improve the interface. I have never used this program, but the above information is not false because of that.

hello freinds!
Parfil and Elliptic are updated now ! (02/17/2003)
http://www.waveconsoft.com/
let us look at newest versions Parfil v4.4 and Elliptic v4.3 .
i hope all defects are eliminated.
they had a time.
best regards.
u_f_o

As there have been some interest in a simple program for designing interdigital bandpass filters, I started to search my archives and found an article in Ham Radio Magazine january 1985 by Jerry Hinshaw "Computer-Aided Interdigital Bandpass Filter Design" The article claims a reproducible customized design in the 0.4-5 GHz frequency range. I have personally tried it and it gave excellent results on a 550 MHz 6 pole filter with just 3 MHz bw!

You can use any old DOS-computer to run, just like the Good Old Days :D


The program is written in simple Q-Basic with no graphics but still have 200+ lines of code. I tried to make a scan from my old photo-copy and I think it is possible to read it, file size 160 kb. I have really tried to find the program in electronic format with no luck.

The complete article is 12 pages with several pictures and test-run of the program. I can do copyy a complete file but please PM me, the size will be several MB!

Maybe someone with too much spare time can hack it down? Or isn't HR available as PDF on CD Rom?

Cheers
/WD

Dear WebDog
Can you email the complete article "Computer-Aided Interdigital Bandpass Filter Design" to me?
My email is microwaveempire@hotmail.com.
Thanks!

Microwaveboy,
check your e-mail.... it is a scanned picture of a programs listing.
200+ lines of basic code! If you manage to type it all, plz post it here :D

I have not an electronic version of the article, sorry. Will try to do a pdf but the quality of my copy is so poor that it is almost impossible to ocr so it will be gif-pictures i.e. large stuff.


/wd

webdog.
I have already get it. Thanks you for much

Microwaveboy (and a few others)
since you begged so nicely I decided to create a pdf-file with the complete article from Ham Radio January 1985. Please understand my orginal was a copy from a copy, but I beleive the result is readable....

Feel free to ask if you have trouble reading. :o

Cheers
/WD

Hello people.
Sorry to have come a little bit late to the discussion.
But I would like to leave here my small contribution.
The program that you were discussing, about this great article from Ham people is still available online thanks to the radio amateur wa4dsy.
This program was converted from Basic to c and is available in the following link( as cgi and also source code):

http://www.wa4dsy.net/cgi-bin/idbpf

S.

Check this pls
http://www.rfshop.com.au/page7.htm

Hey,I introduce you to use WASP-NET for waveguide filter design. ,which is a very professional tool based on Moment-Method,FEM and mainly on mode matching method.

Can anyone tell me what can introduce a spurious in the cavity components?

Thanks in advance.

Lupin

i am assuming that you are not speaking to the recuring band, if not then, i have to ask how are your resonators attached, are they machined or screwed down,
you must have a secure fit to the housing or i think this may cause this, if you could detail a little more i could ellaborate more

I am making a general reasoning... given a cavity filter and an input signal without any spurious.. can I have an output (filtered) signal with spurious.. if so, what can be the reason for a general cavity filter?

Otherwise, if the input signal has a spurious.. what can I expect?A shift? If so why?

Thanks in advance.

Lupin

I am not positive, but , i would have to say no, i filter can distort a signal, of course, in various manors, but it will not introduce any components not already present, a filter can shift the phase of course,

so I would have to say, no spurious would be added, what would happen is that it would pass frequencies it is not supposed to at most

Now there are other much more expierienced filter engineers out there that may
know more than me and I welcome any input from them

thanks

who is the first persion of coaxial filter

Try FILPRO, it can simulate and synthetise many kind of filters:
cross and direct coupled, combline, interdigidal, iris coupled, evanescent ecc...

http://www.eee.metu.edu.tr/~nyil/filpro.html