BANDPASS FILTER 200MHZ BANDWIDTH

[chicobulilit]

anyone could help me build a bandpass filter with atmost 200Mhz bandwidth

the frequency is that will be passed is from.. 512Mhz to 704Mhz

hope you can help me asap

i was thinking of using op amp... kaso 10Mhz lang sila nagooperate... meron bang 200Mhz above???

kung RC naman... sandamak2 na resistors and caps need ko... not to mention of the amplifier.. kasi for sure with the capacitance... may attenuation un.... eh required is no attenuation at all...

looking forward to your answers... T.T

[rdpzycho]

para saan ba 'to? kapag ganyang frequency na, LC filters for low Q, tapos Cavity, SAW, at Stripline filters naman for high Q. it's not a very simple task to design one. search for combline filters or interdigital filters, medyo madali i-fabricate 'yan sa PCB, 'yung cavity naman, pwede sa copper tubes.

[chicobulilit]

para saan ba 'to? kapag ganyang frequency na, LC filters for low Q, tapos Cavity, SAW, at Stripline filters naman for high Q. it's not a very simple task to design one. search for combline filters or interdigital filters, medyo madali i-fabricate 'yan sa PCB, 'yung cavity naman, pwede sa copper tubes.

yup alam ko po un.... may mga kagrupo naman po akasi ako.. and im trying to find out other ways... pero i'll rely on what you said as of the moment..... uhm.... kasi naisip na din po namin ung sa cavity.... pero meron ba nabibilli na ganun sa raon, e-gizmo?? and if not... dun na lang po ako sa PCB fab... mejo may alam din naman po kasi ako.. im using ALTIUM kasi... pero basics lang ang alam ko dun simple schem to pcb layouts lang... this is a prototype na pinapagawa po sa amin....

so PCB FABrication.... my professor mentioned this method nung napagkwentuhan ung project pero hindi pa din kasi sakin gaano kalinaw ung proto namin nun kaya mejo nadisregard ko xa..

[rdpzycho]

saan gagamitin at paano niyo ite-test kung tama?

rfdesign.com/mag/combline.pdf

mahirap maghanap niyang cavity filter dahil di naman siya common item, sa mga RF equipments lang siya makikita. kung may mabibili ka man, pre-cut and tuned siya sa common frequency bands na ginagamit like GSM.

[chicobulilit]

its a do or die project nga..pero exepmtion sa final exam ang kapalit once we do this right or even close to right... nung una nga 6mhz BW ung nirequire nya eh.. so sandamak2 na RC ckts ginawa namin tapos kinascade... ang mali namin is walang amp kaya may attenuation... so para daw mas madali ngaun nilakihan na nya ung BW..... actually its not excalty 200Mhz... kung titignan sa range 512MHz to 704MHz.... lalabas na 192MHz lang talga ung BW... . uhm... actually i dont know saan gagamitin... pero may spectrum analyser ung professor namin... so dun namin itetest... dapat walang attenuation, and ung range na freq ay pumasok...

ung link na pinost nyo tinitignan ko po xa as of know... and mejo di ko xa maintindihan hahahaha

[elektroniks_rookie]

Sa mga rf circuits and filters, bihira yung mga ic  ... puros basic rf tansistor circuit amp man or filter.

[chicobulilit]

saan gagamitin at paano niyo ite-test kung tama?

rfdesign.com/mag/combline.pdf

mahirap maghanap niyang cavity filter dahil di naman siya common item, sa mga RF equipments lang siya makikita. kung may mabibili ka man, pre-cut and tuned siya sa common frequency bands na ginagamit like GSM.

needed pa pala ito ng sofware para magawa

[chicobulilit]

Sa mga rf circuits and filters, bihira yung mga ic  ... puros basic rf tansistor circuit amp man or filter.

so meron po bang op amp na kaya magoperate sa BW ko?... as well as sa range of frequencies... and available dito sa raon?? e=qizmo??

[rdpzycho]

^ meron 'yan, pero mahirap hanapin dito. at 'di siya typically ginagamit para gumawa ng filters. LC or Stripline filters ang preferred method pagdating sa RF.

'yung software para lang 'yung i-verify kung tama 'yung design, try to search for Sonnet Lite, pwede siyang gamitin. Ansoft HFSS ang ginagamit ko, meron akong pinost na link dito sa forum somewhere.

pwede niyo muna subukang gumawa ng LC filter, Cauer/Elliptic para sharp ang stops, otherwise, kailangan niyo ng >7th order filter para sharp ang stops. ang problema lang, wala ring mabibili locally ng high SRF inductors. kung eto ang gagawin niyo, maraming Filter Design software na makikita sa net, Filter Light from NuHertz is one (though Filter Free lang ang ginagamit ko, limited to 3rd order), tapos meron ding built-in sa Qucs.

[chicobulilit]

^ meron 'yan, pero mahirap hanapin dito. at 'di siya typically ginagamit para gumawa ng filters. LC or Stripline filters ang preferred method pagdating sa RF.

'yung software para lang 'yung i-verify kung tama 'yung design, try to search for Sonnet Lite, pwede siyang gamitin. Ansoft HFSS ang ginagamit ko, meron akong pinost na link dito sa forum somewhere.

pwede niyo muna subukang gumawa ng LC filter, Cauer/Elliptic para sharp ang stops, otherwise, kailangan niyo ng >7th order filter para sharp ang stops. ang problema lang, wala ring mabibili locally ng high SRF inductors. kung eto ang gagawin niyo, maraming Filter Design software na makikita sa net, Filter Light from NuHertz is one (though Filter Free lang ang ginagamit ko, limited to 3rd order), tapos meron ding built-in sa Qucs.

ok po.. although hindi ko xa maintindihan totally.... hmmmm... what can we do na lang is.... if you can lead us to some way para magawa xa in less time with materials that can be bought here... friday kasi ung deadline... pero actually di naman kami naghahabol... exempted or not ok lang sa amin... pero still i want to know how to build it... within the time being

[rdpzycho]

'yung Combline na ang pinakamadali. 'yan lang kasi 'yung merong locally available materials. next is 'yung Cavity filter, pero medyo mahirap i-construct, kailangan ng blow torch.

here's one sample:

http://www.scottyspectrumanalyzer.com/cavity.html

[insomartin]

^ shucks rocket Science na ito. RF science pala.

[rdpzycho]

mukhang project talaga ni prof 'to, pinapasa sa estudyante.

[Born2BeWired]

Kung walang specified filter parameters yung project nila other than the cutoff frequencies, then there is an easy way of doing it:

Simple filter configuration (with gain):
512MHZ HPF -> Broadband Amplifier -> 704MHz LPF

The HPF and LPF section can be simple LC filters. There is a lot of single chip DC-1GHZ gain block (e.g. CATV Amplifier) available today capable of delivering from 0dbm to 20dbm output at 50-75ohm impedance.

If your professor specified a comprehensive characteristics (e.g. attenuation slope, group delay, amplitude ripple, phase response, off band attenuation) then things can get a lot more interesting. Pray your prof is not reading this

[zrehtiek/keitherz]

oo nga naman. hpf buffer lpf nalang no

[rdpzycho]

Kung walang specified filter parameters yung project nila other than the cutoff frequencies, then there is an easy way of doing it:

Simple filter configuration (with gain):
512MHZ HPF -> Broadband Amplifier -> 704MHz LPF

The HPF and LPF section can be simple LC filters. There is a lot of single chip DC-1GHZ gain block (e.g. CATV Amplifier) available today capable of delivering from 0dbm to 20dbm output at 50-75ohm impedance.

If your professor specified a comprehensive characteristics (e.g. attenuation slope, group delay, amplitude ripple, phase response, off band attenuation) then things can get a lot more interesting. Pray your prof is not reading this

I guess merong binigay 'yan tita Born. ang tingin ko talaga pang-personal ni prof 'to, ayaw niya kasi ng may attenuation sa band na gusto niya.

ang problema lang sa LC tita Born, sa Friday na pinapapasa sa kanila, hirap maghanap ng L dito. though, pwede sila mag-wind.