passive rc-bandpass with 0dB attenuation in the passband

Started by nukeymusic August 2, 2010
Is it possible to make a passive rc-bandpass filter which has 0dB
attenuation in the passband with only 4 components?

nukey
On Aug 2, 7:50=A0am, nukeymusic <nukeymu...@gmail.com> wrote:
> Is it possible to make a passive rc-bandpass filter which has 0dB > attenuation in the passband with only 4 components? > > nukey
How close to 0dB? What sort of Q (bw/f0)? What's the load?
On Mon, 2 Aug 2010 10:04:29 -0700 (PDT), cassiope
<fpm@u.washington.edu> wrote:

>passive rc-bandpass filter
Key words: passive rc-bandpass filter... an oxymoron, statement and poster :-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Postings via gmail, yahoo, hotmail, aioe, uar or googlegroups, and trolls/feeders, are now automatically kill-filed using Agent v6.0 To be white-listed, send request via the E-mail icon on my website
On 08/02/2010 10:12 AM, Jim Thompson wrote:
> On Mon, 2 Aug 2010 10:04:29 -0700 (PDT), cassiope > <fpm@u.washington.edu> wrote: > >> passive rc-bandpass filter > > Key words: passive rc-bandpass filter... an oxymoron, statement and > poster :-)
It depends on how loose your definition is of "bandpass filter". || ___ Vin o-----||---o--|___|---o-----o Vout || | | | | .-. --- | | --- | | | '-' | | | | | === === GND GND (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de) There's a passive RC bandpass filter for you. It's not a _resonant_ bandpass filter, by any means, but it has a magnitude response that's zero at f = 0, rises to some maximum, then falls to zero as the frequency approaches infinity. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
On 08/02/2010 07:50 AM, nukeymusic wrote:
> Is it possible to make a passive rc-bandpass filter which has 0dB > attenuation in the passband with only 4 components?
Ask your prof? Review your class notes? There's some passive RC filter with not too many components that actually has a bit of voltage gain. It's usefulness is pretty much limited to winning bets in University bars, but it's out there. I can't even remember if it's bandpass, but if it isn't it may have a bandpass cousin. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
On Aug 2, 7:50=A0am, nukeymusic <nukeymu...@gmail.com> wrote:
> Is it possible to make a passive rc-bandpass filter which has 0dB > attenuation in the passband with only 4 components? > > nukey
Can I buy a vowel? Er, make that an inductor....
On Aug 2, 7:04=A0pm, cassiope <f...@u.washington.edu> wrote:
> On Aug 2, 7:50=A0am, nukeymusic <nukeymu...@gmail.com> wrote: > > > Is it possible to make a passive rc-bandpass filter which has 0dB > > attenuation in the passband with only 4 components? > > > nukey > > How close to 0dB? =A0What sort of Q (bw/f0)? =A0What's the load?
exactly 0dB, unloaded, Q to be determined from the other specifications
This configuration won't give 0dB in the passband

On Aug 2, 7:21=A0pm, Tim Wescott <t...@seemywebsite.com> wrote:
> On 08/02/2010 10:12 AM, Jim Thompson wrote: > > > On Mon, 2 Aug 2010 10:04:29 -0700 (PDT), cassiope > > <f...@u.washington.edu> =A0wrote: > > >> passive rc-bandpass filter > > > Key words: passive rc-bandpass filter... an oxymoron, statement and > > poster :-) > > It depends on how loose your definition is of "bandpass filter". > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 || =A0 =A0 =A0 ___ > =A0 =A0Vin =A0o-----||---o--|___|---o-----o =A0 Vout > =A0 =A0 =A0 =A0 =A0 =A0 =A0 || =A0 | =A0 =A0 =A0 =A0 =A0| > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0| =A0 =A0 =A0 =A0 =A0| > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 .-. =A0 =A0 =A0 =A0--- > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | | =A0 =A0 =A0 =A0--- > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | | =A0 =A0 =A0 =A0 | > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 '-' =A0 =A0 =A0 =A0 | > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0| =A0 =A0 =A0 =A0 =A0| > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0| =A0 =A0 =A0 =A0 =A0| > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D=3D=3D =A0 =A0 =A0 =A0=3D=3D=3D > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 GND =A0 =A0 =A0 =A0GND > (created by AACircuit v1.28.6 beta 04/19/05www.tech-chat.de) > > There's a passive RC bandpass filter for you. =A0It's not a _resonant_ > bandpass filter, by any means, but it has a magnitude response that's > zero at f =3D 0, rises to some maximum, then falls to zero as the > frequency approaches infinity. > > -- > > Tim Wescott > Wescott Design Serviceshttp://www.wescottdesign.com > > Do you need to implement control loops in software? > "Applied Control Theory for Embedded Systems" was written for you. > See details athttp://www.wescottdesign.com/actfes/actfes.html
On Aug 2, 9:54=A0pm, "m...@sushi.com" <m...@sushi.com> wrote:
> On Aug 2, 7:50=A0am, nukeymusic <nukeymu...@gmail.com> wrote: > > > Is it possible to make a passive rc-bandpass filter which has 0dB > > attenuation in the passband with only 4 components? > > > nukey > > Can I buy a vowel? Er, make that an inductor....
no inductors allowed here
On 08/02/2010 01:06 PM, nukeymusic wrote:
> On Aug 2, 7:04 pm, cassiope<f...@u.washington.edu> wrote: >> On Aug 2, 7:50 am, nukeymusic<nukeymu...@gmail.com> wrote: >> >>> Is it possible to make a passive rc-bandpass filter which has 0dB >>> attenuation in the passband with only 4 components? >> >>> nukey >> >> How close to 0dB? What sort of Q (bw/f0)? What's the load? > > exactly 0dB, unloaded, Q to be determined from the other specifications
Q is almost meaningless in this case -- any passive RC bandpass filter is going to have a damping ratio greater than 1, and the various definitions of Q only converge for damping ratios much less than one. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html