"Paul Burridge" wrote in message
...
Hi all,

I need a simple design for a BPF with a centre frequency of 17.2Mhz.,
corner frequencies one Meg or therabouts either side of that and a
reasonably good shape factor (nothing critical here). I don't mind
having to do a bit of tweaking of values myself if anyone has
something close to that they can post. Passive L/C combinations only,
please. (assume the usual 50R nominal Zs.)
Thanks,

p.
--

The BBC: Licensed at public expense to spread lies.

Download the freeware filter design software from

http://www.nuhertz.com/

Their UI is, uh, colorful, but it seems to work. Pay attention to the source
and load impedance. Also, it doesn't like 'engineering' notation (eg:
17.2Meg), so use scientific notation like 17.2e6 instead.

The freeware only designs filters to 3rd order, so if you need better than
that, either dig it out of a book or buy the software. However, it does both
passive and active filters. Its a bargain at twice the price...

Regards,
Bob Monsen

Download RFSim99 and let it do it for you. Download Filter Design
from AADE's site and let it do it for you. Download NuHertz's demo
version of their filter design software and let it do it for you.
There may even be web aplets that will do it for you. And then you
can play with configurations and shape factors and the inevitable
tradeoffs between complexity and shape factor.

Cheers,
Tom

Paul Burridge wrote in message . ..
Hi all,

I need a simple design for a BPF with a centre frequency of 17.2Mhz.,
corner frequencies one Meg or therabouts either side of that and a
reasonably good shape factor (nothing critical here). I don't mind
having to do a bit of tweaking of values myself if anyone has
something close to that they can post. Passive L/C combinations only,
please. (assume the usual 50R nominal Zs.)
Thanks,

p.

In article , (Tom
Bruhns) writes:

Download RFSim99 and let it do it for you. Download Filter Design
from AADE's site and let it do it for you. Download NuHertz's demo
version of their filter design software and let it do it for you.
There may even be web aplets that will do it for you. And then you
can play with configurations and shape factors and the inevitable
tradeoffs between complexity and shape factor.

Or, you can ask me for a free package of LCie4 that I first wrote
back in '93 and have revised only slightly since then. DOS level,
no fancy screens or prettyness in graphics...but LCie4 allows
individual component value variations, actual unloaded Q values,
and Sensitivity (output response or input impedance) to any
specified tolerance of all-Cs or all-Ls. Works under Win98 and
WinXP.

Does 3 to 9 section Lowpass, Highpass, Bandpass, and Bandstop
and 2 to 9 section "resonator" Bandpass filters with choice of "high"
or "low" impedance coupling by C or L. Butterworth, Tchebyshev
(or Chebyshev, heh heh), or one kind of Elliptic, choice of minimum
L or minimum C configurations on odd sections (or 'orders' as some
insist on calling them).

Output Response and Input Impedance are separate analyses, not
part of the calculation of filter component Synthesis. Q of all Cs or
all Ls is frequency-independent; i.e., same specified value at all
frequencies of analysis. That's a compromise to simplify analysis;
purists want a SPICE-like thing, no doubt, where they can model
everything...:-) Chances are those purists never built a real one to
experience the joy of transmutation of paper into hardware.

A "parts listing" command yields a half-S version of a "schematic"
good enough to show the values of separate components, on-screen
or on paper. LCie4 is fast and thorough, lets one play with values
and affect on response until one gets tired of doing so. :-)

Less than 250K in total package size, sent as an e-mail attachment
in response to polite e-mail inquiry. It's free...do not ask for money
back if dissatisfied...

Len Anderson
retired (from regular hours) electronic engineer person

In article , (Tom
Bruhns) writes:

Download RFSim99 and let it do it for you. Download Filter Design
from AADE's site and let it do it for you. Download NuHertz's demo
version of their filter design software and let it do it for you.
There may even be web aplets that will do it for you. And then you
can play with configurations and shape factors and the inevitable
tradeoffs between complexity and shape factor.

Or, you can ask me for a free package of LCie4 that I first wrote
back in '93 and have revised only slightly since then. DOS level,
no fancy screens or prettyness in graphics...but LCie4 allows
individual component value variations, actual unloaded Q values,
and Sensitivity (output response or input impedance) to any
specified tolerance of all-Cs or all-Ls. Works under Win98 and
WinXP.

Does 3 to 9 section Lowpass, Highpass, Bandpass, and Bandstop
and 2 to 9 section "resonator" Bandpass filters with choice of "high"
or "low" impedance coupling by C or L. Butterworth, Tchebyshev
(or Chebyshev, heh heh), or one kind of Elliptic, choice of minimum
L or minimum C configurations on odd sections (or 'orders' as some
insist on calling them).

Output Response and Input Impedance are separate analyses, not
part of the calculation of filter component Synthesis. Q of all Cs or
all Ls is frequency-independent; i.e., same specified value at all
frequencies of analysis. That's a compromise to simplify analysis;
purists want a SPICE-like thing, no doubt, where they can model
everything...:-) Chances are those purists never built a real one to
experience the joy of transmutation of paper into hardware.

A "parts listing" command yields a half-S version of a "schematic"
good enough to show the values of separate components, on-screen
or on paper. LCie4 is fast and thorough, lets one play with values
and affect on response until one gets tired of doing so. :-)

Less than 250K in total package size, sent as an e-mail attachment
in response to polite e-mail inquiry. It's free...do not ask for money
back if dissatisfied...

Len Anderson
retired (from regular hours) electronic engineer person

Paul:

[snip]
I need a simple design for a BPF with a centre frequency of 17.2Mhz.,
corner frequencies one Meg or therabouts either side of that and a
reasonably good shape factor (nothing critical here). I don't mind
having to do a bit of tweaking of values myself if anyone has
something close to that they can post. Passive L/C combinations only,
please. (assume the usual 50R nominal Zs.)
[snip]

Such a design can be achieved with a vert simple formula and a pocket
calculator or slide rule. Why don't you just use Bennett's simple formula
for the maximally flat approximation all pole element values, or Takashi's
simple formulae for the equiripple approximation all pole element values?

Oh... perhaps you want elliptic [Cauer or Darlington] designs or perhaps a
completely general parameter design in that case ypu will need a computer
and will need to do some programming or buy some programming, or
better yet...

Hire a consultant... :-)

Hey, I've designed literally thousands of LC filters over decades in most
frequency ranges, for clients who have paid me well. I have access to very
sophisticated and comprehensive general parameter LC filter design
programs that I have written [In Fortran BTW] over lo these many years
and they are immediately at my disposal.

But... unfortunately for some... I never design filters for free!

I'll do it for you at my usual consulting rates.

My rates are reasonable. Just call or email me to discuss the terms and
conditions.

:-)

--
Peter
Professional Consultant - Signal Processing and Analog Electronics
Indialantic By-the-Sea, FL
peter dot brackett at "eye" triple "e" dot org.
USA area code three two one, number seven two three, nine two five five.


"Paul Burridge" wrote in message
...
Hi all,

I need a simple design for a BPF with a centre frequency of 17.2Mhz.,
corner frequencies one Meg or therabouts either side of that and a
reasonably good shape factor (nothing critical here). I don't mind
having to do a bit of tweaking of values myself if anyone has
something close to that they can post. Passive L/C combinations only,
please. (assume the usual 50R nominal Zs.)
Thanks,

p.
--

The BBC: Licensed at public expense to spread lies.

AADE http://www.aade.com/filter.htm




"Paul Burridge" wrote in message
...
Hi all,

I need a simple design for a BPF with a centre frequency of 17.2Mhz.,
corner frequencies one Meg or therabouts either side of that and a
reasonably good shape factor (nothing critical here). I don't mind
having to do a bit of tweaking of values myself if anyone has
something close to that they can post. Passive L/C combinations only,
please. (assume the usual 50R nominal Zs.)
Thanks,

p.
--

The BBC: Licensed at public expense to spread lies.

For a very simple bandpass design program download program BANDPAS1 from
website below. Also obtain response versus frequency. Download in a few
seconds and run immediately.
--
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

On Thu, 04 Mar 2004 23:43:21 +0000, Paul Burridge
wrote:

Hi all,

I need a simple design for a BPF with a centre frequency of 17.2Mhz.,
corner frequencies one Meg or therabouts either side of that and a
reasonably good shape factor (nothing critical here). I don't mind
having to do a bit of tweaking of values myself if anyone has
something close to that they can post. Passive L/C combinations only,
please. (assume the usual 50R nominal Zs.)
Thanks,

p.

The usual technique is to get a book that has tables of normalized LC
lowpass filters of various types, pick a response you like, and scale
it and map to a bandpass. Williams' "Electronic Filter Design
Handbook" has all this stuff.

It's mildly tedious, so I won't offer to do one for you.

John

Paul Burridge wrote:

Hi all,

I need a simple design for a BPF with a centre frequency of 17.2Mhz.,
corner frequencies one Meg or therabouts either side of that and a
reasonably good shape factor (nothing critical here). I don't mind
having to do a bit of tweaking of values myself if anyone has
something close to that they can post. Passive L/C combinations only,
please. (assume the usual 50R nominal Zs.)

If you have Office 2002 (XP), you can use this web site.

http://www.rfcafe.com/references/_sp...er_plot_ss.htm

--
A man, a plan, a cat, a canal - Panama!

Ho, ho, ho, hee, hee, hee
and a couple of ha, ha, has;
That's how we pass the day away,
in the merry old land of Oz.

On Thu, 04 Mar 2004 23:43:21 +0000, Paul Burridge
wrote:

Hi all,

I need a simple design for a BPF with a centre frequency of 17.2Mhz.,
corner frequencies one Meg or therabouts either side of that and a
reasonably good shape factor (nothing critical here). I don't mind
having to do a bit of tweaking of values myself if anyone has
something close to that they can post. Passive L/C combinations only,
please. (assume the usual 50R nominal Zs.)
Thanks,

p.

Try this 5 pole Chebychev with 0.1dB ripple

Fc=17.2MHz BW=1MHz

CAP 1 2 C=27PF
PLC 2 0 L=1uH C=56PF
CAP 2 3 C=4PF
PLC 3 0 L=.1uH C=80PF
CAP 3 4 C=3PF
PLC 4 0 L=1uH C=80PF
CAP 4 5 C=3PF
PLC 5 0 L=1uH C=80PF
CAP 5 6 C=4PF
PLC 6 0 L=1uH C=56PF
CAP 6 7 C=27PF


tia,




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