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From: john1987 on 26 Jul 2010 23:49
Hi,

Thanks for the replies. Honestly this is not a home work. I am not
good at Analog design at all and learning the ropes. How does the
bandpass filter work with Vin positive and Vin neagtive proposed by
Jim.

John
From: Grant on 27 Jul 2010 05:52
On Mon, 26 Jul 2010 20:49:03 -0700 (PDT), john1987 <conphiloso(a)hotmail.com> wrote:

>Hi,
>
>Thanks for the replies. Honestly this is not a home work. I am not
>good at Analog design at all and learning the ropes. How does the
>bandpass filter work with Vin positive and Vin neagtive proposed by
>Jim.

Allpass, not bandpass.
>
>John
From: Jim Thompson on 27 Jul 2010 10:58
On Mon, 26 Jul 2010 20:49:03 -0700 (PDT), john1987
<conphiloso(a)hotmail.com> wrote:

>Hi,
>
>Thanks for the replies. Honestly this is not a home work. I am not
>good at Analog design at all and learning the ropes. How does the
>bandpass filter work with Vin positive and Vin neagtive proposed by
>Jim.
>
>John

-Vin => Vin _inverted_ by using an OpAmp with unity-gain-inverting
feedback.

To understand how the R-C network makes an AllPass you'll need the
capability to do Laplace math (at least in the "Laplace notation" form
developed by Heaviside: http://en.wikipedia.org/wiki/Low-pass_filter )
-or- the ability to do complex math (j-Omega-C, etc.)

...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 |

Spice is like a sports car...
Performance only as good as the person behind the wheel.
From: Joel Koltner on 27 Jul 2010 13:56
"john1987" <conphiloso(a)hotmail.com> wrote in message
news:b9464fde-1d31-4791-ba18-0414ce50f5b2(a)c16g2000vbp.googlegroups.com...
> Thanks for the replies. Honestly this is not a home work. I am not
> good at Analog design at all and learning the ropes. How does the
> bandpass filter work with Vin positive and Vin neagtive proposed by
> Jim.

Do you understand how superposition works? If so, the intuitive way to view
that circuit is that with the "-Vin" side set to ground, the output from "Vin"
is your standard low-pass RC filter (...with 45 degree phase shift at
1/(2piRC), etc.). Then, with "Vin" set to ground, the output from the "-Vin"
side is your standard high-pass CR filter. The overall output is the sum of
these two.

Alternatively, you can just crank through the algebra... are you familiar with
phasors (or Laplace transforms) and Kirchoff/Noton/Ohm's laws?

(I have a book aimed at electronic techs getting 2-year degrees, and their
insistance on avoiding phasors makes a lot of the problem much more difficult;
I felt they were doing their students a disservice, as I think you can teach
people how to *use* phasors in just a couple of classes, which is of great
utility even if they don't fully understand the bit of math behind it or the
connection with Fourier/Laplace transforms.)

---Joel


From: whit3rd on 27 Jul 2010 17:54
On Jul 26, 5:25 pm, Jim Thompson <To-Email-Use-The-Envelope-I...(a)On-My-
Web-Site.com> wrote:


> All-pass:
>
>   Vin      ___       Vout
>     o-----|___|---o---o
>                   |  
>                   |  
>                  ---  
>                  ---
>                   |  
>                   |  
>                   o
>                  -Vin
>
> Get -VIN (180° with an inverting OpAmp)

If there's an inverting amp allowed, an integrator with
a (simple darlington?) modest-gain amplifier would do the job.
I'd dislike paying for a good op amp just to massage sinewaves
at 200 kHz.
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