# Talk:Band-stop filter

## Untitled

A bandstop filter is the general case. A notch filter is a specific type of bandstop filter with a very narrow range. - Omegatron 21:36, July 23, 2005 (UTC)

it can be also implimented by using a low and a high pass filter such that low pass filter's cutoff frequency is slightly less than notch frequency and high pass filter's pass band begins at frequency slightly more than notch210.212.8.60 17:06, 5 December 2006 (UTC)suhas

## Schematic

Can we get a scematic here? —The preceding unsigned comment was added by 131.247.9.221 (talk) 16:25, 22 February 2007 (UTC).

I'd like to include these, perhaps someone with better wiki experience can make them look nice.

A simple 1591Hz notch filter.
Magnitude and Phase frequency response of notch filter above.

--JonathonReinhart (talk) 20:50, 19 November 2007 (UTC)

I like these diagrams, but there are a number of issues with the whole page:
• these diagrams should be made consistent with the ones on low-pass filter, high-pass filter and band-pass filter pages.
• What's the assumed load on output?
• What's the Q value for this filter?
• The inductor's value is 1 H; is that a realistic, common value?
• The resistor's value is 10 kΩ; what would a low-impedance version of this circuit look like?
• Is there an RC-only notch filter?
• Some theory about the relation between the component values is warranted.
• How do I make a notch filter that has both a lower and upper cutoff?
• needs more links to reliable pages to satisfy the WP:OR police. Some links to filters here [1] [2] [3].
-- Waveguy (talk) 07:56, 18 February 2010 (UTC)

## examples

I would like to see this filter as both a first order Laplace- and Z-transform (H(s) = ... and H[z] = ...), as well as the resulting schematics and perhaps some frequency responses for the implementation. If someone happens to sit on such pictures/formulas, please write them down here. H(s) = (1-sqrt(a*b)s)^2 / (1 - as)(1 - bs), if I'm not mistaking. --130.236.60.26 (talk) 22:01, 19 October 2009 (UTC)

## Depth

Is there some typical number for how deep a ntoch filter can be? —Preceding unsigned comment added by 130.226.56.2 (talk) 07:37, 19 May 2010 (UTC)

No! Oli Filth(talk|contribs) 00:40, 20 May 2010 (UTC)