Sallen Key Low Pass Filter, bandpass filter

[Maglatron]

so I added some up on mouser, and chose the capacitors as film type they come to £130.50 Is that too much???

 

[Maglatron]

will film type do??? cheers

 

[Maglatron]

I took the plunge and bought them!

 

[bertus]

Hello,

Most times film capacitors will have a better quality as ceramic capacitors.

Bertus

 

[Maglatron]

in this envelpe detector are the cap values in uf

 

[bertus]

Hello,

That is a very complicated detector.
A simple diode with a capacitor to ref might even do the trick.

Bertus

 

[Maglatron]

ok thats fine it said precision envelope detector can you recommend a setup please will that be generic for all the filters perhaps a good youtube video maybe

 

[Maglatron]

I found this for RC selection with known carrier frequency and base frequency what are the differences between the two

 

[bertus]

Hello,

Have a look at the following picture for the effect of the RC on the shape of the envelope:

The fine signal shape is the audio signal. The thick line is the created envelope.

You could try 100 nF with 1 MOhm for RC and see how it behaves.

Bertus

 

[Maglatron]

okie doekey will do!!

 

[Maglatron]

Something just occured to me, can you simulate a 45hz signal that varies in amplitude in spice, I'm sure you can, then how do you do that?

 

[bertus]

Hello,

The following page will tell you a lot about sources in ltspice:

LTspice-Types of Voltage and Current Sources | Spiceman

This article introduces the various types of voltage and current sources available in LTspice. Independent Voltage and C

spiceman.net

Bertus

 

[Maglatron]

I just skimmed through there is nothing with frequecy

 

[bertus]

Hello,

Here is a page with an example of a WAV file in the simulation:

.wave : LTspice -- Write Selected Nodes to a .Wav File | Spiceman

This article details the use of the dot command ".wave". ".wave" can be used to output the "voltage" or "current" of a s

spiceman.net

https://vmascagn.web.cern.ch/LABO_2020/LTspice_and_wav_files.html

Bertus

 

[Maglatron]

Nice one bertus, can you have one wav file of 45hz with varying ampitude for say a minute?
I will read now!

 

[bertus]

Hello,

You could create some wav files in Audacity:

Audacity (audio editor) - Wikipedia

en.wikipedia.org

Audacity ® | Free Audio editor, recorder, music making and more!

Audacity is the world's most popular audio editing and recording app. Edit, mix, and enhance your audio tracks with the power of Audacity. Download now!

www.audacityteam.org

Bertus

 

[Maglatron]

ok cool

 

[Maglatron]

ok got the program I also use reaper how do you setup a frequency of 45Hz with Audacity?

 

[bertus]

Hello,

In the menybar there is generate. You can create several types in there.
With chirp you can create a frequency shift over time.
That way you could test the behaviour of a filter.

Bertus

 

[Maglatron]

Hello,

In the menybar there is generate. You can create several types in there.
With chirp you can create a frequency shift over time.
That way you could test the behaviour of a filter.

Bertus

ok good idea, but first off I want to vary the amplitude of the 45z so that its not a constant volume, this is because I believe that it will be better for designing the envelope detector settings of the cap and resistor