Highpass Filter Selection for Blocking 60 Hz & Beyond

  • Thread starter Thread starter m718
  • Start date Start date
  • Tags Tags
    Filter
Click For Summary

Discussion Overview

The discussion focuses on the selection of highpass filters for effectively blocking 60 Hz frequencies while allowing some attenuation up to 250 Hz. Participants explore various filter types and configurations, emphasizing constraints and performance characteristics.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants inquire about the specific constraints for the highpass filter, such as order, type (passive or active), gain tolerance, and corner frequency tolerance.
  • One suggestion involves using two Butterworth filters, a highpass and a lowpass, with appropriately chosen cutoff frequencies to block the 60 Hz frequency.
  • A participant describes their experience with notch filters, noting that despite using three different designs, the filters only attenuated frequencies by about 10% rather than effectively blocking 60 Hz.
  • Another participant requests a schematic of the notch filters and suggests that the 60 Hz interference might be entering the circuit through an alternate path.

Areas of Agreement / Disagreement

Participants express differing views on the effectiveness of notch filters versus highpass filters, and the discussion remains unresolved regarding the best approach to block 60 Hz frequencies.

Contextual Notes

Participants have not fully defined the constraints or specifications for the filters, and there are unresolved questions about the performance of the notch filters in the described setup.

m718
Messages
88
Reaction score
0
Which type of highpass filter attenuates best?
I want to block 60 hz but its ok if there's some attenuation up to 250 hz.
I can't use notch filter.
 
Engineering news on Phys.org
m718 said:
Which type of highpass filter attenuates best?
I want to block 60 hz but its ok if there's some attenuation up to 250 hz.
I can't use notch filter.

Depends on what you mean by "best". What are the constraints on your filter? What order filter? Passive or active? Gain tolerance in the passband? Tolerance on the corner frequency?
 
You could use two Butterworth filters, highpass and lowpass (the order depends on you constraints as berkeman said) and choose their cutoff frequencies such that the 60 Hz frequency is blocked.
 
I made three different notch filters to block 60 hz from pickup coil that goes to a single opamp amplifier, I put the filter before the amplifier and it doesn't blockout 60 hz, it just attenuates all frequencies about 10%. why is this happening?
 
m718 said:
I made three different notch filters to block 60 hz from pickup coil that goes to a single opamp amplifier, I put the filter before the amplifier and it doesn't blockout 60 hz, it just attenuates all frequencies about 10%. why is this happening?

Please post a schematic if you can. Also, maybe the 60Hz pickup is getting into the circuit some other way?
 

Similar threads

Recommendation Needed for a Spectrum Analyzer
  • · Replies 46 ·
2
Replies
46
Views
4K
Low noise 60 Hz notch filter circuit
  • · Replies 2 ·
Replies
2
Views
3K
Finding the Right Filter for -140 dB 60 Hz Attenuation
  • · Replies 18 ·
Replies
18
Views
17K
Taps for simple IIR Filter in GNU Radio
  • · Replies 1 ·
Replies
1
Views
3K
Sources of voltage ripple in buck converter
  • · Replies 13 ·
Replies
13
Views
4K
Finding R and C values for an active second-order bandpass filter
  • · Replies 16 ·
Replies
16
Views
4K
Can a throat microphone effectively filter out engine noise from human voice?
  • · Replies 11 ·
Replies
11
Views
4K
Induction Heater at 50Hz or 60Hz from Kitchen Wall Outlet.
  • · Replies 4 ·
Replies
4
Views
3K
UV filter for home central heating?
  • · Replies 17 ·
Replies
17
Views
1K
Help with understanding of RF theory-Kinetic inductance parametric amp
  • · Replies 1 ·
Replies
1
Views
2K