Please consider registering

sp_LogInOut Log In sp_Registration Register

Register | Lost password?
Advanced Search

— Forum Scope —

— Match —

— Forum Options —

Minimum search word length is 3 characters - maximum search word length is 84 characters

sp_Feed sp_TopicIcon
Resonance below 0.707 results in errors/instabilities
No permission to create posts
August 19, 2017
6:17 pm
Forum Posts: 5
Member Since:
August 7, 2017
sp_UserOfflineSmall Offline

Hey there,

I noticed that, while designing the resonant LPF, the frequency response always went to "infinity" when the values for Q went below a certain point, maybe around 0.7. Any idea why this is or how to fix this?


August 21, 2017
8:26 am
W Pirkle
Forum Posts: 247
Member Since:
January 29, 2017
sp_UserOfflineSmall Offline

Use the sample project from Chapter 6 (the 2nd order resonant LPF). There is no issue with Q below 0.707 -- I've taken it all the way down to Q = 0.01 with no problems. The intermediate variable d = 1/Q will fail if Q = 0.0, but you can take the value down pretty close to zero. 

Image Enlarger


Are you working on some other resonant LPF? If not, check your updating equations against the book code.

- Will

Forum Timezone: America/New_York

Most Users Ever Online: 36

Currently Online:
4 Guest(s)

Currently Browsing this Page:
1 Guest(s)

Top Posters:

Skyler: 48

Derek: 46

Peter: 41

Frodson: 40

clau_ste: 39

Gwen: 32

JimmyM: 30

TheSmile: 27

EZB: 24

lppier: 23

Member Stats:

Guest Posters: 1

Members: 522

Moderators: 1

Admins: 4

Forum Stats:

Groups: 11

Forums: 31

Topics: 545

Posts: 2134

Newest Members:

Bill, hill william, NAUN_SONAR, sufy, Diane, Richard, drvenkman, venkman, Jfx, drorh

Moderators: W Pirkle: 247

Administrators: Tom: 67, JD Young: 80, Will Pirkle: 0, W Pirkle: 247