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[Octave-bug-tracker] [bug #38528] Function ellipord outputs complex filt
From: |
anonymous |
Subject: |
[Octave-bug-tracker] [bug #38528] Function ellipord outputs complex filter order for high-pass filter |
Date: |
Sat, 16 Mar 2013 13:58:35 +0000 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.19 (KHTML, like Gecko) Ubuntu/11.04 Chromium/18.0.1025.151 Chrome/18.0.1025.151 Safari/535.19 |
URL:
<http://savannah.gnu.org/bugs/?38528>
Summary: Function ellipord outputs complex filter order for
high-pass filter
Project: GNU Octave
Submitted by: None
Submitted on: Sat 16 Mar 2013 01:58:34 PM UTC
Category: Octave Forge Package
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: Incorrect Result
Status: None
Assigned to: None
Originator Name:
Originator Email: address@hidden
Open/Closed: Open
Discussion Lock: Any
Release: 3.2.4
Operating System: GNU/Linux
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Details:
When using the function ellipord to calculate the order of a high-pass* Cauer
filter, it returns a complex number whereas the order of a filter should
always be a real and positive integer. The following line reproduces the
issue:
>> ellipord(0.955,0.945,1,20)
output: ans = 4 - 2i
Based on order calculations of bandpass filters and a lowpass filter with the
same distance between the passband an the stopband, maximum passband
attenuation and minimum stopband attenuation, an order of 3 or 4 is expected.
A file with all calculated filters is attached.
*High-pass filter: a filter with only one passband edge and one stopband edge
with the passband edge at a higher frequency than the stopband edge. In other
words, all frequencies beneath the stopband edge are suppressed and all
frequencies above the passband edge are preserved.
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Sat 16 Mar 2013 01:58:34 PM UTC Name: reproduce_ellipord_bug.m Size:
1kB By: None
<http://savannah.gnu.org/bugs/download.php?file_id=27612>
_______________________________________________________
Reply to this item at:
<http://savannah.gnu.org/bugs/?38528>
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- [Octave-bug-tracker] [bug #38528] Function ellipord outputs complex filter order for high-pass filter,
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