ECG Filter IIR vs. FIR

I'm just wondering about the reason for choosing an FIR filter over an IIR
for ECG signals.

If an IIR filter was used for a signal (in this case, an ECG)which
contained many signal frequencies of interest, could distortion of the
signal be a problem due to the non-linear phase?

I only ask because I've seen papers which use IIR filters for ECG noise
removal, and I'm wondering if some special technique is required to
minimise distortion due to the non-linear phase characteristic, or if in
fact the distortion is so minimal that it's negligible.

Regards,
Mike

On 18 Mar, 19:55, "mike2108" <michealho...@hotmail.com> wrote:
> I'm just wondering about the reason for choosing an FIR filter over an IIR
> for ECG signals.
>
> If an IIR filter was used for a signal (in this case, an ECG)which
> contained many signal frequencies of interest, could distortion of the
> signal be a problem due to the non-linear phase?

There will be 'distorsion' of the signal regardless of
whether the phase is linear or not.

> I only ask because I've seen papers which use IIR filters for ECG noise
> removal, and I'm wondering if some special technique is required to
> minimise distortion due to the non-linear phase characteristic, or if in
> fact the distortion is so minimal that it's negligible.

Ask the cardiologists. Many years ago I saw a presentation on
DSP of ECG signals, where the discussion addressed distorsions
of the signal. One participant mentioned that cardiologists
might interpret the data wrong if they showed certain types
of distorsions. If they can see something that was introduced
by the filter, and interpret it as a medical condition, the
distorsion is too bad, regardless of the filter being IIR or
FIR.

Rune

>On 18 Mar, 19:55, "mike2108" <michealho...@hotmail.com> wrote:
>> I'm just wondering about the reason for choosing an FIR filter over an
IIR
>> for ECG signals.
>>
>> If an IIR filter was used for a signal (in this case, an ECG)which
>> contained many signal frequencies of interest, could distortion of the
>> signal be a problem due to the non-linear phase?
>
>There will be 'distorsion' of the signal regardless of
>whether the phase is linear or not.
>
>> I only ask because I've seen papers which use IIR filters for ECG
noise
>> removal, and I'm wondering if some special technique is required to
>> minimise distortion due to the non-linear phase characteristic, or if
in
>> fact the distortion is so minimal that it's negligible.
>
>Ask the cardiologists. Many years ago I saw a presentation on
>DSP of ECG signals, where the discussion addressed distorsions
>of the signal. One participant mentioned that cardiologists
>might interpret the data wrong if they showed certain types
>of distorsions. If they can see something that was introduced
>by the filter, and interpret it as a medical condition, the
>distorsion is too bad, regardless of the filter being IIR or
>FIR.
>
>Rune
>


Many thanks Rune,

I guess it must just be a relative thing.

Mike