|
1.
There
are many other 50/60Hz notch filters available, what makes the
HumBug so special?
The
HumBug is NOT a filter, making this the main reason it is a
special, perhaps unique product. Filtering often results in
phase shifts, frequency loss, amplitude errors, DC shifts, time
delays or digital distortion. The HumBug will eliminate
50/60Hz electrical interference (and harmonics) without altering
your signal of interest.
2.
I am impressed by the ability of the HumBug to remove mains noise,
but how does it work?
A
noisy waveform is the summation of two separate components.
One component is the biological signal of interest and the other
is noise of various forms. These forms of noise include random fluctuations generated by the sensor, amplifier and
background biological noise in the vicinity of an experimental setup. The
HumBug is designed to cancel electrical interference. It
constructs a replica of noise embedded within the input signal and
subtracts this replica from the noisy signal as it passes through
the device. The end result is an output which contains only
the signal of interest.
3.
How rapidly is the HumBug able to adapt to changing noise levels?
The
HumBug adapts rapidly when the input signal is dominated by noise
and proceeds more slowly when low amplitude noise is embedded
within continuous physiological activity. Adaptation is also
slower for harmonics with frequencies greater than 1kHz.
4.
I have a multi-channel recording setup and would like to use the
HumBug on each of the channels, can I use the HumBug to do this?
Yes,
but please remember that the HumBug is a single channel device,
therefore you will need one HumBug for each channel of interest.
5.
I have just purchased a HumBug but I am finding that the noise
cancellation is inadequate. Do you have any suggestions on
what the problem might be?
-
First
you should check that the HumBug is configured to remove noise
of the appropriate frequency. You can check this as it
should be indicated next to the power connection socket on the
back of the unit.
-
It
may be possible that the noise you are experiencing is not
picked up from the mains supply.
-
If
the peak to peak noise is too large for the HumBug to
completely cancel. If so, the indicator will continue to
flash red. The HumBug cannot eliminate noise greater
that 1V peak to peak.
-
Likewise,
low amplitude noise (<15mv) can be difficult to remove, so
it is suggested that you increase the gain of your signal to
ensure that the amplitude is greater than 15mV peak to peak.
|
