The performance of the filter was exceptional in its testing. The
filter managed to filter out all noise signals which were not in the
passband of the filter. The output of the signal was an exact
reconstruction of the original signal with some minor attuenuation. the
filter attenuates at the specified passbands and falls within the
transition frequencies.
During one of the tests was conducted using a noise generator. When
the filter was tested with this generator, there was still noise present
in the output signal. What was found was a phenomenon called "aliasing".
which is defined as undersampling a signal thus causing the undersampled
signal to lose information. The undersampled noise will be now
represented as a noise signal of a lower frequency. The new noise
component will be the difference between the sampling frequency and the
noise component. If the noise difference falls between the passband of
the filter, then the noise will not be filtered. to alleviate this
problem, an analog lowpass filter was introduced prior to the digital
filter to attenuate the high frequencies. A block diagram of this will
be shown below.
