You didn't change the bandwidth.
If the target signal is max 30Hz and you have a 192kHz sampler, you low pass
at 2x your max frequency (60Hz, but lets say 100Hz for convenience) using
a brick wall digital filter (processed at 192kHz). Then you do a
downsampling
of the signal from 192kHz to 100Hz. Then you end up with lower noise
on the 30Hz signal, but you need to play it back with a 100Hz DAC.
On 7/25/2015 2:22 AM, Peter S wrote:
On 25/07/2015, Peter S <peter.schoffhau...@gmail.com> wrote:
On 23/07/2015, robert bristow-johnson <r...@audioimagination.com> wrote:
depends on what we have available for sample rates. essentially we are
only limited by the laws in Information Theory. if i have a 192 kHz
system and i only need to measure a 30 Hz waveform, there is a lot i can
do to mitigate noise.
By saying "there is a lot i can do to mitigate noise", I assume you
probably mean to do some lowpass filtering to filter out supersonic
frequencies of the signal. If you meant that, here is why it will
worsen your reconstruction and your results: [...]
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