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Analysis Help
Parameter: Filter gain factor


Full name: Amplification factor (gain) of filter
Range: [ -10000, 10000 ]
Initial value: 1

Affects: Filter operation

Low-pass filtering removes high frequency noise from the signal, including the noise from quantisation error when digitising a weak signal. However, if the signal amplitude is still small, the quantisation error is reintroduced when the signal is stored in the waveform file after filtering.

By setting this parameter, you can change the gain factor of the digital filter to boost the signal strength, minimising the effect of quantisation error reintroduced when storing the filtered signal. It does nothing, however, for any of the original quantisation error still in the signal after filtering. This amplification is particularly useful if you are going to differentiate the resulting signal. A negative gain will invert the signal, but not the scaling of the signal.

The program checks this gain to prevent overflow of the signal. It does this by checking against the "Min window discr." and "Max window discr." parameters, which you must set to the range of levels you want to keep in the signal.

 

Key sequence  Parameter Initial Value
<Esc>MFA  Filter gain factor  1

 


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