Proof that first difference filter amplifies noise

1. Can filter improve signal quality Why?
2. What is the attenuation of a first order filter?
3. What does a first order filter do?
4. What is the advantage of filtering the data signal before modulation?

Can filter improve signal quality Why?

The main reason to filter a signal is to reduce and smooth out high-frequency noise associated with a measurement such as flow, pressure, level or temperature. A common example is the noise associated with the differential pressure (DP) across an orifice plate used to infer flow rate.

What is the attenuation of a first order filter?

For example, a first-order filter will have an attenuation rate of –20 dB/decade, while a fourth-order filter will have an attenuation rate approaching –80 dB/decade.

What does a first order filter do?

First-order filters, both low-pass and lag, work by reducing gain near and above the resonant frequency. They restore some of the gain margin that was taken by the increased gain of the motor/load mechanism at the resonant frequency and above.

What is the advantage of filtering the data signal before modulation?

Filtering takes advantage of the difference between spectra of noise and target to improve SNR, attenuating the data more in the spectral regions dominated by noise, and less in those dominated by the target.