Patent ID: 7126504

Claim:
A system, comprising: (A) a material metering machine having a load cell, the load cell being configured to generate an analog signal, the analog signal being indicative of a load on the load cell; (B) an analog-to-digital converter configured to convert the analog signal into a digital signal, the digital signal having a sampling rate of 307.2 kHz; (C) a preliminary decimation element comprising: (C1) a first finite-impulse-response (FIR) filter having a decimation ratio of 16, the first FIR filter being configured to reduce the sampling rate of the digital signal from 307.2 kHz to 19.2 kHz; and (C2) a second FIR filter serially coupled to the first FIR filter, the second FIR filter having a decimation ratio of 16, the second FIR filter being configured to reduce tbe sampling rate of the digital signal from 19.2 kHz to 1200 Hz; (D) a primary decimation element serially coupled to the preliminary decimation element, the primary decimation element comprising: (D1) a third FIR filter having a decimation ratio of 2, the third FIR filter being configured to reduce the sampling rate of the digital signal from 1200 Hz to 600 Hz; (D2) a fourth FIR filter having a decimation ratio of 10, the fourth FIR filter being configured to reduce the sampling rate of the digital signal from 600 Hz to 60 Hz; and (D3) a fifth FIR filter having a decimation ratio of 6, the fifth FIR filter being configured to reduce the sampling rate of the digital signal from 60 Hz to 10 Hz; and (E) a filter bank serially coupled to the primary decimation element, the filter bank comprising: (E1) selectable filters, each filter being configured to reduce the noise, the selectable filters including a filter having a sub-hertz 3-dB cutoff frequency, the selectable filters comprising a filter selected from the group consisting of: (E1a) a SINC filter; and (E1b) a raised cosine filter; and (E2) a selectable filter switch configured to select a selectable filter, the selectable filter being selected as a function of operating criteria, the operating criteria being associated with the material metering machine, the operating criteria being determined through a closed feedback loop.