Design of programmable FIR digital filter to optimize the detection of signals embedded in white noise

The order of a multiband FIR filter is reduced using a programmable passband filter for normalized frequencies. The parameters of a single-band passband filter are extracted from the parameters of a normalized lowpass digital FIR filter using a bilinear transformation. The stopbands of the low-pass digital filter are designed to limit the maximum response from a strong sinusoid, and also to minimize the total energy from the wideband background noise. The parameters of the filter are programmed to detect each frequency band sequentially. The digital filter design is used to shunt the white noise generated by the thermal noise of a 150-W, 100-900-MHz Class A amplifier. The amplifier is fed from five different sensors. In this simulation, the thermal noise amplitude pulses in the frequency range of the amplifier is reduced by about 40 dB