Question about filtering noise (1/f)

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http://forum.allaboutcircuits.com – In this Texas app note on current sources, on page 12 it talks about reducing noise by filtering it. But it states: "Without the capacitor, noise from the current source would feed directly through to the output. The capacitor filters the noise at a –3dB frequency of 1/(2 • π • R• C), or about 30Hz in this example. Filtering below this frequency will not reduce noise further, since the 30Hz pole is already below the 1/f corner of the current source, and noise can not be reduced by filtering in the 1/f region." http://www.ti.com/lit/an/sboa046/sboa046.pdf But w (Embedded)