To determine system frequency
At a given chopping frequency (F), detector responsivity (Rf
) is related to its responsivity at 0 Hz (R0) as follows:
where τ is the detector time constant.
PbS and PbSe detectors exhibit typical 1/f
noise, and accordingly, at a given chopping frequency, detectivity, D*(f
) can be expressed as:
Typical frequency response of PbS/PbSe detectors is shown below: