This is a four element Laguerre Filter derived from Finite Impulse Response (FIR) filter by changing
the relative amplitudes of the samples.
However, the lag of a FIR filter is
approximately half the filter length. The result is that if we want greater smoothing we
must accept the additional lag in conventional filters. Laguerre is the method says in one of his articles about Laguerre Filter.
"The FIR filter has a lag of only 1.5 bars and only moderately
smoothes the price data. On the other hand, the Laguerre filter is dramatically
smoother and also has significant lag. You can decrease the smoothing and the lag by
decreasing the damping factor. When the damping factor is reduced to zero, the
Laguerre filter is identical to the FIR filter. This is a simple way to control the action of a
moving average and still use only a few data samples in the calculation."
For further information here is the article about the indicator by the developer John .