Soft dB Zen-Ten User guide - Manual (Page 11)

User manual for the ZEN 3-channel X-LMS controller Soft dB inc.
schematic shows three generators but only one generator is used for all references.
The reference signals are filtered by an adjustable band-pass filter (F_Rx) (see section
4.1). Next, the contribution of the control output signals is subtracted from the reference
signals. The primary control path filters (CxRx) are used to predict the contribution of the
control outputs on the reference signals (see section 3.1.2). After that, very low-level
white noise is added to each reference signal. The amplitude of this white noise can be
adjusted by the user. White noise added to the reference signals helps prevent filter
control saturation problems when the system being controlled is ill-conditioned (see
section 3.1.3). After the addition of the white noise, the reference signals are filtered by
the secondary control path filters (CxEy). The primary control path filters and the
secondary control path filters are preliminary identified (see section 3.3).
Along with the error signals E(x), the filtered reference signals allow X-LMS
optimization of the Wx control filters. The X-LMS computation is:
x x normx n n
E OutC Ex Mu Wx Wx ⋅ ⋅ + =
+1
The control output signals are obtained by filtering the reference signals with the control
filters. A band-pass filter is used on output signals to avoid aliasing if this option is
selected.
ZEN User Manual p. 11