Methods and apparatus for blind separation of delayed and filtered sources

A method of recovering a plurality of source signals from an equal plurality of mixed signals, each mixed signal including components of the source signals, comprising the steps of:

• multiplying a channel one mixed signal by a channel one series of different weights associated with a series of different delays and doing a summation to produce a channel one product signal;
• multiplying a channel two mixed signal by a channel two series of different weights associated with a series of different delays and doing a summation to produce a channel two product signal.
• generating a channel one filtered feedback signal from a channel two approximation signal including delaying the channel two approximation signal and multiplying the channel two approximation signal by a series of different weights associated with a series of different delays and doing a summation to produce the channel one filtered feedback signal;
• generating a channel two filtered feedback signal from a channel one approximation signal including delaying the channel one approximation signal and multiplying the channel one approximation signal by a series of different weights associated with a series of different delays and doing a summation to produce the channel two filtered feedback signal;
• adding the channel one filtered feedback signal to the channel one product signal to produce the channel one approximation signal;
• adding the channel two filtered feedback signal to the channel two product signal to produce the channel two approximation signal;
• applying a nonlinear function to the channel one and channel two approximation signals to produce the channel one and channel two output signals;
• and
• adjusting the channel one series of different weights associated with a series of different delays, the channel one filtered feedback signal, the channel two series of different weights associated with a series of different delays, and the channel two filtered feedback signal to maximize entropy of the channel one and channel two output signals, thereby recovering a channel one source signal as the channel one output signal and a channel two source signal as the channel two output signal.

A method of recovering a plurality of source signals from an equal plurality of mixed signals, each mixed signal including components of the source signals, comprising the steps of:

• generating a channel one approximation signal as follows ##EQU15## generating a channel two approximation signal as follows ##EQU16## where:
• w.sub.1k1 and w.sub.2k2 are weights associated with delay k in channel one and channel two,
• w.sub.1k2 and w.sub.2k1 are the weights associated with delay k in channel one and channel two,
• u.sub.1 and u.sub.2 are channel one and channel two approximation signals, and
• x.sub.1 and x.sub.2 are channel one and channel two mixed signals;
• applying a nonlinear function to the channel one and channel two approximation signals to produce a channel one and a channel two output signal;
• and
• adjusting W.sub.1k1, W.sub.2k2, W.sub.1k2, and w.sub.2k1 to maximize entropy of the channel one and channel two output signals,
• respectively, thereby recovering a channel one source signal as the channel one output signal and a channel two source signal as the channel two output signal.