Dynamic adjustment of noise separation in data handling, particularly voice activation

A method of activation, comprising:

• defining a time period;
• comparing an input signal with a reference level for a portion of the input signal;
• when said comparing satisfies a condition, generating an activation signal and then repeating said comparing;
• and
• when said comparing does not satisfy the condition repeatedly and successively for the time period, changing the reference level to a function of the input signal and then repeating said comparing.

An activation control, comprising:

• an input node to provide an input signal;
• a reference node to provide a reference signal;
• a comparator operatively coupled to said nodes to compare the input signal with the reference signal and to provide a control when a compared relation between the input signal and the reference signal satisfies a condition;
• a first generator coupled to said comparator and controlled by said comparator to generate an activation signal in response to the control;
• and
• a timer control coupled to said comparator and determining elapsed time when the control is continuously and repeatedly absent, and in response to the elapsed time exceeding a reference, outputting a time control;
• and
• a second generator coupled to said timer control, generating the reference signal to said reference node and dynamically changing a level of the reference signal in response to the time control.

A voice activated speech transmitter that is dynamically adaptive to noise mixed with valid speech in an input signal, comprising:

• means for providing a succession of activation signals indicating speech by comparing power of corresponding successive frames of an input signal with a reference noise power threshold;
• means for transmitting the frames successively in response to successive ones of the activation signals;
• and
• means for dynamically changing the reference noise power threshold when no activation signal is provided for a substantial predefined continuous time period representing a plurality of successive frames.