Signal level control

A method of dynamically controlling the level of a signal, in which the signal whose level is to be controlled is passed to a level output signal to which its level is controlled, the method comprising:

• providing a prediction of the level of the signal to be passed to the level control stage to the level control stage;
• and
• controlling the level control stage to control the level of the signal based on the signal level prediction.

The method of any one of the preceding claims, comprising, providing the prediction of the signal level by determining the level of a portion of the signal and advising the level control stage of that determined signal level before that portion of the signal reaches the level control stage.

The method of any one of the preceding claims, comprising receiving the signal whose level is to be controlled at an input determining the level of the signal, and passing the determined signal level to the level control stage before the relevant signal portion itself is passed to the level control stage.

A method of dynamically controlling the level of a signal, in which the signal whose level is to be controlled is passed to a level control stage in which its level is controlled, the method comprising:

• determining the level of a portion of the signal to be passed to the level control stage and providing the determined level to the level control stage before the signal portion reaches the level control stage;
• and
• controlling the level control stage to control the level of the signal portion based on the determined signal level.

A method of dynamically controlling the level of a signal, in which the signal whose level is to be controlled is passed to a level control stage in which its level is controlled, the method comprising:

• providing an indication of the level of the signal to be passed to the level control stage to the level control stage before the signal reaches the level control stage;
• and
• controlling the level control stage to control the level of the signal based on the signal level indication.

The method of any one of the preceding claims, comprising first passing the signal whose level is to be controlled through a frequency band limiter so as to establish a known expected minimum frequency component for the signal.

The method of any one of the preceding claims, wherein the signal level is controlled so as to ensure that the maximum predicted signal level will reach but not exceed a permitted signal level range.

The method of any one of the preceding claims, wherein the signal level is controlled by the level control stage scaling the signal by an amount inversely proportional to the maximum predicted signal level.

The method of any one of the preceding claims, comprising comparing the current maximum predicted signal level to a predetermined threshold signal level, and if it exceeds the threshold, controlling the signal level to be lower.

The method of any one of the preceding claims, comprising setting the signal level control at intervals, and not changing the signal level control in between those intervals.

The method of any one of the preceding claims, wherein the signal level control is adjusted only at the zero-crossing points of the signal whose level is to be controlled.

A method of dynamically controlling the level of a signal, in which a signal level control function is applied to a signal whose level is to be controlled, the method comprising only changing the signal level control function at the zero-crossing points of the signal whose level is to be controlled.

An apparatus for dynamically controlling the level of a signal, comprising:

• means for predicting what the level of the signal whose level is to be controlled will be;
• and
• means for controlling the level of the signal on the basis of that prediction.

A method of dynamically controlling the level of a signal substantially as hereinbefore described with reference to any one of the accompanying drawings.

An apparatus for dynamically controlling the level of a signal substantially as hereinbefore described with reference to any one of the accompanying drawings.