Method and system for precise time based presentation of recorded medical data

A system for recording and presenting time based medical data, said system comprising:

• a recorder device for recording time based medical data;
• a presentation device for presenting recorded data at an actual presentation speed which varies in response to variations of a variable speed control signal wherein actual presentation speed varies linearly in response to variations of said variable speed control signal which do not exceed a selected maximum during a given period of time and nonlinearly in response to variations of said variable speed control signal which exceed said selected maximum during a given period of time;
• a speed control detection circuit coupled to said presentation device for periodically determining a difference between a desired presentation speed and said actual presentation speed;
• and
• a speed control signal generation circuit coupled to said speed control detection circuit and said presentation device for generating and varying said variable speed control signal in response to said difference between said desired presentation speed and said actual presentation speed, said speed control signal generation circuit comprising:
• a linear control circuit for periodically varying said variable speed control signal at a first rate in response to a difference between said desired presentation speed and said actual presentation speed which results in a variation of said variable speed control signal which does not exceed said selected maximum and for coupling said variable speed control signal to said presentation device;
• and
• a nonlinear control system for periodically varying said variable speed control signal at a constant rate in response to a difference between said desired presentation speed and said actual presentation speed which results in a variation of said variable speed control signal wherein said variation does exceed said selected maximum during a given period of time and for coupling said variable speed control signal to said presentation device wherein said presentation device continues to operate in a stable manner despite the occurrence of large variations in presentation speed.

A method for precise time based presentation of recorded data utilizing a presentation device which presents recorded data at an actual presentation speed which varies in response to a variations of variable speed control signal wherein said actual presentation speed varies linearly in response to variations of said variable speed control signal which do not exceed a selected maximum during a given period of time and nonlinearly in response to variations of said variable speed control signal which exceed said selected maximum during a given period of time, said method comprising the steps of:

• periodically determining a difference between a desired presentation speed and said actual presentation speed;
• periodically generating and varying said variable speed control signal in response to a difference between said desired presentation speed and said actual presentation speed at not greater than a first rate in response to a difference between said desired presentation speed and said actual presentation speed which results in a variation of said variable speed control signal which does not exceed said selected maximum during a given period of time and at a constant rate in response to a difference between said desired presentation speed and said actual presentation speed which results in a variation of said variable speed control signal which does exceed said selected maximum during a given period of time wherein said presentation device continues to operate in a stable manner despite the occurrence of large variations in presentation speed;
• and
• coupling said variable speed control signal to said presentation device.