Telemetry gain adjustment algorithm and signal strength indication in a noisy environment

In a software-controlled, external programmer for programming by downlink telemetry and receiving by uplink telemetry, data to and from an implanted medical device, the improvement for automatically optimizing gain level to minimize interference in the presence of noise in the uplink telemetry receive mode, comprising:

• an adjustable gain amplifier in said programmer dependent upon a gain control input signal gain value for amplifying uplink telemetry radio frequency signals;
• means for detecting uplink telemetry signals amplified by said amplifier which match detect criteria;
• means for setting the gain control input signal applied to said amplifier to a minimum gain value;
• means for starting a first time interval upon setting the gain value;
• means for incrementing said gain value by a predetermined gain factor if no telemetry signal is detected within said first time interval;
• means for comparing said incremented gain value to a maximum gain value and resetting said gain value to said minimum gain value each time said incremented gain value reaches said maximum gain value;
• means for restarting said first time interval when an amplified signal is detected;
• means for measuring the time interval between successive detected uplink telemetry signals- and comparing said time interval to first and second formatted data intervals;
• means for incrementing said gain value by said predetermined factor when the measured interval between successive telemetry signals exceeds both formatted data intervals;
• and
• means for decrementing said gain value by a decrement gain value factor whenever said interval between successive telemetry signals is less than but not equal to said first and second formatted intervals, whereby said gain value linearly increases and decreases as a function of the interval between telemetry signals.

In a software-controlled, external programmer for transcutaneously programming by downlink telemetry and receiving by uplink telemetry data to and from an implanted medical device, the improved apparatus for automatically minimizing interference in the presence of noise comprising:

• adjustable gain amplifier means dependent upon a gain control input signal gain value for amplifying uplink telemetry data signals and providing an output signal;
• threshold detector means for comparing said output signal to preselected detect criteria and providing a telemetry detect signal each time said output signal meets said detect criteria;
• means for measuring the time intervals between successive detect signals and providing detect intervals;
• gain control signal establishing means for providing said gain control input signal gain value in a range between a minimum and maximum value as a function of the detect intervals further comprising:
• means for initially setting said gain value to a predetermined low gain initial value within said range;
• means for increasing said gain value in the absence of detect signals within a first predetermined time interval;
• means for comparing said incremented gain value to a maximum gain value and resetting said gain value to said minimum gain value each time said incremented gain value reaches said maximum gain value.

In a software controlled, external programmer for transcutaneously programming by downlink telemetry and receiving by uplink telemetry data to and from an implanted medical device, the improvement for automatically minimizing interference in the presence of noise and providing a real time indication of the uplink telemetry signal strength to the user of the programmer comprising:

• adjustable gain amplifier means dependent upon a gain control input signal gain value for amplifying uplink telemetry
• thereshold detector means for comparing said output signal data signals and providing an output signal;
• to preselected detect criteria and providing a telemetry detect signal each time said output signal meets said detect criteria;
• means for measuring the time intervals between successive detect signals and providing detect intervals;
• gain control signal establishing means for providing said gain control input signal gain value in a range between a minimum and maximum value as a function of the detect intervals;
• means for complementing and scaling said gain value to provide a signal strength indication numeric value between a minimum and maximum value;
• and
• means for displaying said signal strength value to the user of the programmer in order to simplify positioning of said programmer in relation to said medical device to optimize data transmission.

In a software controlled, external programmer for transcutaneously programming by downlink telemetry and receiving by uplink telemetry data to and from an implanted medical device, the improved method for automatically minimizing interference in the presence of noise comprising the steps of:

• amplifying uplink telemetry data signals as a function of a gain control input signal gain value and providing an output signal;
• comparing said output signal to preselected detect criteria and providing a telemetry detect signal each time said output signal meets said detect criteria;
• measuring the time intervals between successive detect signals and providing detect intervals;
• providing said gain control input signal gain value in a range between a minimum and maximum value as a function of the detect intervals further comprising:
• initially setting said gain value to a predetermined low gain initial value within said range;
• increasing said gain value in the absence of detect signals within a first predetermined time interval;
• and
• decreasing said gain value to said initial value when the increased gain value equals or exceeds the maximum gain value.

In a software-controlled, external programmer for transcutaneously programming by downlink telemetry and receiving by uplink telemetry data to and from an implanted medical device, the improved method for automatically minimizing interference in the presence of noise and providing a real-time indication of the uplink telemetry signal strength to the user of the programmer steps of:

• amplifying uplink telemetry data signals as a function of a gain control input signal gain value and providing an output signal;
• comparing said output signal to preselected detect criteria and providing a telemetry detect signal each time said output signal meets said detect criteria;
• measuring the time intervals between successive detect signals and providing detect intervals;
• providing said gain control input signal gain value in a range between a minimum and maximum value as a function of the detect intervals;
• complementing and scaling said gain value to provide a signal strength indication numeric value between a minimum and maximum value;
• and
• displaying said signal strength value to the user of the programmer in order to simplify positioning of said programmer in relation to said medical device to optimize data transmission.