Digital receiver response control for the reception of telemetry signals from implanted medical devices

Claim 2

A telemetry receiver for receiving telemetry from an implanted device of the type which transmits information in the form of a series of timed r.f. signals, said receiver including amplifier means for applying gain to said r.f. signals, a threshold level detector which detects the presence of said r.f. signals as amplified by said amplifier means when said amplified r.f. signals exceed a threshold level, and means for verifying the accuracy of said series of signals and for determining whether said signals have been improperly received due to electrical noise, characterised by control means arranged to adjust the response of said receiver in response to a determination that said series of signals have been improperly received and until said determining means indicates that said signals have been properly received, whereby said r.f. signals are caused to exceed said threshold and said electrical noise to fall below said threshold.

Claim 3

A telemetry receiver as claimed in claim 1 wherein said control means is arranged to adjust said threshold level.

Claim 4

A telemetry receiver as claimed in claim 1 wherein said control means is arranged to adjust the gain of said amplifier means.

Claim 5

A telemetry receiver as claimed in claim 3 wherein said control means is arranged successively to reduce said gain.

Claim 6

A programmer for an implanted medical device having means for verifying the programming of an implanted medical device wherein the programmed implanted device transmits telemetry confirmation signals to the programmer after the programming of said implanted device, wherein said signals are encoded binary signals that comprise a plurality of bits; said programmer having variable-gain receiving means and gain control means comprising: means for establishing the gain of said receiving means so that said gain may be altered to eliminate noise when the signal level exceeds the noise level; means for verifying that the encoded signals sent from said implanted device represent valid 1 and 0 data bits; means for processing further information from said implanted device only if all of the bits of said encoded signals are verified as valid 1 and 0 data bits; means for establishing a sampling period and for determining the number of error bits in said signals which are caused by noise and which do not correspond to correct data bits of said encoded signals during said sanpling period; and means for varying said gain by a predetermined amount when the number of said error bits exceeds a predetermined amount during one of said sanpling periods.

Claim 7

A programmer for an implanted medical device having means for verifying the programming of an implanted medical device wherein the programmed implanted device transmits telemetry confirmation signals to the programmer after the programming of said implanted device, wherein said signals are encoded binary signals that comprise a plurality of bits; said programmer having variable-gain receiving means and gain control means comprising: means for establishing the gain of said receiving means so that said gain may be altered to eliminate noise when the signal level exceeds the noise level; means for verifying that the encoded signals sent from said implanted device represent valid 1 and 0 data bits; means for processing further information from said implanted device only if all of the bits of said encoded signals are verified as valid 1 and 0 data bits; means for establishing a sampling period and for determining the number of error bits in said signals which are caused by noise and which do not correspond to correct data bits of said encoded signals during said sanpling period; and means for varying said gain by a predetermined amount when the number of said error bits exceeds a predetermined amount during one of said sanpling periods.

Claim 8

A programmer as claimed in claim 5 wherein the gain of said receiving means is decremented so that said noise level is eventually reduced below said threshold level.