Abstract: A gain control system for verifying the programming of an implanted medical device is provided for an external programming unit which receives transmitted signals from the implanted unit and verifies if these signals represent valid "1" and "0" data bits. If the signals of an encoded message unit are valid signals then processing continues. If some of the signals are invalid due to noise interference, the gain of the receiver of the programming unit is decremented in steps as long as the error rate exceeds a predetermined number of errors per unit time.

Abstract: In an implantable receiver circuit there is provided a tuned filter responsive to externally provided radio frequency energy bursts. The receiver also includes a pair of oppositely poled diodes for respectively providing positive and negative rectified versions of the energy bursts. The cathode of one diode is coupled through a low-pass filter circuit to an output capacitor and the anode of the other diode is coupled through a low-pass filter to the control electrode of a semiconductor switching device, the main electrodes of which are coupled between the output capacitor and the point of reference potential. With this connection the switching device is rendered conductive during the time no energy burst signals are applied to the tuned circuit thereby allowing the output capacitor to discharge during this time. During the time an energy burst is provided, the second rectifier circuit maintains the switching device non-conductive.