Abstract: A method and apparatus for efficiently coupling a transceiver to an AC power line transmission system. The preferred embodiment of the coupling system comprises a line coupling network and first and second filter ports. The first filter port is connected to a resonant circuit having bandpass filtering characteristics adapted to the specific needs of the transmitter portion of the transceiver. The second filter port is isolated from the low impedance of the AC power line and is connected to a high quality factor filter having bandpath filtering characteristics adapted to the specific needs of the receiver portion of the transceiver.

Abstract: A cardiovascular monitor having improved safety features and data transmission ability. Sensing devices placed on a patient's body, such as electrocardiogram electrodes and phonocardiogram microphones, are electrically isolated from the data recorder and AC powerline, thereby protecting the patient from dangerously high voltages existing in the recorder and the external power source. Isolation amplifiers are employed in the signal conditioning circuitry at the front end of the recorder. Special isolation transformers are also used to prevent ground loop currents between the signal conditioner and the recorder thus minimizing noise due to powerline leakage. Similarly, isolation amplifiers are used during the playback mode between the recorder and a data processor to avoid ground loop currents between the recorder and the processor.

Abstract: A method and apparatus for efficiently coupling a transceiver to an AC power line transmission system. The preferred embodiment of the coupling system comprises a line coupling network and first and second filter ports. The first filter port is connected to a resonant circuit having bandpass filtering characteristics adapted to the specific needs of the transmitter portion of the transceiver. The second filter port is isolated from the low impedance of the AC power line and is connected to a high quality factor filter having bandpass filtering characteristics adapted to the specific needs of the receiver portion of the transceiver.