Electronic apparatus for the observation of signals of biological origin

Claim 1

ELECTRONIC APPARATUS FOR USE IN INVESTIGATING BIOLOGICAL ACTIVITY SUCH AS THE FETAL HEARTBEAT SUPERIMPOSED UPON EXTRANEOUS BACKGROUND BIOLOGICAL ACTIVITY INCLUDING THE MATERNAL HEARTBEAT WHEREIN THE BIOLOGICAL ACTIVITY IS REPRESENTED SUBSTANTIALLY BY SIGNALS IN THE FORM OF AT LEAST TWO INTERMINGLED SERIES OF PULSES OF DIFFERENT PERIODICITY AND WITH EACH SERIES OF PULSES OF DIFFERENT DISTINCTIVE PULSE WIDTH, COMPRISING IN COMBINATION, TRANSDUCER MEANS FOR GENERATING ELECTRICAL SIGNALS CORRESPONDING TO SAID TWO INTERMINGLED SERIES OF PULSES, MEANS FOR SHAPING THE PULSES INTO A SEQUENCE OF SQUARE WAVES OF A DURATION CORRESPONDING TO THE DURATION OF PULSES IN SAID SIGNALS, PULSE DURATION DISCRIMINATING MEANS COUPLED TO SAID SHAPING MEANS TO SELECT ONLY THOSE PULSES OF A PREDETERMINED DURATION FROM SAID SEQUENCES OF PULSES TO FORM A MODIFIED SERIES OF PULSES, INHIBITING MEANS COUPLED FOR RECEIVING THE MODIFIED SERIES OCCURRING WITHIN A PREDETERMINED TIME INTERVAL FOLLOWING A PREVIOUS SIGNAL TO THEREBY PRODUCE AN OUTPUT SEQUENCE OF SIGNALS REPRESENTATIVE OF ONE OF SAID TWO INTERMINGLED SERIES OF PULSES TO THE EXCLUSION OF THE EXTRANEOUS BACKGROUND ACTIVITY.