Mechanical filter with attenuation poles on both sides of passband

Claim 1

A MECHANICAL FILTER STRUCTURE COMPRISING: A FIRST PLURALITY OF DISC COMPRISING FIRST, SECOND, THIRD AND FOURTH DISCS ARRANGED IN THE ORDER LISTED IN A STACKED POSITION WITH THEIR AXES LYING ALONG A COMMON LINE AND SPACED APART A DISTANCE LESS THAN HALF THE WAVELENGTH OF THEIR NATURAL RESONANT FREQUENCY; SAID FIRST DISC BEING A DIAMETER MODE TYPE DISC AND SAID SECOND, THIRD, AND FOURTH DISC BEING CIRCULAR MODE TYPE DISCS; FIRST WIRE-LIKE COUPLING MEANS EXTENDING ALONG THE STACK OF DISC AND SECURED TO THE PERIMETERS THEREOF TO HOLD SAID DISCS IN SAID STACKED ARRANGEMENT; SAID FIRST WIRE-LIKE COUPLING MEANS BEING SECURED TO POINTS ON THE PERIMETER OF SAID DIAMETER MODE DISC, ALL HAVING A FIRST PHASE OF VIBRATION; SECOND WIRE-LIKE BRIDGING MEANS SECURED TO SAID FIRST DISC AND SAID FOURTH DISC AND BRIDGING ACROSS SAID SECOND AND THIRD DICSC; SAID SECOND WIRE-LIKE BRIDGING MEANS BEING CONNECTED TO A POINT ON THE PERIMETER OF SAID FIRST DISC HAVING A PHASE OF VIBRATION OPPOSITE TO THAT OF SAID FIRST PHASE OF VIBRATION; THE PARAMETERS OF SAID DISCS, SAID FIRST WIRE-LIKE COUPLING MEANS, AND SAID SECOND WIRE-LIKE BRIDGING MEANS BEING IN ACCORDANCE WITH THE EXPRESSION: