Seismic source

Claim 1

A MECHANICAL BALANCED MODULATOR FOR IMPARTING A SEISMIC WAVEFORM INTO THE EARTH WHICH COMPRISES IN COMBINATION: A FIRST PAIR OF COUNTER-ROTATNG WEIGHTS; A SECOND PAIR OF COUNTER-ROTATING WEIGHTS; A RIGID BASE; MEANS TO SUPPORT SAID FIRST PAIR AND SAID SECOND PAIR OF COUNTERROTATING WEIGHTS FROM SAID BASE; A FREQUENCY FUNCTION GENERATOR FOR GENERATING A VARIABLE OUTPUT FREQUENCY FUNCTION; MEANS TO ROTATE SAID TWO PAIRS OF ROTATING WEIGHTS AT A FREQUENCY VARIABLE IN ACCORDANCE WITH THE OUTPUT OF SAID FREQUENCY FUNCTION GENERATOR; A PHASE FUNCTION GENERATOR FOR GENERATING A VARIABLE OUTPUT PHASE FUNCTION; AND MEANS TO VARY THE PHASE OF THE ANGULAR POSITION OF SAID TWO PAIRS OF COUNTER-ROTATING ECCENTRIC WEIGHTS IN ACCORDANCE WITH THE OUTPUT OF SAID PHASE FUNCTION GENERATOR WHILE EACH PAIR IS ROTATING AT A FREQUENCY IN ACCORDANCE WITH THE OUTPUT OF SAID FREQUENCY FUNCTION GENERATOR.