DIGITAL PROCESSOR FOR SELECTIVELY SYNTHESIZING SINUSOIDAL WAVEFORMS SAY SUITABLE FOR TESTING GEOPHONES OR COMBINATIONS OF GEOPHONES OF A GEOPHYSICAL DATA ACQUISITION SYSTEM

摘要

DIGITAL PROCESSOR FOR SELECTIVELY SYNTHESIZING SINUSOIDAL WAVEFORMS, SAY SUITABLE FOR TESTING GEOPHONES OR COMBINATIONS OF GEOPHONES OF A GEOPHYSICAL DATA ACQUISITION SYSTEM This disclosure relates to a non-recursive digital synthesizer for producing a surprisingly accurate synthesized sinusoid suitable for testing elements of a geophysical data acquisition system in either a laboratory or a field environment. In accordance with the present invention, ¢ (C/2) +1!-discrete -16-bit binary words are stored in a read-only memory (ROM), representing discrete amplitudes of a digitized sinusoid in a frequency range of 1-500 Hz, and then accessed in succession to a digital-to-analog converter (DAC). A separate suppression circuit means at the output of the DAC is adapted to operate in synchronization with movement of the binary words through the DAC: in that way, glitches generated by the various digital elements of the synthesizer are suppressed. Result: accuracy of the generated sinusoid to the elements under test is assured.