Abstract: In a multiple trace oscilloscope wherein separate traces displayed on a cathode ray tube screen are updated in succession, a random access memory is addressed by the count output of a programmable counter which increments its count each time the oscilloscope finishes updating one trace prior to updating a next trace. Data stored in the random access memory at the storage location addressed by the count is utilized to control attributes of the next trace to be updated by controlling the switching positions of attribute control switches which select the horizontal, vertical and intensity control signals controlling the appearance of each trace.