page_title: Oscilloscope
section_title: Dual-trace controls
hierarchical_section_title: Oscilloscope / Features and uses / Front panel controls / Dual-trace controls
caption_attribution_description: English: Dual-trace controls green trace = Y = 30*sin(0.1*t)+0.5 teal trace = Y = 30*sin(0.3*t)
context_page_description: An oscilloscope, previously called an oscillograph, and informally known as a scope or o-scope, CRO, or DSO, is a type of electronic test instrument that graphically displays varying signal voltages, usually as a calibrated two-dimensional plot of one or more signals as a function of time. The displayed waveform can then be analyzed for properties such as amplitude, frequency, rise time, time interval, distortion, and others. Originally, calculation of these values required manually measuring the waveform against the scales built into the screen of the instrument. Modern digital instruments may calculate and display these properties directly.
  The oscilloscope can be adjusted so that repetitive signals can be observed as a persistent waveform on the screen. A storage oscilloscope can capture a single event and display it continuously, so the user can observe events that would otherwise appear too briefly to see directly.
  Oscilloscopes are used in the sciences, medicine, engineering, automotive and the telecommunications industry. General-purpose instruments are used for maintenance of electronic equipment and laboratory work.
context_section_description: Each input channel usually has its own set of sensitivity, coupling, and position controls, though some four-trace oscilloscopes have only minimal controls for their third and fourth channels.
  Dual-trace oscilloscopes have a mode switch to select either channel alone, both channels, or (in some) an X‑Y display, which uses the second channel for X deflection. When both channels are displayed, the type of channel switching can be selected on some oscilloscopes; on others, the type depends upon timebase setting. If manually selectable, channel switching can be free-running (asynchronous), or between consecutive sweeps. Some Philips dual-trace analog oscilloscopes had a fast analog multiplier, and provided a display of the product of the input channels.
  Multiple-trace oscilloscopes have a switch for each channel to enable or disable display of the channel's trace.
caption: Dual-trace controls green trace = y = 30 sin(0.1t) + 0.5 teal trace = y = 30 sin(0.3t)