How Do I Draw a Square Instead of a Circle on an XY Oscilloscope?

To draw a square in BeamTracer OSC-1, open CREATOR → GENERATORS → OSCILLATOR, enable both channels, and select SQUARE. Set X (Left) to 0° and Y (Right) to 90°. Select SINE with those same phase settings to draw a circle. Turn on SCOPE to compare the underlying channel waveforms.

Press Play for sound: OSC-1's native recording begins with a 200 Hz sine circle, then switches to the square source. Both channels keep the same frequency and a 90° phase difference. The silent interface demonstrations below start automatically.

Hi, I'm Trina with BeamTracer.com. The four bright corners are a useful clue: a square wave spends much of its time at one of two levels, so the XY point spends much of its time at the four combinations of those levels.

Watch me switch the Oscillator from a circle to a square, sweep the phase, record it and send it to the laser simulator:

How do I compare sine and square waves in OSC-1?

Use the Oscillator's SINE and SQUARE buttons with a fixed frequency and phase difference. Keeping those settings the same lets you see what changing the waveform does. The large display plots left against right; the SCOPE panels underneath show each channel against time.

SINE, SQUARE, then SINE again. The frequency remains 200 Hz. The green XY picture changes together with the cyan LEFT and coral RIGHT waveforms.

Use HIDE KEYS if the keyboard takes space from the comparison. The native recording captures the XY artwork and sound; the surrounding settings and SCOPE panels are shown here in the separate interface walkthrough.

Why are the square's corners brighter than its edges?

A square wave holds near its high or low value for much of each cycle. With two phase-shifted channels, the XY position therefore lingers near four corners. The transitions between those levels draw the connecting strokes. Their short duration makes those strokes much fainter than the corners in this display.

A sine wave changes smoothly through the intermediate values. With equal channel amplitudes and a quarter-cycle offset, that pair traces a circle. Changing only the waveform changes the path and how long the point spends in each part of it.

What happens if I change the phase of a square wave?

Change Y (Right) under PHASE OFFSET while keeping X at 0°. At 0° the two channels move together and the XY picture collapses toward a rising diagonal with bright endpoints. At 45° and 90°, the channels visit different combinations of high and low levels, so the four-corner picture returns with different timing.

SQUARE stays selected while Y changes from 90° to 0°, 45°, then 90°. Read the phase slider and compare the channel transitions with the large XY picture.

The Oscillator's CIRCLE, LINE and ELLIPSE buttons are phase shortcuts. Their names describe the sine-wave result; they do not change a square wave into a sine wave. Read SINE or SQUARE before interpreting the picture. The stereo phase lesson covers those shortcuts using a sine source.

How do I record the picture and its sound together?

Open EXPORT → VIDEO, choose a frame size and resolution, then press RECORD LIVE INPUT. Change the source while recording, open EXPORT again, and press STOP RECORDING. OSC-1 downloads a WebM containing the live XY picture and the source audio, as in the first example.

The recording keeps the experiment together when you share it. Check the downloaded file before posting, and use the transparent recording guide if you need to place the trace over another video.