Domain: Engineering — Communications Engineering
Target concept: QAM Quadrature Amplitude Modulator

Video generation prompt: The signal generator outputs a binary digital signal, which is connected to a QAM quadrature amplitude modulator. The oscilloscope's dual channels display the digital signal and the carrier signal, respectively.

Evaluation guide:
(i) Target concept: Real-time dual-channel oscilloscope visualization of independent digital and analog input signals feeding a QAM system.
Minimum mechanism: Signal generator must produce discrete-level binary output; carrier source must produce continuous periodic waveform; oscilloscope must accept and render two inputs without cross-talk or scaling conflict; no modulation processing is required or depicted: only input signal verification.
(ii)Storyline: Frame 1–3: Static wide shot showing signal generator, QAM modulator, and oscilloscope arranged left-to-right; cables visibly link generator→modulator, plus a separate branch cable from the signal generator directly to oscilloscope CH1 (tapped before the modulator, so CH1 shows the raw digital input rather than any modulated output), plus separate carrier→oscilloscope CH2. Frame 4–7: Close-up on oscilloscope screen with two stable, non-overlapping waveforms (top/bottom or left/right), one square, one sinusoidal, both fully in view and continuously rendered. Frame 8–10: Slight camera push-in maintaining full waveform visibility and cable continuity; no device movement, lighting shift, or display interruption occurs at any point.

Manual:
Experimental Procedure
1. Connect signal generator output to QAM modulator input.
2. Tap the signal generator's digital output directly to oscilloscope CH1 (before it reaches the QAM modulator, as a verification point); connect the carrier source directly to oscilloscope CH2.
3. Power on all devices; set signal generator to binary square wave output; set carrier source to sine wave.
Observation of Experimental Phenomena
Oscilloscope displays two simultaneous waveforms: CH1 shows the clean binary square wave (digital signal) feeding the modulator; CH2 shows the smooth, periodic sine wave (carrier signal) feeding the modulator — these are the modulator's two raw inputs, not its modulated output.
Summary of Experimental Principles
QAM modulation requires separate digital baseband and analog carrier inputs; the oscilloscope's dual-channel mode enables direct side-by-side verification of these two essential input signals before they reach the modulator.

Prompt Grounding rubric:
level_1: None of the three devices (signal generator, QAM modulator, oscilloscope) appear anywhere in the video; or the digital signal and the carrier signal never appear together in any form; or no two-channel oscilloscope display is shown at all.
level_2: At least one device appears (for example, only the oscilloscope), but the signal generator and the QAM modulator are missing; or the oscilloscope shows only a single waveform instead of two distinct channels; or a digital trace and a carrier trace are both shown but neither is visibly tied to a specific channel.
level_3: The signal generator, the QAM modulator, and the oscilloscope all appear; the oscilloscope shows two waveforms at once, one recognizable as a square-edged binary trace and the other as a smooth sinusoidal trace; a cable is visible running from the signal generator toward the modulator's input, and cables are visible running from the signal generator (or a branch of it) and from the carrier source toward the oscilloscope's two channel inputs.
level_4: Everything at level 3 holds, and in addition the two oscilloscope channels are clearly told apart: by position (e.g., top vs. bottom), by color (e.g., one trace green, one yellow), or by an on-screen label such as 'CH1: Digital' / 'CH2: Carrier'; and the cabling from the signal generator to the modulator, and from the signal generator and carrier source to the oscilloscope, forms a continuous, unbroken path with no gaps.
level_5: Everything at level 4 holds, and in addition the square wave shows crisp, high-contrast transitions with uniform pulse width and no baseline drift; the sine wave stays smooth and unbroken with consistent amplitude and period; both traces stay stable and visible together for the entire video; and no visual glitch, blocked view, or misaligned cable obscures either channel or its connection path.

Scientific and Causal Correctness rubric:
level_1: The digital trace looks like an analog shape (a ramp, sawtooth, or noisy signal) instead of a clean two-level square wave, or the carrier trace looks non-sinusoidal (square, triangular, or a flat line); or the two traces look identical to each other; or the video depicts modulation effects (like a QAM constellation pattern or an amplitude envelope) as if they were part of what these two channels show.
level_2: One of the two traces matches its expected shape (for instance, the digital trace is a proper square wave) but the other is fundamentally wrong (for instance, the carrier shows noise instead of a sine wave); or both traces appear but lack their defining features: the square wave's edges are rounded with no clear transitions, or the sine wave's cycles are broken or discontinuous.
level_3: The digital signal appears as a clean binary square wave with only two voltage levels and no in-between steps; the carrier signal appears as a continuous sine wave; both are visible on the oscilloscope at the same time; and nothing in the scene suggests these two channels are showing a modulated output rather than the modulator's two raw inputs.
level_4: Everything at level 3 holds, and in addition the square wave's rising and falling edges look sharp with no visible slew or rounding; the sine wave shows at least two full, symmetric cycles with evenly spaced zero-crossings; and both traces keep a constant vertical scale and share the same horizontal timebase, with no auto-scaling jump on either channel.
level_5: Everything at level 4 holds, and in addition the square wave sits at exactly two clearly separated amplitude levels (e.g., roughly 0 V and +5 V), with no overlap or in-between level; the sine wave curves smoothly between each peak and trough with no flattening, clipping, or other distortion; and the two channels stay in step with each other in time, starting and ending together within the visible window, with no phase drift between them.

Spatiotemporal Consistency rubric:
level_1: A device appears or disappears abruptly between frames; the oscilloscope screen flickers, tears, or spins suddenly; a waveform trace jumps to a different position, height, or timing with no transition; a cable disconnects and reconnects with no motion causing it; or the overall lighting changes violently from one frame to the next.
level_2: At least one major break occurs: for example, the oscilloscope display freezes while everything else keeps moving; a waveform trace disappears for at least a frame and comes back at a different vertical position; a cable's connection point shifts with no motion in between; or the camera's perspective rotates or zooms with a visible jump instead of a smooth move.
level_3: The three devices stay in the same relative positions throughout; the oscilloscope screen shows steady, non-flickering waveforms the whole time; if the traces scroll, they do so smoothly (a static, non-scrolling display is also acceptable, since the prompt does not require scrolling); every cable stays attached at the same point; and nothing on screen suddenly jumps in position, size, or rotation.
level_4: Everything at level 3 holds, and in addition both waveform traces stay continuously visible with no blocked view, blinking, or interlacing artifacts; every cable follows a physically sensible path with no floating segments; device labels and icons stay legible and stay put relative to their own device; and foreground and background elements shift together consistently as the camera moves, with no mismatched layering.
level_5: Everything at level 4 holds, and in addition every frame flows smoothly into the next, with no motion blur that doesn't match the camera's movement and no faint duplicate or ghost of either waveform; the sine wave never appears to freeze into a jumpy, strobe-like flicker instead of a smooth curve; and a cable that passes behind the oscilloscope's bezel in one frame stays correctly behind it rather than popping back in front with no visible reason.