I(t) · COS
Q(t) · SIN
IQ CONSTELLATION
SPECTRUM · DC CENTRED · ±1.5 kHz
STFT WATERFALL · TIME →
EYE · 2 SYMBOLS · I(t)
ANALYSIS CONTROLS ARE FLOATING OVER THE SCENE — DOCK THEM FROM THE PANEL.
COMPLEX: THE TRUE CORKSCREW — I AND Q AS CAPTURED.
EACH HAS A CONSTELLATION SIGNATURE — SPINNING (FREQ OFFSET), ANGULAR FUZZ (PHASE NOISE), ELLIPSE (IQ IMBALANCE), OFF-CENTRE (DC). APPLIES TO THE WHOLE SIGNAL; WATCH THE EVM READOUT.
RF VIEW SPINS THE BASEBAND UP BY A DEMO CARRIER — THE BLUE I SHADOW ON THE FLOOR BECOMES THE TRANSMITTED WAVEFORM.
TONES ARE FLOATING OVER THE SCENE — DOCK THEM FROM THE PANEL.
NEGATIVE FREQUENCY = COUNTER-ROTATING CORKSCREW. NOISE = COMPLEX AWGN — WATCH THE FLOOR BOIL, THEN TRY AVG / MAX HOLD.
CLICK A PANEL'S LABEL IN THE SCENE TO HIDE IT; BRING IT BACK HERE.
DRAG TO ORBIT · WHEEL TO ZOOM · SHIFT-DRAG TO PAN · DOUBLE-CLICK TO RESET
A complex exponential ej2πft drawn through time. Time runs left→right; the vertical axis is Q (quadrature), the depth axis is I (in-phase), so the default view looks down the time axis at the same I → / Q ↑ orientation as the constellation inset. A single tone is a perfect corkscrew: its rotation rate is its frequency, and its direction of twist is the sign of that frequency.
The sweeping plane slices the corkscrew at one instant. That intersection point — one I value, one Q value — is exactly what one IQ sample records. Watch it trace the circle in the constellation inset.
The projection on the floor is I(t) = cos — what a real-only receiver would see. The back-wall shadow is Q(t) = sin, the 90°-shifted copy that lets you tell +f from −f. The spectrum panel shows the FFT with DC centred: negative frequencies live left of centre, and a counter-rotating corkscrew puts its spike there.
Real RF is s(t) = Re{ x(t)·ej2πfct }: this baseband corkscrew spun up by a much faster one at the carrier frequency fc (up to 6 GHz here, covering the 2.4 and 5.8 GHz ISM bands). Your receiver rotates along with the carrier, so recorded IQ is only the slow leftover twist. A real carrier makes millions of turns per window — RF VIEW shows a slowed-down demo carrier instead, labelled with the true slowdown factor. In that view the I shadow on the floor is exactly what the antenna transmits, and the spinning constellation shows why you must remove the carrier before the IQ points stand still.