What Cascade does · Power & THD

Power & THD (live)

What it shows. A live meter: voltage, power into a chosen load, and THD+N, updating continuously on both channels while you drag the generator level.

The theory. It is the same level and THD+N measurement as the sweeps, run continuously. Power is the measured voltage squared over the selected load resistance, and DUT GAIN is the returned level relative to the generator level, in dB.

Operating it. Set FREQUENCY, INPUT, LOAD and CH B, press START METER, then drag GENERATOR LEVEL and watch the readouts follow.

Status. Hardware-verified in Tests 1 to 4: −20.04 dBV read at −20 set, and the meter followed a preamp's volume knob over about 70 dB. Test 6, into a real amplifier, has not been run.

The live Power & THD meter, 2026-08-29: generator at −20 dBV (0.1000 Vrms), Channel A returning 0.0425 Vrms, THD+N 0.0184 %, power into 8 Ω. The "DUT GAIN −7.4 dB" in this shot is wrong: it was the "7.4 dB cable loss" that turned out to be a decode bug (a frozen range exponent), fixed the same week. It is the only Power & THD screenshot so far.
The live Power & THD meter, 2026-08-29: generator at −20 dBV (0.1000 Vrms), Channel A returning 0.0425 Vrms, THD+N 0.0184 %, power into 8 Ω. The "DUT GAIN −7.4 dB" in this shot is wrong: it was the "7.4 dB cable loss" that turned out to be a decode bug (a frozen range exponent), fixed the same week. It is the only Power & THD screenshot so far. App as of 2026-08-29.