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Arcam FMJ CD23 CD player Measurements page 2
Linearity error (fig.4) was very low down to below -100dBFS, with noise then dominating the measurement. This noise can also be seen overlaying the three discrete voltage steps in the waveform of an undithered 1kHz tone at -90.31dBFS (fig.5).
Fig.4 Arcam FMJ CD23, left channel departure from linearity, 16-bit data (2dB/vertical div.).
Fig.5 Arcam FMJ CD23, waveform of undithered 1kHz sinewave at -90.31dBFS, 16-bit data.
The CD23's analog output stage seems to be bombproof. Loading it down with 600 ohms and feeding it with data representing a full-scale 50Hz tone resulted in a negligible amount of third-harmonic distortion and no high-order spuriae (fig.6). Similarly, driving the punishing combination of 19 and 20kHz tones, each at -6dBFS—which results in a waveform peaking at full scale into the same 600 ohm load—revealed negligible intermodulation products (fig.7).
Fig.6 Arcam FMJ CD23, spectrum of 50Hz sinewave, DC-1kHz, at 0dBFS into 600 ohms (linear frequency scale).
Fig.7 Arcam FMJ CD23, HF intermodulation spectrum, DC-22kHz, 19+20kHz at 0dBFS into 600 ohms (linear frequency scale).
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