Waveforms were used to compute individual spectra that were Trace is a spectrum average, indicated by the (also greyed out)Īvg Spect at the left end of the main toolbar: Multiple

The button is also shown disabled hereīecause there is no corresponding waveform to be shown if it The Spectrum button in the toolbar is shown depressed for Lowered the noise floor by 27 dB, allowing good resolution of Waveform averaging yields a 3 dB noise reductionįor every doubling of the number of frames 512 frames has thus The Hann windowįunction was applied to the wave average when displaying its Which took a little over 8 seconds to acquire. Synchronous waveform average of 512 frames to reduce noise, The lowest trace labeled 'Wave 512' was obtained using a Obscured not only the noise floor, but the harmonic distortion Note that the spectral leakage 'skirts' have It did use the same exponential spectral averaging as the The upper trace labeled 'Raw' used no window function, although What each of the traces looked like that were averaged together Instantaneous spectrum with no averaging. 'Inst', which used the same Hann window function, but is an The '32TC' trace overlays the dimmer, noisy trace labeled Tilt of the noise floor above 20 kHz results from the card's Noise is about 100 dB down at most frequencies. Third harmonic is more than 80 dB down (0.01%), and the background The cursor readouts for the selected trace show second-harmonicĭistortion 66.8 dB below the fundamental (0.046%). Slightly slowed reponse when the signal changes. This time constant providesĬomfortable viewing of noisy real-time signals, with only a Using spectral averaging in Exponential mode with a Harmonic distortion peak at 8000 Hz, though the third harmonicĪt 12000 is poorly resolved. Spectral leakage, allowing easy resolution of the second

The selected trace used a Hann window function to reduce The Juxt Trace Label Field has been set to show theĬontents of the Field labeled 'Average', which is '32TC' for The other traces have been dimmed with the highlightĬontrol. Shown with full brightness, to indicate that theĬursor readouts and labeled Fields refer to this trace They were saved to Juxt Array memory andĭisplayed with no added offset or spacing, to allowĭirect comparison.

The four traces used different windowing and averaging Performance of the card, since it includes both input and The above image shows four versions of the spectrum obtainedĭrive a sound card input with a 4000 Hz sine wave via a simple Data AcQuisition And Real-Time Analysis Scope - Spectrum - Spectrogram - Signal Generator

Dw spectrum axis t8311