Figure 7b

Figure 7b: Fast Fourier transform display of the program #1-restored version of the
16 kHz / 16-bit multiple sine wave signal depicted in Figure 7a, after it had been
clipped to +12 decibels and re-sampled to 44.1 kHz.

Fast Fourier transform display of the program #1-restored version of the 16 kHz / 16-bit multiple sine wave signal depicted in Figure 7a, after it had been clipped to +12 decibels and re-sampled to 44.1 kHz. Frequency is on the horizontal axis from 0 to 10.00 kHz, and amplitude is on the vertical axis, in the same scale as Figure 7a. In frequency, the program #1-restored version includes high-amplitude spikes at the four locations of the sine wave signals, plus numerous spikes between them and beyond the 3400 Hz signal. These additional spikes are approximately 20 to 30 decibels lower in amplitude than those for the four sine wave signals, and some are harmonically related. The restoration process did not completely remove the harmonics and other interrelated signals introduced by the clipping process.