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A class of constant envelope OFDM phase modulated (OFDM-PM) signals is studied. The motivation behind UFRM-PM is to alleviate the high peak-to-averags power ratio of conventional OFDM systems, Power density spectrum plots and fractional out-of-band power curves are given. Far small modulation indices, the OFDM-PM signals are shown to be more spectrally contained than conventional OFDM. The signal space is studied by considering the correlation properties of the OFDM-PM signals. A perj5onnance bound on the optimum OFDM-PM receiver is compared to simulation results. Also, a sub-optimum phase demodulator receiver is analyzed and an AWGN per$ormanca approximation is compared to simulation results. It is shown that for a small modulation index and high signal-lo-noise ratio, the sub-optimum receiver performs close to the optimum receiver

In normal woodwind tone production the nonlinear flow control properties of the reed transfer energy among the harmonics of the spectrum, and the favored pla•dng frequency is one for which the air column input impedance is high at several harmonics. Above the middle of the second register, woodwinds have only one participating impedance peak; yet these notes can be played even without the use of a register hole, despite competing possibilities of low register intermode cooperation. Such notes are possible bccaus• enhancement of the reed's transconductance ,4 near its own resonance frequency can offset the small input impedance Z of the air column so that (ZA --1)>0, providing an additional means for energy production above cutoff. Spectral levels as a function of blowing pressure, air column impedance, and reed characteristics are derived. Experiments on the clarinet show that the player can adjust the reed resonance frequency from about 2 to 3 kHz. When the reed frequency is adjusted to match a harmonic component of the tone, the amplitude of that component is increased, and the oscillation is heard as being stabilized in loudness, pitch, and tone color. PACS numbers: 43.75.Ef, 43.25. --x 1299 J. Acoust. So• An/. 66(5). Nov. lg79