Figure 3

(a) Changes in the oscillator signal due to the addition of the strong injected signal \(a_{inj}(t)\) (green curve), where the summed signal, s(t) (red color) is equal to \(s(t)=a(t) +a_{inj}(t)\) and a(t) (blue curve) is the amplifier output. The waveform is split into cycles \(p=0..5\), where \(p=0\) denotes the last cycle of the CW part of the waveform before the pulse starts. The figure indicates that, as a function of the cycle number p, the injection changes the maximum amplitude of the pulse s(t) and shifts the times when it is obtained by \(\Delta t_p\), as given in Eq. 5. Since the time shift is proportional to the time derivative of the injected signal, \(\Delta t_{p=2}>0\) in cycle #2 and \(\Delta t_{p=5}<0\) in cycle #5, as denoted by the orange arrows. The calculation shown in the figure corresponds to the experimental results described in Sec. 4. (b) Calculated (red curve) and measured (blue curve) instantaneous frequency with respect to the frequency of the signal (green curve) before adding the injected signal. The measured results were extracted from the pulse waveform by using the Hilbert transform, and the calculated result was obtained using Eq. 6.