but not restricting example t d u2032 is assumed to be equal to t d and r 1 u2032 is assumed to be equal to u2212 r 1 in fig5 if the ratio of slope r 1 to slope r 2 is fixed the dotted line of the oscillating signal at the area with a slope u2212 r 1 will be intersected with the oscillating signal at the area with a slop r 1 at point a of the high trigger level v h coincidentally the waveform composed of the oscillating signals at the areas with slopes r 1 u2212 r 1 and the extended dotted line of the oscillating signal in the area with a slope u2212 r 1 is an ideal path for the waveform of the prior art oscillating signal without taking the delay time t d into consideration the frequency of the oscillating signal produced by the oscillating signal generator 400 according to the present invention is equivalent to that of the oscillating signal produced under the condition of having no delay time t d therefore the oscillating signal produced according to the present invention still has the waveform produced at the high trigger level v h with a delay time td so as to eliminate phase noises and jitters the frequency of the oscillating signal produced according to the present invention is not related to the delay time td so as to achieve the best modulation linearity further the result of the frequency of the oscillating signal.