| 摘要 |
PROBLEM TO BE SOLVED: To allow a voltage controlled oscillator to cope with fluctuation in a control voltage with a specific linearity by using an integration capacitor so as to directly couple a signal to emitters of upper transistor(TR) pair in the voltage controlled oscillator used widely in an integrated circuit form. SOLUTION: The voltage controlled oscillator is made up of a capacitor C tank and an inductor L tank, an external tank circuit and an oscillator connection AMP. Then an integration capacitor C is used to couple directly a signal to emitters of an upper TR pair (Q3, Q4, Q5, Q6) and a tank signal is shifted by 90 deg. with respect to the control signal. Then the control signal driven by the upper TR pair receives pre-distortion to keep a linearity relation between the control voltage V and an oscillated frequency F. Two diodes are connected in parallel in a pre-distortion network and a current density is selected carefully, then the voltage controlled oscillator copes with fluctuation in the control voltage with a linearity of e.g. 1%. |
