Digital voltage controlled oscillator

Abstract

Abstract PURPOSE:To improve the linearily to a control signal by connecting a capacity element which functions to vary the oscillation frequency of a crystal oscillator circuit to an oscillator circuit on time division basis by a switching element in accordance with a digital control signal. CONSTITUTION:An N-bit digital signal is supplied to a binary rate multiplier 48 via a control signal line 49, and the pulses are produced in the number corresponding to the control signals. A CMOS switch 43 closes just for a period nT1 in a cycle T0 to connect a capacitor 44 between the earth and the input of an MOS inverter 40. This equals to a case where the capacity C0XnT1/T0 is always connected between the earth and the input of the inverter 40. In this case, the capacity of the capacitor 44 is defined as C0. As a result, control is possible for an oscillation frequency having extremely satisfactory linearity.

Inventors

• 👤 Masaaki Kato
• 👤 正昭 加藤

Bibliographic Details