Tunable oscillator with high stability and accurate frequency

摘要

A tunable oscillator with high frequency stability and accuracy which utilizes a counter that periodically checks the actual value of the frequency and depending upon the count reached in the counter stage produces one of two logic output signals such that the first signal is formed on the occurrence of a number from a first correlated number sequence which indicates a frequency deviation from the desired value in a first direction and the second number is formed on the occurrence of a number which deviates from the desired frequency in a second direction and wherein logic signals are used to directly or indirectly recharge a capacitor at varying time constants depending upon the frequence drift.