| 摘要 |
An oscillator, constructed partially within an IC, includes a differential-input, differential-output, amplifier (Q1, Q2) within the IC. First and second resistive potential dividers (R11 - R16) located within the IC respectively divide the potentials appearing at the first and second output terminals of the amplifier in a predetermined ratio for respective application to the first and second input terminals, thereby respectively completing first and second direct-coupled regenerative feedback connections. An inductor (L1) located outside the IC is connected between the first and second input terminals of the amplifier and is anti-resonated by one or more capacitors (C1 - C3), which may be located inside or outside the IC. In controlled versions of the oscillator, a further differential-input, differential-output amplifier (Q11, Q12) is included within the IC and connected to provide Miller amplification of capacitors used in anti-resonating the inductor. The gain of this further amplifier is electrically controlled for controlling the frequency of the oscillations generated by the oscillator. In addition to providing Miller feedback, which is degenerative in nature and tends in varying degree to reduce the amplitude of oscillations, this further amplifier is arranged for providing regenerative feedback to counteract this tendency to reduce the amplitude of oscillations. <IMAGE> |
