Control of Frequency in VCOs
A voltage-controlled capacitor is one method of making an LC oscillator vary its frequency in response to a control voltage. Any reverse-biased semiconductor diode displays a measure of voltage-dependent capacitance and can be used to change the frequency of an oscillator by varying a control voltage applied to the diode. Special-purpose variable capacitance varactor diodes are available with well-characterized wide-ranging values of capacitance. Such devices are very convenient in the manufacture of voltage-controlled oscillators For low-frequency VCOs, other methods of varying the frequency (such as altering the charging rate of a capacitor by means of a voltage controlled current source) are used. See Function generator.
The frequency of a ring oscillator is controlled by varying either the supply voltage, the current available to each inverter stage, or the capacitive loading on each stage.
Read more about this topic: Voltage-controlled Oscillator
Famous quotes containing the words control of, control and/or frequency:
“Time in the hand is not control of time,
Nor shattered fragments of an instrument
A proof against the wind; the wind will rise,
We can only close the shutters.”
—Adrienne Rich (b. 1929)
“A “super person” is one who expects to manage a career, home, and family with complete ease, expecting to maintain a perfect job, a perfect marriage, a perfect house, and perfect control of the children.”
—Joyce Portner (late 20th century)
“One is apt to be discouraged by the frequency with which Mr. Hardy has persuaded himself that a macabre subject is a poem in itself; that, if there be enough of death and the tomb in one’s theme, it needs no translation into art, the bold statement of it being sufficient.”
—Rebecca West (1892–1983)