| 摘要 |
<p>A voltage controlled oscillator (VCO) comprises the series arrangement of two signal inverters (I1, I2) whose outputs (B, A) are coupled to the input of the first signal inverter (I1) through a feedback loop (FBL) having a resistor (R1) and a capacitor (C1) connected to the outputs (B, A) of the inverters (I1, I2). The VCO further includes a simple control circuit (SC) with a second resistor (R2) which is connected to the junction (C) of the first resistor (R1) and the capacitor (C1), and to a series arrangement of two diodes (D1, D2) arranged in the same direction, whose interconnected electrodes are connected to the second resistor (R2) and coupled to the input of the first inverter (I1). The other electrodes of the diodes (D1, D2) form inputs for two control voltages (+U, -U) varying symmetrically with respect to the mean value of the capacitor voltage, with which the frequency of the VCO can be varied over a continuous range. The VCO can be used over a wide range of frequency values and does not require any particular measures for obtaining a practically symmetrical signal shape of the voltage at the output (A) of the second inverter (I2).</p> |
