| Popis: |
The studies are devoted to the consideration of issues related to the capabilities and charac-teristics of frequency multipliers of harmonic oscillations, built on the basis of an oscillating circuit and a voltage limiter. From the harmonic signal, the voltage limiter allows generating the voltage pulses, which are parts of the sinusoid and having the required cutoff angle. These voltage pulses are used to control the oscillation circuit in order to provide multiplication of the frequency of the input signal when tuning the parameters of the oscillator circuit of the frequency multiplier by the corresponding frequencies multiples of the frequency of the input signal. It is shown that the use of a bipolar transistor included in a common-base circuit and acting as a voltage limiter makes it possible to construct a harmonic oscillation frequency oscillator with characteristics better than those in which the bipolar transistor is connected in a common-emitter circuit. In this device, the influence of the Miller effect on the frequency properties of the frequency multiplier is eliminated, which contributes to a significant increase in the upper frequency of the device. So the upper frequency of the frequency multiplier on the basis of the voltage limiter can be increased by at least 20 times, in comparison with the frequency multiplier, in which the bipolar transistor is switched on in a common-emitter circuit. It should be noted that, in the frequency multiplier under consideration, it is possible to use both parallel and series oscillatory circuits. Technically, the choice of the type of the oscillatory circuit is determined by the resistor values of the resistors passing the input signal to the oscillatory circuit. The use of a serial oscillatory circuit in the frequency multiplier allows reducing the supply voltage of the device as a whole. It is shown that a frequency multiplier constructed on the basis of a voltage limiter allows multiplying the frequency multiplication up to 5–7, since the device can use input signals having a high intensity, without disturbing the bipolar transistor. |
