Frequency Converters of Sweep Generator Based on YIG Resonator
Keywords
Abstract
Improving the accuracy of measuring the frequency characteristics of electronic devices and communication lines is an important task. In order to solve it for panoramic microwave devices, sweep-generators based on a YIG resonator with improved metrological characteristics are being developed.
The article describes a new approach to creating a sweep generator. The self-oscillator at the YIG resonator is not covered by reverse control connections, and the circuit is supplemented with a frequency converter with reference oscillators. As a result, the error of setting the frequency of the sweep generator, which is caused by the instability of the parameters of the YIG resonator, is compensated. In addition, the output voltage of the oscillator has a minimum level of phase noise.
A frequency converter with a range reference oscillator, a frequency converter based on a quad and a frequency converter of a sweep generator in the swing stop mode are proposed. The principle of their work is explained, temporary waveforms and calculated expressions are given.
In a sweep generator with a frequency converter containing a range reference generator, it is additionally possible, in addition to the coordinate marks on the monitor screen, to form a measuring mark with any frequency. The high linearity of the dependence of the generation frequency of the YIG resonator on the control current makes it possible, using a piecewise linear approximation, to obtain information about the frequency at the cursor location on the monitor screen.
Quad-based frequency converters are installed in sweep-generators operating in linear and non-linear frequency change modes. The scheme of the frequency converter of the sweep-generator in the swing-out mode is also constructed on the basis of a quad.
The microcontroller of the sweep-generator with installed frequency converters adjusts the digital control code of the oscillator. As a result, the accuracy of determining the frequency increases i.e. decreases the measurement error of various frequency characteristics of devices and communication lines.
