Frequency Determination Method of the Sweep-Generator of the Panoramic Frequency Characteristics Meter

Abstract

Usage of the panoramic meters of frequency-response characteristics or frequency-response characteristic tracers significantly increases work productivity of adjusters and operators of radioelectronic and telecommunication systems. One of the main functions of the frequency-response characteristic tracer is formation of frequency-response scale, that is determining sweep generator frequency, which is a part of it. High-quality frequency-response characteristic tracers must have little error of scale bars formation in the broad frequency range, automatically and independently define their frequency of the swing band of the sweep generator. There is a basic structural scheme of the sweep generator frequency meter with a single-channel frequency-time converter, the main units of which include two reference-frequency generators and stroboscopic mixer. It is proved that usage of reference-frequency generators on quartz-crystal resonators reduces to zero the error component of frequency defining, provided by frequency instability of the generator. To compensate the deflection non-linearity influence of the sweep generator on frequency determination accuracy, the basic scheme of the meter was added with the third reference-frequency generators, as well as the operating procedure of the control and evaluation unit was changed. The evaluating formulas were received for the sweep generator frequency, on their basis the mathematical models for deflection non-linearity cases were created. As a result of the analysis it was found that in the new meter in comparison with the basic one the error component of frequency determination of the sweep generator caused by deflection non-linearity is decreased by times. Interrelation between the multiplication factor and deflection non-linearity coefficient was found, it can be used by designing of the sweep generator frequency meter and formation of the requirements to frequencies of reference-frequency generators. The developed meter with a single-channel frequency-time converter can be used in high-frequency characteristic tracers of 20 GHz and higher range. Its advantages include: simplicity, absence of fast-speed units, except for the stroboscopic mixer, transfer of measurements to great time range, that is to low frequencies.