Radio Physics and Radio Astronomy (Jun 2019)
LOCAL OSCILLATORS FOR MM-WAVELENGTH AERONOMIC RECEIVERS
Abstract
Purpose: A description of the original technical solutions of the solid-state highly stable local oscillators of the millimeter range and the results of the study of the main characteristics of the developed devices are given. The goal of the work is the development of small-sized stabilized generators with low power consumption for the use in the composition of superheterodyne receivers of the 2 mm and 3 mm ranges for aeronomic research. Design/methodology/approach: The created local oscillators are based on multiple multiplication of the reference signal with a phase locked loop. The output generator on the Gunn diode works without a varactor, with the frequency tuning by changing the voltage on the diode. To measure the spectral characteristics, a test signal of a separate highly stable heterodyne of an astronomical receiver was used. The spectrum of the investigated local oscillator was recorded by a parallel Fourier spectrum analyzer with the frequency resolution of 1 kHz per channel. Methods for the study of other basic characteristics were standard methods of radio measurements. Findings: Compact sources of the heterodyne signal of the mm-wavelength range with low power consumption (less than 20 W) were designed and tested. The output power of the local oscillators is at least 50 mW. The measured relative frequency instability is better than 10-8 when working with a thermostatted quartz reference source. The time resource of continuous work exceeds 2 years. Conclusions: Relative instability of frequency (10-8 ) and launch power (more than 50 mW) of the presented generators correspond to the characteristics of industrial mm-wavelength precision generators, the here developed generators (devices) being more economical, compact and cheaper. A number of proposed circuit and design solutions can be used by designers of similar equipment in the mm-wavelength range.
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